:root {
    --btn-padding-y: 15px;
    --btn-padding-x: 27px;
    --btn-min-height: 31px;
    --btn-font-size: 16px;
    --btn-border-radius: 20px;
    --btn-min-width: 165px;
    --btn-icon-size: 1.3em;
    
    /* 聊天组件拉伸限制 - 电脑版默认值 */
    --chat-initial-height: 300px;
    --chat-max-height-ratio: 0.7;
    --chat-min-height: 200px;
    --is-mobile: false;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-touch-callout: none;
    -webkit-user-select: none;
    user-select: none;
}

/* 允许选中的例外区域 */
.result,
.explanation,
.message-text,
.translation-result,
.translation-error,
.chat-input,
.advanced-input,
.advanced-textarea,
input[type="text"],
textarea,
.grammar-blank,
.grammar-text,
.grammar-sentence,
.grammar-paragraph,
.grammar-content,
.reading-paragraph,
.reading-content,
.reading-summary-title,
.reading-question-item,
.reading-question-label,
.reading-question-text,
.reading-text,
.rc-paragraph,
.rc-question-item,
.rc-question-text,
.rc-content {
    -webkit-touch-callout: text;
    -webkit-user-select: text;
    user-select: text;
}

/* ========== 自定义滚动条样式 ========== */

/* WebKit浏览器 (Chrome, Safari, 新版Edge) */
::-webkit-scrollbar {
    width: 16px;
    height: 16px;
}

::-webkit-scrollbar-track {
    background: #e3edf7;
    border-radius: 12px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, #c8dbed, #d0e2f0);
    border-radius: 12px;
    transition: background 0.3s ease;
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(180deg, #e8f2fa, #eaf4fc);
}

::-webkit-scrollbar-thumb:active {
    background: linear-gradient(180deg, #b8cee5, #c5dcea);
}

::-webkit-scrollbar-corner {
    background: #e3edf7;
    border-radius: 12px;
}

/* Firefox 浏览器 */
* {
    scrollbar-width: auto;
    scrollbar-color: #d0e2f0 #e3edf7;
}

body {
    font-family: 'Nunito', 'PingFang SC', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, #e3edf7 0%, #d4e6f9 50%, #e8f0f8 100%);
    color: #4a6fa5;
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    /* 始终为滚动条预留空间，防止滚动条消失时内容布局发生变化 */
    scrollbar-gutter: stable;
}

.background-decoration {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.bubble {
    position: absolute;
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, rgba(255, 255, 255, 0.8), rgba(173, 216, 230, 0.3));
    animation: float 20s ease-in-out infinite;
}

.bubble-1 {
    width: 120px;
    height: 120px;
    top: 10%;
    left: 10%;
    animation-delay: 0s;
}

.bubble-2 {
    width: 80px;
    height: 80px;
    top: 20%;
    right: 15%;
    animation-delay: -5s;
}

.bubble-3 {
    width: 100px;
    height: 100px;
    bottom: 30%;
    left: 20%;
    animation-delay: -10s;
}

.bubble-4 {
    width: 60px;
    height: 60px;
    bottom: 20%;
    right: 25%;
    animation-delay: -15s;
}

.bubble-5 {
    width: 150px;
    height: 150px;
    top: 40%;
    right: 5%;
    animation-delay: -7s;
    opacity: 0.4;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0) translateX(0) scale(1);
        opacity: 0.6;
    }
    25% {
        transform: translateY(-30px) translateX(20px) scale(1.05);
        opacity: 0.8;
    }
    50% {
        transform: translateY(-10px) translateX(-15px) scale(0.95);
        opacity: 0.7;
    }
    75% {
        transform: translateY(-40px) translateX(10px) scale(1.02);
        opacity: 0.5;
    }
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 30px 20px;
    position: relative;
    z-index: 1;
}

.header {
    text-align: center;
    margin-bottom: 40px;
    animation: fadeInDown 0.8s ease-out;
}

.title {
    font-size: 2.8em;
    color: #5d8ab8;
    margin-bottom: 8px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.1);
    letter-spacing: 2px;
}

.title-icon {
    font-size: 1.2em;
    margin-right: 10px;
    animation: bounce 2s ease-in-out infinite;
}

.subtitle {
    font-size: 1.1em;
    color: #7aa8d6;
    font-weight: 600;
}

@keyframes bounce {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-5px); }
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.menu {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-bottom: 35px;
    flex-wrap: wrap;
}

.menu-item {
    padding: 15px 25px;
    background: linear-gradient(135deg, #e3edf7, #d4e6f9);
    color: #5d8ab8;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
    position: relative;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    min-width: 120px;
    min-height: 110px;
}

.menu-icon {
    font-size: 1.5em;
}

.menu-item:hover:not(.disabled) {
    transform: translateY(-3px);
    box-shadow: 8px 8px 16px #b8bec8, -8px -8px 16px #ffffff;
    color: #7aa8d6;
}

.menu-item.active {
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
    color: #ffffff;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
    transform: translateY(-2px);
}

.menu-item.disabled {
    background: linear-gradient(135deg, #e8f0f8, #e3edf7);
    color: #a0b4c9;
    cursor: not-allowed;
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
}

.pending {
    font-size: 10px;
    margin-top: 5px;
    color: #a0b4c9;
    font-weight: normal;
}

.exercise-card {
    background: linear-gradient(135deg, #e3edf7, #d4e6f9);
    border-radius: 30px;
    padding: 40px;
    box-shadow: 12px 12px 24px #b8bec8, -12px -12px 24px #ffffff;
}

/* 卡片显示控制 */
.exercise-card.hidden {
    display: none !important;
}

/* ========== 页面入场动画 ========== */
/* 页面准备状态 - 元素在动画前不可见 */
.page-preparing .menu,
.page-preparing .exercise-card:not(.hidden),
.page-preparing .ai-chat-card {
    opacity: 0;
}

/* 页面入场状态 - 刷新页面或从其他页面返回时触发 */
.page-entering .menu {
    animation: fadeInUp 0.8s ease-out 0.2s both;
}

.page-entering .exercise-card:not(.hidden) {
    animation: scaleIn 0.6s ease-out 0.4s both;
}

.page-entering .ai-chat-card {
    animation: scaleIn 0.6s ease-out 0.6s both;
}

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.9);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.card-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 2px solid rgba(173, 216, 230, 0.5);
}

.card-header h2 {
    color: #5d8ab8;
    font-size: 1.8em;
    font-weight: 700;
}

.progress-indicator {
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    padding: 8px 16px;
    border-radius: 15px;
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
    font-weight: 700;
    color: #5d8ab8;
    font-size: 1.1em;
}

.progress-indicator .divider {
    margin: 0 5px;
    color: #a0b4c9;
}

.instructions {
    color: #6a9bc8;
    margin-bottom: 25px;
    font-size: 1.15em;
    font-weight: 600;
    text-align: center;
    padding: 15px;
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    border-radius: 15px;
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
}

.instructions-icon {
    font-size: 1.3em;
    margin-right: 8px;
    animation: pulse 2s ease-in-out infinite;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.1); }
}

.words-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 15px;
    min-height: 100px;
    margin: 30px 0;
    padding: 30px;
    border-radius: 25px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    box-shadow: inset 6px 6px 12px #ccd9e6, inset -6px -6px 12px #ffffff;
    transition: all 0.3s ease;
}

.words-container:hover {
    box-shadow: inset 8px 8px 16px #ccd9e6, inset -8px -8px 16px #ffffff;
}

.word-item {
    padding: 14px 20px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    color: #5d8ab8;
    border-radius: 20px;
    cursor: move;
    user-select: none;
    font-weight: 600;
    font-size: 1.1em;
    min-width: 70px;
    text-align: center;
    box-shadow: 5px 5px 10px #b8bec8, -5px -5px 10px #ffffff;
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease, opacity 0.2s ease;
    border: 2px solid transparent;
    -webkit-tap-highlight-color: transparent;
    touch-action: none;
    will-change: transform, opacity;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    transform: translateZ(0);
}

.word-item:hover,
.word-card:not(.flipped):hover {
    transform: translateY(-3px);
    box-shadow: 8px 8px 16px #b8bec8, -8px -8px 16px #ffffff;
    background: linear-gradient(135deg, #f0f6fc, #e3edf7);
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

.word-card:not(.flipped):hover .word-card-front {
    background: linear-gradient(135deg, #f0f6fc, #e3edf7);
    transition: background 0.2s ease;
}

.word-item.dragging,
.word-card.dragging {
    opacity: 0.4;
    transform: scale(1);
    box-shadow: 5px 5px 10px #b8bec8, -5px -5px 10px #ffffff;
    z-index: 100;
    transition: opacity 0.1s ease;
}

.word-item.drag-over,
.word-card.drag-over {
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
    color: #ffffff;
    box-shadow: inset 4px 4px 8px #4a6fa5, inset -4px -4px 8px #7aa8d6;
    transform: scale(1.05) translateZ(0);
    transition: all 0.15s ease;
    border-radius: 20px;
}

.word-card.drag-over .word-card-front,
.word-card.drag-over .word-card-back {
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
    color: #ffffff;
    box-shadow: inset 4px 4px 8px #4a6fa5, inset -4px -4px 8px #7aa8d6;
    border-radius: 20px;
}

.word-item:active,
.word-card:active {
    transform: scale(0.95);
    background: linear-gradient(135deg, #d4e6f9, #c5d8f0);
}

.word-item.flipping,
.word-card.flipping {
    cursor: pointer;
}

.word-card.flipping:not(.flipped):hover .word-card-inner {
    transform: translateY(-3px);
    transition: transform 0.2s ease;
}

.word-card {
    perspective: 1000px;
    width: auto;
    height: auto;
    display: inline-block;
    border-radius: 20px;
    will-change: transform;
    transform: translateZ(0);
    transition: transform 0.2s ease, box-shadow 0.2s ease, background 0.2s ease;
}

/* 翻转后的卡片禁用hover效果，防止干扰翻转 */
.word-card.flipped:hover {
    background: none;
    box-shadow: none;
}

.word-card.flipped:hover .word-card-front,
.word-card.flipped:hover .word-card-back {
    background: linear-gradient(135deg, #d4e6f9, #c5d8f0);
    color: #5d8ab8;
}

.word-card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1);
    transform-style: preserve-3d;
    -webkit-transform-style: preserve-3d;
    will-change: transform;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
}

.word-card.flipped .word-card-inner {
    transform: rotateY(180deg);
    -webkit-transform: rotateY(180deg);
}

.word-card-front,
.word-card-back {
    position: relative;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden\9;
}

.word-card-front {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 14px 20px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    color: #5d8ab8;
    border-radius: 20px;
    font-weight: 600;
    font-size: 1.1em;
    box-shadow: 5px 5px 10px #b8bec8, -5px -5px 10px #ffffff;
    transform: translateZ(0);
    will-change: transform;
}

.word-card-back {
    position: absolute;
    top: 0;
    left: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 14px 20px;
    background: linear-gradient(135deg, #d4e6f9, #c5d8f0);
    color: #5d8ab8;
    border-radius: 20px;
    font-weight: 600;
    font-size: 1.1em;
    box-shadow: 5px 5px 10px #b8bec8, -5px -5px 10px #ffffff;
    transform: rotateY(180deg) translateZ(0);
    -webkit-transform: rotateY(180deg) translateZ(0);
    will-change: transform;
    transform: rotateY(180deg);
    -webkit-transform: rotateY(180deg);
}

/* 翻译加载状态样式 */
.translation-loading {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: #7aa8d6;
    font-size: 0.9em;
}

.translation-loading::before {
    content: '';
    width: 14px;
    height: 14px;
    border: 2px solid #7aa8d6;
    border-top-color: transparent;
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* 翻译结果样式 */
.translation-result {
    color: #5d8ab8;
    font-weight: 600;
    text-align: center;
    line-height: 1.4;
    word-break: break-word;
}

/* 翻译错误样式 */
.translation-error {
    color: #e74c3c;
    font-size: 0.9em;
    font-weight: 500;
}

/* 卡片翻译中状态 */
.word-card.translating .word-card-back {
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
}

/* 卡片已翻译状态 */
.word-card.translated .word-card-back {
    background: linear-gradient(135deg, #d4e6f9, #c5d8f0);
}

.word-card-touch-clone {
    position: fixed !important;
    z-index: 10000 !important;
    pointer-events: none !important;
    opacity: 1 !important;
    box-shadow: 5px 5px 10px #b8bec8, -5px -5px 10px #ffffff !important;
    transition: none !important;
    border-radius: 20px !important;
    -webkit-backface-visibility: visible;
    backface-visibility: visible;
    will-change: transform;
}

.word-card-touch-clone.flipped .word-card-inner {
    transform: rotateY(180deg);
    -webkit-transform: rotateY(180deg);
}

@media (hover: none) and (pointer: coarse) {
    .word-item {
        min-height: 44px;
        min-width: 44px;
        padding: 16px 22px;
        font-size: 1.2em;
    }

    .word-item:hover {
        transform: none;
    }

    .word-card-front,
    .word-card-back {
        min-height: 44px;
        min-width: 44px;
        padding: 16px 22px;
        font-size: 1.2em;
    }

    .word-card.flipping:hover .word-card-inner {
        transform: none;
    }
}

.actions {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin: 30px 0;
}

.btn {
    padding: var(--btn-padding-y) var(--btn-padding-x);
    border: none;
    border-radius: var(--btn-border-radius);
    cursor: pointer;
    font-size: var(--btn-font-size);
    font-weight: 700;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    align-items: center;
    gap: 8px;
    min-width: var(--btn-min-width);
    justify-content: center;
    height: auto;
    min-height: var(--btn-min-height);
}

.btn-icon {
    font-size: var(--btn-icon-size);
    margin: 0 5px;
}

.btn-check {
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
    color: #ffffff;
    box-shadow: 6px 6px 12px #4a6fa5, -6px -6px 12px #a5c8e8;
}

.btn-check:hover {
    transform: translateY(-3px);
    box-shadow: 8px 8px 16px #4a6fa5, -8px -8px 16px #a5c8e8;
    background: linear-gradient(135deg, #5d8ab8, #4a6fa5);
}

.btn-check:active {
    transform: translateY(0);
    box-shadow: inset 3px 3px 6px #4a6fa5, inset -3px -3px 6px #7aa8d6;
}

.btn-prev,
.btn-next {
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    color: #5d8ab8;
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
}

.btn-prev:hover,
.btn-next:hover {
    transform: translateY(-3px);
    box-shadow: 8px 8px 16px #b8bec8, -8px -8px 16px #ffffff;
    background: linear-gradient(135deg, #f0f6fc, #e8f0f8);
}

.btn-prev:active,
.btn-next:active {
    transform: translateY(0);
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
}

.result {
    margin-top: 25px;
    padding: 20px 30px;
    border-radius: 20px;
    font-weight: 700;
    font-size: 1.2em;
    text-align: center;
    min-height: 30px;
    transition: all 0.3s ease;
    box-shadow: inset 4px 4px 8px #ccd9e6, inset -4px -4px 8px #ffffff;
}

.result.correct {
    background: linear-gradient(135deg, #d4edda, #c3e6cb);
    color: #155724;
    box-shadow: inset 4px 4px 8px #a8d5a2, inset -4px -4px 8px #e8f5e9;
    animation: successPulse 0.5s ease-out;
}

.result.incorrect {
    background: linear-gradient(135deg, #f8d7da, #f5c6cb);
    color: #721c24;
    box-shadow: inset 4px 4px 8px #f1b0b7, inset -4px -4px 8px #fce8e8;
    animation: shake 0.5s ease-out;
}

@keyframes successPulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.02); }
    100% { transform: scale(1); }
}

@keyframes shake {
    0%, 100% { transform: translateX(0); }
    25% { transform: translateX(-5px); }
    75% { transform: translateX(5px); }
}

.explanation {
    margin-top: 15px;
    padding: 20px 25px;
    border-radius: 20px;
    font-weight: 600;
    font-size: 1.05em;
    line-height: 2;
    min-height: 30px;
    transition: all 0.3s ease;
    box-shadow: inset 4px 4px 8px #ccd9e6, inset -4px -4px 8px #ffffff;
    opacity: 0;
    transform: translateY(-10px);
    pointer-events: none;
}

.explanation.visible {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
    background: linear-gradient(135deg, #fff8e1, #fff3cd);
    color: #856404;
    box-shadow: 6px 6px 12px #d4c4a8, -6px -6px 12px #ffffff;
    animation: fadeInUp 0.4s ease-out;
}

.explanation.visible::before {
    content: '💡 参考答案：';
    display: inline-block;
    margin-right: 10px;
    margin-bottom: 8px;
    font-size: 1em;
    font-weight: 600;
}

@media (max-width: 768px) {
    :root {
        --btn-padding-y: 9px;
        --btn-padding-x: 14px;
        --btn-min-height: 38px;
        --btn-font-size: 15px;
        --btn-border-radius: 18px;
        --btn-min-width: 85px;
        --btn-icon-size: 1.1em;
        
        /* 手机版聊天组件拉伸限制 */
        --chat-initial-height: 250px;
        --chat-max-height-ratio: 0.75;
        --chat-min-height: 150px;
        --is-mobile: true;
    }

    .container {
        padding: 20px 15px;
    }

    .header {
        margin-bottom: 30px;
        margin-top: 20px;
    }

    .title {
        font-size: 2.4em;
        margin-bottom: 12px;
    }

    .title-icon {
        font-size: 1.3em;
        margin-right: 10px;
    }

    .subtitle {
        font-size: 1.2em;
    }

    .menu {
        gap: 10px;
        margin-bottom: 25px;
        flex-wrap: nowrap;
        overflow-x: auto;
        padding: 5px 30px;
        -webkit-overflow-scrolling: touch;
    }

    .menu-item {
        padding: 8px 6px;
        font-size: 10px;
        min-width: 65px;
        width: 65px;
        height: 65px;
        border-radius: 12px;
        flex-shrink: 0;
        box-shadow: 4px 4px 8px rgba(184, 190, 200, 0.5), -4px -4px 8px rgba(255, 255, 255, 0.8);
    }

    .menu-icon {
        font-size: 1.3em;
    }

    .pending {
        display: none;
    }

    .exercise-card {
        padding: 25px;
        border-radius: 25px;
    }

    .card-header {
        gap: 15px;
        text-align: left;
        margin-bottom: 20px;
        padding-bottom: 15px;
    }

    .card-header h2 {
        font-size: 1.3em;
    }

    .progress-indicator {
        padding: 6px 14px;
        font-size: 0.9em;
        border-radius: 12px;
    }

    .words-container {
        padding: 20px;
        gap: 12px;
        margin: 25px 0;
        min-height: 90px;
    }

    .word-item {
        padding: 12px 16px;
        font-size: 0.9em;
        min-width: 60px;
        min-height: 44px;
        border-radius: 18px;
    }

    .word-card-front,
    .word-card-back {
        padding: 12px 16px;
        font-size: 0.9em;
        min-width: 60px;
        min-height: 44px;
        border-radius: 18px;
    }

    .actions {
        gap: 12px;
        margin: 25px 0;
        justify-content: center;
        flex-wrap: wrap;
    }

    .result {
        font-size: 1em;
        padding: 18px 22px;
        margin-top: 18px;
    }

    .explanation {
        font-size: 0.95em;
        padding: 18px 22px;
        margin-top: 18px;
    }

    .bubble {
        display: none;
    }

    .ai-chat-card {
        padding: 25px;
        border-radius: 25px;
        margin-top: 25px;
    }

    .ai-chat-card .card-header {
        gap: 15px;
        text-align: left;
        margin-bottom: 8px;
        padding-bottom: 6px;
    }    .ai-chat-card .card-header h2 {
        font-size: 1.3em;
    }

    .ai-status-indicator {
        padding: 5px 12px;
        font-size: 0.9em;
        border-radius: 12px;
    }

    .chat-messages {
        padding: 15px;
        margin: 20px 0;
        min-height: var(--chat-min-height);
        height: auto;
        max-height: calc(var(--window-height) * var(--chat-max-height-ratio));
    }

    .message-avatar {
        width: 35px;
        height: 35px;
        min-width: 35px;
        font-size: 1.3em;
    }

    .message-content {
        max-width: calc(100% - 95px);
    }

    .message-text {
        padding: 12px 16px;
        font-size: 0.95em;
    }

    .chat-input {
        padding: 12px 16px;
        font-size: 0.95em;
    }

    .send-btn {
        width: 45px;
        height: 45px;
    }

    .input-hint {
        font-size: 0.8em;
    }
}

@media (max-width: 480px) {
    :root {
        --btn-padding-y: 8px;
        --btn-padding-x: 12px;
        --btn-min-height: 36px;
        --btn-font-size: 14px;
        --btn-border-radius: 15px;
        --btn-min-width: 80px;
        --btn-icon-size: 1em;
        
        /* 小屏幕手机版聊天组件拉伸限制 */
        --chat-initial-height: 220px;
        --chat-max-height-ratio: 0.8;
        --chat-min-height: 130px;
    }

    .container {
        padding: 15px 12px;
    }

    .header {
        margin-bottom: 25px;
        margin-top: 18px;
    }

    .title {
        font-size: 2.1em;
        letter-spacing: 1px;
    }

    .title-icon {
        font-size: 1.2em;
        margin-right: 8px;
    }

    .subtitle {
        font-size: 1.1em;
    }

    .menu {
        gap: 8px;
        margin-bottom: 20px;
        padding: 5px 25px;
    }

    .menu-item {
        padding: 6px 5px;
        font-size: 9px;
        min-width: 55px;
        width: 55px;
        height: 55px;
        border-radius: 10px;
        box-shadow: 3px 3px 6px rgba(184, 190, 200, 0.4), -3px -3px 6px rgba(255, 255, 255, 0.9);
    }

    .menu-icon {
        font-size: 1.1em;
    }

    .exercise-card {
        padding: 20px;
        border-radius: 20px;
    }

    .card-header {
        gap: 12px;
        text-align: left;
        margin-bottom: 18px;
        padding-bottom: 12px;
    }

    .card-header h2 {
        font-size: 1.1em;
    }

    .progress-indicator {
        padding: 5px 12px;
        font-size: 0.85em;
        border-radius: 10px;
    }

    .words-container {
        padding: 18px;
        gap: 10px;
        margin: 20px 0;
        min-height: 80px;
    }

    .word-item {
        padding: 10px 14px;
        font-size: 0.9em;
        min-width: 55px;
        min-height: 44px;
        border-radius: 15px;
    }

    .word-card-front,
    .word-card-back {
        padding: 10px 14px;
        font-size: 0.9em;
        min-width: 55px;
        min-height: 44px;
        border-radius: 15px;
    }

    .actions {
        gap: 10px;
        margin: 20px 0;
        justify-content: center;
        flex-wrap: wrap;
    }

    .result {
        font-size: 0.95em;
        padding: 15px 20px;
        margin-top: 15px;
        border-radius: 15px;
    }

    .explanation {
        font-size: 0.9em;
        padding: 15px 20px;
        margin-top: 15px;
        border-radius: 15px;
        line-height: 1.7;
    }

    .ai-chat-card {
        padding: 20px;
        border-radius: 20px;
        margin-top: 20px;
    }

    .ai-chat-card .card-header {
        gap: 12px;
        text-align: left;
        margin-bottom: 18px;
        padding-bottom: 12px;
    }

    .ai-chat-card .card-header h2 {
        font-size: 1.1em;
    }

    .ai-status-indicator {
        padding: 4px 10px;
        font-size: 0.85em;
        border-radius: 10px;
    }

    .chat-messages {
        padding: 12px;
        margin: 18px 0;
        min-height: var(--chat-min-height);
        height: auto;
        max-height: calc(var(--window-height) * var(--chat-max-height-ratio));
    }

    .message-avatar {
        width: 32px;
        height: 32px;
        min-width: 32px;
        font-size: 1.2em;
    }

    .message-content {
        max-width: calc(100% - 90px);
    }

    .message-text {
        padding: 10px 14px;
        font-size: 0.9em;
    }

    .chat-input {
        padding: 10px 14px;
        font-size: 0.9em;
    }

    .send-btn {
        width: 42px;
        height: 42px;
    }

    .input-hint {
        font-size: 0.75em;
    }
}

@media (max-width: 360px) {
    .menu {
        gap: 6px;
        padding: 5px 20px;
    }

    .menu-item {
        min-width: 50px;
        width: 50px;
        height: 50px;
        padding: 5px 4px;
        font-size: 8px;
        border-radius: 10px;
        box-shadow: 2px 2px 4px rgba(184, 190, 200, 0.3), -2px -2px 4px rgba(255, 255, 255, 0.95);
    }

    .menu-icon {
        font-size: 1em;
    }

    .header {
        margin-bottom: 22px;
        margin-top: 15px;
    }

    .title {
        font-size: 1.9em;
    }

    .subtitle {
        font-size: 1em;
    }
}

@media (max-height: 600px) and (orientation: landscape) {
    :root {
        --btn-padding-y: 8px;
        --btn-padding-x: 12px;
        --btn-min-height: 36px;
        --btn-font-size: 13px;
        --btn-border-radius: 15px;
        --btn-min-width: 75px;
        --btn-icon-size: 1em;
    }

    .header {
        margin-bottom: 20px;
        margin-top: 12px;
    }

    .title {
        font-size: 1.8em;
    }

    .subtitle {
        font-size: 0.95em;
    }

    .menu {
        gap: 8px;
        margin-bottom: 20px;
        padding: 5px 30px;
    }

    .menu-item {
        min-width: 55px;
        width: 55px;
        height: 55px;
        padding: 6px 5px;
        font-size: 9px;
        border-radius: 10px;
        box-shadow: 2px 2px 4px rgba(184, 190, 200, 0.3), -2px -2px 4px rgba(255, 255, 255, 0.95);
    }

    .menu-icon {
        font-size: 1.1em;
    }

    .exercise-card {
        padding: 18px;
    }

    .card-header {
        margin-bottom: 15px;
        padding-bottom: 10px;
    }

    .card-header h2 {
        font-size: 1.1em;
    }

    .progress-indicator {
        padding: 4px 10px;
        font-size: 0.8em;
        border-radius: 10px;
    }

    .words-container {
        padding: 15px;
        margin: 15px 0;
        min-height: 70px;
    }

    .word-item {
        padding: 8px 12px;
        font-size: 0.85em;
        min-height: 44px;
    }

    .word-card-front,
    .word-card-back {
        padding: 8px 12px;
        font-size: 0.85em;
        min-height: 44px;
    }

    .actions {
        margin: 15px 0;
        gap: 8px;
        justify-content: center;
        flex-wrap: wrap;
    }
}

.ai-chat-card {
    background: linear-gradient(135deg, #e3edf7, #d4e6f9);
    border-radius: 30px;
    padding: 15px 30px 20px 30px;
    box-shadow: 12px 12px 24px #b8bec8, -12px -12px 24px #ffffff;
    margin-top: 15px;
    /* 向上拉伸布局 */
    display: flex;
    flex-direction: column;
}

.ai-chat-card .card-header {
    gap: 15px;
    text-align: left;
    margin-bottom: 33px;
    margin-top: 0px;
    padding-bottom: 13px;
    padding-top: 15px;
    justify-content: space-between;
}

.ai-chat-card .card-header h2 {
    display: flex;
    align-items: center;
}

.ai-status-indicator {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 0;
    border-radius: 0;
    box-shadow: none;
    margin-left: 12px;
    vertical-align: middle;
}

.status-dot {
    width: 4px;
    height: 4px;
    background: linear-gradient(135deg, #4ade80, #22c55e);
    border-radius: 50%;
    animation: pulse 2s ease-in-out infinite;
}

.status-text {
    font-size: 0.1em;
    font-weight: 600;
    color: #22c55e;
}

.new-chat-btn {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 10px 12px;
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    color: #5d8ab8;
    border: none;
    border-radius: 15px;
    cursor: pointer;
    font-size: 1.1em;
    font-weight: 700;
    box-shadow: inset 2px 2px 4px #ccd9e6, inset -2px -2px 4px #ffffff;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.new-chat-btn:hover {
    transform: translateY(0);
    box-shadow: inset 4px 4px 8px #ccd9e6, inset -4px -4px 8px #ffffff;
}

.new-chat-btn:active {
    transform: translateY(0);
    box-shadow: inset 5px 5px 10px #ccd9e6, inset -5px -5px 10px #ffffff;
}

.new-chat-icon {
    font-size: 1.1em;
}

.chat-messages {
    margin: 0 0 12px 0;
    padding: 12px;
    border-radius: 20px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    box-shadow: inset 6px 6px 12px #ccd9e6, inset -6px -6px 12px #ffffff;
    min-height: var(--chat-min-height);
    max-height: calc(var(--window-height) * var(--chat-max-height-ratio));
    overflow-y: auto;
    overflow-x: hidden;
    position: relative;
    /* 正常布局，默认消息显示在上方 */
    display: flex;
    flex-direction: column;
    /* 性能优化 */
    will-change: scroll-position;
    transform: translateZ(0);
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    -webkit-overflow-scrolling: touch;
    /* 隐藏滚动条 */
    scrollbar-width: none;
}

.chat-messages::-webkit-scrollbar {
    display: none;
}

/* 消息包装器 - 用于 column-reverse 布局中保持消息正常顺序 */
.chat-messages-wrapper {
    display: flex;
    flex-direction: column;
    width: 100%;
    /* 让消息默认从上方开始显示 */
    justify-content: flex-start;
    /* 默认消息稍微下移 */
    padding-top: 38px;
}

.chat-message {
    display: flex;
    gap: 15px;
    margin-bottom: 20px;
    animation: fadeInUp 0.4s ease-out;
    align-items: flex-start;
}

.chat-message:last-child {
    margin-bottom: 15px;
}

/* 新消息动画 - 从底部淡入 */
@keyframes messageSlideUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.message-avatar {
    width: 40px;
    height: 40px;
    min-width: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5em;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
}

.ai-message {
    flex-direction: row;
}

.user-message {
    flex-direction: row-reverse;
}

.message-avatar {
    width: 40px;
    height: 40px;
    min-width: 40px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5em;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
    flex-shrink: 0;
}

.ai-message .message-avatar {
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
}

.user-message .message-avatar {
    background: linear-gradient(135deg, #f0f6fc, #e8f0f8);
}

.message-content {
    flex: 1;
    max-width: calc(100% - 110px);
    transition: all 0.3s ease;
}

.message-text {
    padding: 15px 20px;
    border-radius: 20px;
    line-height: 1.6;
    font-size: 1em;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
}

.ai-message .message-text {
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    color: #4a6fa5;
    border-radius: 20px 20px 20px 5px;
}

.user-message .message-text {
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
    color: #ffffff;
    border-radius: 20px 20px 5px 20px;
}

.chat-input-container {
    margin-top: 20px;
}

.input-wrapper {
    display: flex;
    gap: 12px;
    align-items: center;
}

.chat-input {
    flex: 1;
    padding: 15px 20px;
    border: none;
    border-radius: 20px;
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    color: #4a6fa5;
    font-size: 1em;
    font-weight: 600;
    box-shadow: inset 4px 4px 8px #ccd9e6, inset -4px -4px 8px #ffffff;
    transition: all 0.3s ease;
    outline: none;
}

.chat-input::placeholder {
    color: #a0b4c9;
}

.chat-input:focus {
    box-shadow: inset 6px 6px 12px #ccd9e6, inset -6px -6px 12px #ffffff;
}

.send-btn {
    width: 50px;
    height: 50px;
    border: none;
    border-radius: 50%;
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
    color: #ffffff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 6px 6px 12px #4a6fa5, -6px -6px 12px #a5c8e8;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.send-btn:hover {
    transform: scale(1.05);
    box-shadow: 8px 8px 16px #4a6fa5, -8px -8px 16px #a5c8e8;
}

.send-btn:active {
    transform: scale(0.95);
    box-shadow: inset 3px 3px 6px #4a6fa5, inset -3px -3px 6px #7aa8d6;
}

.send-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.send-icon {
    font-size: 1.3em;
    margin-left: 2px;
}

.input-hint {
    text-align: center;
    font-size: 0.85em;
    color: #a0b4c9;
    margin-top: 18px;
    font-weight: 600;
}

.chat-message.loading .message-text {
    display: flex;
    align-items: center;
    gap: 8px;
}

.chat-message.loading .message-text::after {
    content: '';
    width: 20px;
    height: 20px;
    border: 3px solid #e8f0f8;
    border-top-color: #7aa8d6;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* ========== AI消息实时格式化样式 ========== */

/* 流式消息样式 - 消息还在接收中 */
.message-text.streaming {
    position: relative;
}

/* 流式输入光标 */
.message-text.streaming::after {
    content: '';
    display: inline-block;
    width: 2px;
    height: 1em;
    background: #7aa8d6;
    margin-left: 2px;
    vertical-align: text-bottom;
    animation: cursorBlink 1s ease-in-out infinite;
}

@keyframes cursorBlink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.3; }
}

/* 流式文本容器 */
.streaming-text {
    white-space: pre-wrap;
    word-break: break-word;
}

/* AI消息段落样式 */
.ai-paragraph {
    margin: 0 0 0.8em 0;
    line-height: 1.7;
}

.ai-paragraph:last-child {
    margin-bottom: 0;
}

/* AI消息中的加粗文本 */
.message-text strong {
    font-weight: 700;
    color: #3d5a80;
    -webkit-user-select: text;
    user-select: text;
}

.ai-message .message-text strong {
    color: #3d5a80;
}

.user-message .message-text strong {
    color: #ffffff;
}

/* AI消息中的斜体文本 */
.message-text em {
    font-style: italic;
    color: #5d8ab8;
    -webkit-user-select: text;
    user-select: text;
}

.user-message .message-text em {
    color: rgba(255, 255, 255, 0.9);
}

/* AI消息中的行内代码 */
.message-text .inline-code {
    font-family: 'Consolas', 'Monaco', 'Courier New', monospace;
    font-size: 0.9em;
    padding: 2px 6px;
    border-radius: 4px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    color: #4a6fa5;
    box-shadow: inset 1px 1px 2px rgba(0, 0, 0, 0.05);
    -webkit-user-select: text;
    user-select: text;
}

.user-message .message-text .inline-code {
    background: rgba(255, 255, 255, 0.2);
    color: #ffffff;
    box-shadow: none;
}

/* 消息文本内容样式优化 */
.message-text p {
    margin: 0 0 0.6em 0;
}

.message-text p:last-child {
    margin-bottom: 0;
}

/* 消息内换行 */
.message-text br {
    line-height: 1.5;
}

/* 流式消息 loading 状态优化 */
.chat-message.loading .message-text.streaming::after {
    display: none;
}

@keyframes messageSlideIn {
    from {
        opacity: 0;
        transform: translateY(20px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

@keyframes messageSlideOut {
    from {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
    to {
        opacity: 0;
        transform: translateY(-20px) scale(0.95);
    }
}

@keyframes resizeLimitPulse {
    0% { opacity: 0.6; transform: scaleX(1); }
    50% { opacity: 1; transform: scaleX(1.2); }
    100% { opacity: 0.6; transform: scaleX(1); }
}

@keyframes limitFlash {
    0% { box-shadow: inset 6px 6px 12px #ccd9e6, inset -6px -6px 12px #ffffff, 0 0 0 3px rgba(220, 38, 38, 0.5); }
    100% { box-shadow: inset 6px 6px 12px #ccd9e6, inset -6px -6px 12px #ffffff; }
}

/* ========== 头像更换模态窗口样式 ========== */
.avatar-modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10000;
    animation: fadeIn 0.3s ease-out;
}

.avatar-modal.active {
    display: block;
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

.avatar-modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(74, 111, 165, 0.5);
    backdrop-filter: blur(5px);
}

.avatar-modal-content {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: linear-gradient(135deg, #e3edf7, #d4e6f9);
    border-radius: 30px;
    padding: 35px;
    box-shadow: 12px 12px 24px #b8bec8, -12px -12px 24px #ffffff;
    max-width: 450px;
    width: 90%;
    animation: modalSlideIn 0.3s ease-out;
}

@keyframes modalSlideIn {
    from {
        opacity: 0;
        transform: translate(-50%, -45%) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }
}

.avatar-modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 25px;
    padding-bottom: 15px;
    border-bottom: 2px solid rgba(173, 216, 230, 0.5);
}

.avatar-modal-header h3 {
    color: #5d8ab8;
    font-size: 1.5em;
    font-weight: 700;
    margin: 0;
}

.avatar-modal-close {
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    border: none;
    border-radius: 50%;
    width: 35px;
    height: 35px;
    font-size: 1.5em;
    color: #5d8ab8;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: inset 2px 2px 4px #ccd9e6, inset -2px -2px 4px #ffffff;
    transition: all 0.3s ease;
}

.avatar-modal-close:hover {
    background: linear-gradient(135deg, #f0f6fc, #e8f0f8);
    transform: rotate(90deg);
}

.avatar-modal-close:active {
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
}

.avatar-modal-body {
    margin-bottom: 25px;
}

.avatar-preview-container {
    display: flex;
    justify-content: center;
    margin-bottom: 25px;
}

.avatar-preview {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
    overflow: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
}

.avatar-preview-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    display: block;
}

.avatar-preview-default {
    font-size: 4em;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: #5d8ab8;
    z-index: 1;
}

.avatar-preview.has-image .avatar-preview-default {
    display: none;
}

.avatar-presets-section {
    text-align: center;
    margin-bottom: 25px;
}

.presets-title {
    font-size: 0.95em;
    color: #5d8ab8;
    font-weight: 600;
    margin-bottom: 15px;
}

.avatar-presets {
    display: flex;
    justify-content: center;
    gap: 15px;
    flex-wrap: wrap;
}

.avatar-preset {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    overflow: hidden;
    cursor: pointer;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    border: 3px solid transparent;
}

.avatar-preset:hover {
    transform: scale(1.1);
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
}

.avatar-preset.selected {
    border-color: #7aa8d6;
    box-shadow: 0 0 0 3px rgba(122, 168, 214, 0.3);
}

.avatar-preset img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

.avatar-upload-section {
    text-align: center;
}

.avatar-upload-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
    color: #ffffff;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    font-size: 1em;
    font-weight: 600;
    box-shadow: 6px 6px 12px #4a6fa5, -6px -6px 12px #a5c8e8;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.avatar-upload-btn:hover {
    transform: translateY(-2px);
    box-shadow: 8px 8px 16px #4a6fa5, -8px -8px 16px #a5c8e8;
    background: linear-gradient(135deg, #5d8ab8, #4a6fa5);
}

.avatar-upload-btn:active {
    transform: translateY(0);
    box-shadow: inset 3px 3px 6px #4a6fa5, inset -3px -3px 6px #7aa8d6;
}

.upload-icon {
    font-size: 1.2em;
}

.upload-hint {
    margin-top: 12px;
    font-size: 0.85em;
    color: #7aa8d6;
    font-weight: 600;
}

.avatar-modal-footer {
    display: flex;
    gap: 12px;
    justify-content: flex-end;
}

.avatar-btn {
    padding: 12px 24px;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    font-size: 1em;
    font-weight: 600;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    min-width: 100px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
}

.avatar-btn-cancel {
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    color: #5d8ab8;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
}

.avatar-btn-reset {
    background: linear-gradient(135deg, #f8d7da, #f5c6cb);
    color: #721c24;
    box-shadow: 4px 4px 8px #f1b0b7, -4px -4px 8px #fce8e8;
}

.avatar-btn-reset:hover {
    transform: translateY(-2px);
    box-shadow: 6px 6px 12px #f1b0b7, -6px -6px 12px #fce8e8;
    background: linear-gradient(135deg, #f9e1e4, #f8d7da);
}

.avatar-btn-reset:active {
    transform: translateY(0);
    box-shadow: inset 3px 3px 6px #f1b0b7, inset -3px -3px 6px #fce8e8;
}

.avatar-btn-reset:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

.avatar-btn-cancel:hover {
    transform: translateY(-2px);
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
    background: linear-gradient(135deg, #f0f6fc, #e8f0f8);
}

.avatar-btn-cancel:active {
    transform: translateY(0);
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
}

.avatar-btn-confirm {
    background: linear-gradient(135deg, #7aa8d6, #5d8ab8);
    color: #ffffff;
    box-shadow: 6px 6px 12px #4a6fa5, -6px -6px 12px #a5c8e8;
}

.avatar-btn-confirm:hover {
    transform: translateY(-2px);
    box-shadow: 8px 8px 16px #4a6fa5, -8px -8px 16px #a5c8e8;
    background: linear-gradient(135deg, #5d8ab8, #4a6fa5);
}

.avatar-btn-confirm:active {
    transform: translateY(0);
    box-shadow: inset 3px 3px 6px #4a6fa5, inset -3px -3px 6px #7aa8d6;
}

.avatar-btn-confirm:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    transform: none;
}

/* 头像可点击提示 */
.message-avatar.clickable {
    cursor: pointer;
    transition: all 0.3s ease;
}

.message-avatar.clickable:hover {
    transform: scale(1.1);
    box-shadow: 6px 6px 12px #4a6fa5, -6px -6px 12px #a5c8e8;
}

.message-avatar.clickable:active {
    transform: scale(0.95);
}

/* 头像图片样式 */
.message-avatar img {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    object-fit: cover;
    display: none;
}

.message-avatar.has-image {
    background: transparent;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
}

.message-avatar.has-image img {
    display: block;
}

.message-avatar.has-image::after {
    display: none;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .avatar-modal-content {
        padding: 25px;
        max-width: 90%;
    }

    .avatar-modal-header h3 {
        font-size: 1.3em;
    }

    .avatar-preview {
        width: 120px;
        height: 120px;
    }

    .avatar-preview-default {
        font-size: 3em;
    }

    .avatar-preset {
        width: 70px;
        height: 70px;
    }

    .presets-title {
        font-size: 0.9em;
    }

    .avatar-upload-btn {
        padding: 10px 20px;
        font-size: 0.9em;
    }

    .avatar-btn {
        padding: 10px 18px;
        font-size: 0.9em;
        min-width: 85px;
    }

    .upload-hint {
        font-size: 0.8em;
    }
}

@media (max-width: 480px) {
    .avatar-modal-content {
        padding: 20px;
        border-radius: 25px;
    }

    .avatar-modal-header {
        margin-bottom: 20px;
        padding-bottom: 12px;
    }

    .avatar-modal-header h3 {
        font-size: 1.2em;
    }

    .avatar-modal-close {
        width: 30px;
        height: 30px;
        font-size: 1.3em;
    }

    .avatar-preview {
        width: 100px;
        height: 100px;
    }

    .avatar-preview-default {
        font-size: 2.5em;
    }

    .avatar-preset {
        width: 60px;
        height: 60px;
    }

    .presets-title {
        font-size: 0.85em;
    }

    .avatar-modal-body {
        margin-bottom: 20px;
    }

    .avatar-upload-btn {
        padding: 9px 18px;
        font-size: 0.85em;
    }

    .upload-icon {
        font-size: 1.1em;
    }

    .upload-hint {
        font-size: 0.75em;
        margin-top: 10px;
    }

    .avatar-modal-footer {
        gap: 10px;
    }

    .avatar-btn {
        padding: 9px 16px;
        font-size: 0.85em;
        min-width: 75px;
    }
}

/* ========== 高级功能样式 ========== */
.avatar-advanced-section {
    margin-top: 20px;
    border-top: 2px solid rgba(173, 216, 230, 0.5);
    padding-top: 20px;
}

.avatar-advanced-toggle {
    width: 100%;
    padding: 12px 20px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    color: #5d8ab8;
    border: none;
    border-radius: 15px;
    cursor: pointer;
    font-size: 1em;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
    transition: all 0.3s ease;
}

.avatar-advanced-toggle:hover {
    background: linear-gradient(135deg, #f0f6fc, #e8f0f8);
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
}

.avatar-advanced-toggle:active {
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
}

.advanced-icon {
    font-size: 1.2em;
}

.toggle-arrow {
    margin-left: auto;
    transition: transform 0.3s ease;
}

.avatar-advanced-toggle.active .toggle-arrow {
    transform: rotate(180deg);
}

.avatar-advanced-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease;
}

.avatar-advanced-content.active {
    max-height: 500px;
}

.advanced-item {
    margin-bottom: 15px;
}

.advanced-label {
    display: block;
    margin-bottom: 8px;
    font-size: 0.95em;
    color: #5d8ab8;
    font-weight: 600;
}

.advanced-input,
.advanced-select {
    width: 100%;
    padding: 10px 15px;
    border: none;
    border-radius: 10px;
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    color: #4a6fa5;
    font-size: 0.95em;
    font-weight: 600;
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
    transition: all 0.3s ease;
    outline: none;
}

.advanced-input:focus,
.advanced-select:focus {
    box-shadow: inset 5px 5px 10px #ccd9e6, inset -5px -5px 10px #ffffff;
}

.advanced-input::placeholder {
    color: #a0b4c9;
}

.advanced-textarea {
    width: 100%;
    padding: 10px 15px;
    border: none;
    border-radius: 10px;
    background: linear-gradient(135deg, #ffffff, #e8f0f8);
    color: #4a6fa5;
    font-size: 0.95em;
    font-weight: 600;
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
    transition: all 0.3s ease;
    outline: none;
    resize: vertical;
    font-family: inherit;
    line-height: 1.6;
}

.advanced-textarea:focus {
    box-shadow: inset 5px 5px 10px #ccd9e6, inset -5px -5px 10px #ffffff;
}

.advanced-textarea::placeholder {
    color: #a0b4c9;
}

/* ========== 折叠侧边栏样式 ========== */

/* 侧边栏触发按钮 */
.sidebar-toggle {
    position: fixed;
    top: 20px;
    left: 20px;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, #e3edf7, #d4e6f9);
    border-radius: 16px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    cursor: pointer;
    z-index: 1001;
    box-shadow: 6px 6px 12px #b8bec8;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.sidebar-toggle:hover {
    transform: translateY(-2px);
    box-shadow: 8px 8px 16px #b8bec8;
}

.sidebar-toggle:active {
    transform: translateY(0);
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
}

.sidebar-toggle.active {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: opacity 0s, visibility 0s;
}

.toggle-line {
    width: 20px;
    height: 2.5px;
    background: #5d8ab8;
    border-radius: 2px;
    transition: all 0.25s ease;
}

.sidebar-toggle:hover .toggle-line {
    background: #7aa8d6;
    width: 22px;
}

.sidebar-toggle:active .toggle-line {
    width: 18px;
}

.sidebar-toggle.active .toggle-line {
    background: #ffffff;
}

.sidebar-toggle.active .toggle-line:nth-child(1) {
    transform: rotate(45deg) translate(6px, 6px);
}

.sidebar-toggle.active .toggle-line:nth-child(2) {
    opacity: 0;
    transform: translateX(-10px);
}

.sidebar-toggle.active .toggle-line:nth-child(3) {
    transform: rotate(-45deg) translate(6px, -6px);
}

/* 侧边栏遮罩层 */
.sidebar-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(74, 111, 165, 0.3);
    backdrop-filter: blur(3px);
    z-index: 999;
    opacity: 0;
    visibility: hidden;
    transition: all 0.3s ease;
}

.sidebar-overlay.active {
    opacity: 1;
    visibility: visible;
}

/* 侧边栏主体 */
.sidebar {
    position: fixed;
    top: 15px;
    left: 15px;
    width: 280px;
    height: calc(100% - 30px);
    background: linear-gradient(135deg, #e3edf7, #d4e6f9);
    z-index: 1000;
    transform: translateX(calc(-100% - 15px));
    transition: transform 0.35s cubic-bezier(0.4, 0, 0.2, 1) 0.05s;
    display: flex;
    flex-direction: column;
    border-radius: 30px;
    box-shadow: 12px 12px 24px #b8bec8;
}

.sidebar.active {
    transform: translateX(0);
}

/* 侧边栏头部 */
.sidebar-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 20px 24px;
    position: relative;
}

.sidebar-header::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 24px;
    right: 24px;
    height: 2px;
    background: rgba(93, 138, 184, 0.2);
    border-radius: 1px;
}

.sidebar-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.25em;
    font-weight: 700;
    color: #5d8ab8;
}

.sidebar-title-icon {
    font-size: 1.2em;
}

.sidebar-close {
    width: 32px;
    height: 32px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    border: none;
    border-radius: 50%;
    font-size: 1.4em;
    color: #5d8ab8;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 3px 3px 6px #b8bec8, -3px -3px 6px #ffffff;
    line-height: 1;
    transition: transform 0.25s ease, box-shadow 0.25s ease;
}

.sidebar-close:hover {
    transform: translateY(-2px);
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
}

.sidebar-close:active,
.sidebar-close.pressed {
    box-shadow: inset 2px 2px 4px #ccd9e6, inset -2px -2px 4px #ffffff;
}

/* 侧边栏内容区 */
.sidebar-content {
    flex: 1;
    padding: 24px;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
    align-items: stretch;
    justify-content: flex-start;
}

/* 空状态提示 */
.sidebar-empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 40px 20px;
    text-align: center;
}

.sidebar-empty-icon {
    font-size: 3em;
    margin-bottom: 16px;
    opacity: 0.6;
}

.sidebar-empty-text {
    font-size: 1em;
    color: #7aa8d6;
    font-weight: 600;
    margin-bottom: 8px;
}

.sidebar-empty-hint {
    font-size: 0.85em;
    color: #a0b4c9;
}

/* 侧边栏内容区滚动条 */
.sidebar-content::-webkit-scrollbar {
    width: 8px;
}

.sidebar-content::-webkit-scrollbar-track {
    background: #e3edf7;
    border-radius: 4px;
}

.sidebar-content::-webkit-scrollbar-thumb {
    background: linear-gradient(180deg, #c5d8f0, #a8c4e0);
    border-radius: 4px;
}

/* 响应式适配 */
@media (max-width: 768px) {
    .sidebar-toggle {
        top: 15px;
        left: 15px;
        width: 44px;
        height: 44px;
        border-radius: 14px;
    }

    .toggle-line {
        width: 18px;
        height: 2px;
    }

    .sidebar {
        width: 260px;
    }

    .sidebar-header {
        padding: 18px 16px;
    }

    .sidebar-title {
        font-size: 1.15em;
    }

    .sidebar-close {
        width: 30px;
        height: 30px;
        font-size: 1.25em;
    }

    .sidebar-content {
        padding: 18px;
    }
}

@media (max-width: 480px) {
    .sidebar-toggle {
        top: 12px;
        left: 12px;
        width: 40px;
        height: 40px;
        border-radius: 12px;
    }

    .toggle-line {
        width: 16px;
        height: 2px;
    }

    .sidebar {
        width: 240px;
    }

    .sidebar-header {
        padding: 16px 14px;
    }

    .sidebar-title {
        font-size: 1.1em;
    }

    .sidebar-close {
        width: 30px;
        height: 30px;
        font-size: 1.2em;
    }

    .sidebar-content {
        padding: 12px;
    }
}

/* ========== 侧边栏功能按钮样式 ========== */
.sidebar-menu {
    display: flex;
    flex-direction: column;
    gap: 12px;
    width: 100%;
    padding: 0;
    align-items: stretch;
}

.sidebar-menu-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    border: none;
    border-radius: 20px;
    cursor: pointer;
    font-size: 1em;
    font-weight: 600;
    color: #5d8ab8;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    text-align: left;
    width: 100%;
}

.sidebar-menu-item:hover {
    transform: translateY(-2px);
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
    background: linear-gradient(135deg, #f0f6fc, #e8f0f8);
}

.sidebar-menu-item:active {
    transform: translateY(0);
    box-shadow: inset 3px 3px 6px #ccd9e6, inset -3px -3px 6px #ffffff;
}

.sidebar-menu-icon {
    font-size: 1.4em;
    line-height: 1;
}

.sidebar-menu-text {
    flex: 1;
}

/* ========== 全屏 iframe 覆盖层样式 ========== */
.page-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 10002;
    background: linear-gradient(135deg, #e3edf7, #d4e6f9);
    display: none;
    animation: fadeIn 0.3s ease-out;
}

.page-overlay.active {
    display: block;
}

.page-overlay-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 24px;
    background: linear-gradient(135deg, #e3edf7, #d4e6f9);
    box-shadow: 0 4px 12px rgba(184, 190, 200, 0.3);
    position: relative;
    z-index: 1;
}

.page-overlay-title {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.2em;
    font-weight: 700;
    color: #5d8ab8;
    margin-left: 8px;
}

.page-overlay-title-icon {
    font-size: 1.3em;
}

.page-overlay-back {
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 10px 16px;
    background: linear-gradient(135deg, #e8f0f8, #d4e6f9);
    border: none;
    border-radius: 12px;
    font-size: 1em;
    font-weight: 600;
    color: #5d8ab8;
    cursor: pointer;
    box-shadow: 4px 4px 8px #b8bec8, -4px -4px 8px #ffffff;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

.page-overlay-back:hover {
    transform: translateY(-1px);
    box-shadow: 6px 6px 12px #b8bec8, -6px -6px 12px #ffffff;
    background: linear-gradient(135deg, #f0f6fc, #e8f0f8);
}

.page-overlay-back:active {
    transform: translateY(0);
    box-shadow: inset 2px 2px 4px #ccd9e6, inset -2px -2px 4px #ffffff;
}

.back-arrow {
    font-size: 1.2em;
    line-height: 1;
}

.back-text {
    font-size: 0.95em;
}

.page-overlay-iframe {
    width: 100%;
    height: calc(100% - 72px);
    border: none;
    background: #ffffff;
    /* 隐藏iframe滚动条 */
    scrollbar-width: none;
    -ms-overflow-style: none;
}

.page-overlay-iframe::-webkit-scrollbar {
    display: none;
}

/* 移动端适配 */
@media (max-width: 768px) {
    .sidebar-menu-item {
        padding: 14px 16px;
        font-size: 0.95em;
        border-radius: 16px;
    }

    .sidebar-menu-icon {
        font-size: 1.3em;
    }

    .page-overlay-header {
        padding: 12px 16px;
        gap: 12px;
    }

    .page-overlay-title {
        font-size: 1.1em;
    }

    .page-overlay-back {
        padding: 8px 12px;
        font-size: 0.9em;
    }

    .back-arrow {
        font-size: 1.1em;
    }

    .page-overlay-iframe {
        height: calc(100% - 56px);
    }
}

@media (max-width: 480px) {
    .sidebar-menu-item {
        padding: 12px 14px;
        font-size: 0.9em;
        border-radius: 14px;
    }

    .sidebar-menu-icon {
        font-size: 1.2em;
    }

    .page-overlay-header {
        padding: 10px 12px;
        gap: 10px;
    }

    .page-overlay-title {
        font-size: 1em;
    }

    .page-overlay-back {
        padding: 6px 10px;
        font-size: 0.85em;
    }

    .back-arrow {
        font-size: 1em;
    }

    .page-overlay-iframe {
        height: calc(100% - 48px);
    }
}