/* 全局样式 - 古风主题 */
:root {
    --primary-color: #8c5e58;
    --secondary-color: #a86b51;
    --accent-color: #7a5c61;
    --dark-color: #3c3530;
    --light-color: #f9f3ee;
    --paper-color: #f5ede3;
    --gray-color: #6c757d;
    --light-gray: #f1f3f4;
    --border-color: #d4c7b1;
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
    --border-radius: 0.5rem;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background-color: var(--light-color);
}

/* 滚动条样式 */
::-webkit-scrollbar {
    width: 8px;
    height: 8px;
}

::-webkit-scrollbar-track {
    background: var(--light-gray);
}

::-webkit-scrollbar-thumb {
    background: #c1c1c1;
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #a8a8a8;
}

/* 通用样式 */
.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1rem;
}

.section {
    padding: 4rem 0;
}

.section-title {
    font-size: clamp(1.5rem, 3vw, 2.5rem);
    font-weight: 700;
    color: var(--dark-color);
    margin-bottom: 1rem;
    text-align: center;
}

.section-subtitle {
    font-size: 1rem;
    color: var(--gray-color);
    text-align: center;
    max-width: 2xl;
    margin: 0 auto 3rem;
}

/* 按钮样式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 500;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    text-decoration: none;
    white-space: nowrap;
}

/* 粤语助手悬浮人物样式 */
#yueyu-assistant {
    transition: opacity 0.3s ease, transform 0.3s ease;
    opacity: 1;
    z-index: 50;
}

#yueyu-assistant:hover {
    transform: scale(1.1);
}

#yueyu-assistant.hidden {
    display: none;
}

.btn-primary {
    background-color: var(--primary-color);
    color: white;
}

.btn-primary:hover {
    background-color: rgba(232, 62, 140, 0.9);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background-color: rgba(111, 66, 193, 0.9);
    transform: translateY(-1px);
    box-shadow: var(--shadow-md);
}

.btn-outline {
    background-color: white;
    color: var(--primary-color);
    border: 1px solid var(--primary-color);
}

.btn-outline:hover {
    background-color: var(--light-gray);
}

.btn-gray {
    background-color: white;
    color: var(--gray-color);
    border: 1px solid var(--border-color);
}

.btn-gray:hover {
    background-color: var(--light-gray);
}

/* 卡片样式 */
.card {
    background-color: white;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.card-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.card-body {
    padding: 1.5rem;
}

.card-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 0.75rem;
}

/* 表单样式 */
.form-group {
    margin-bottom: 1.5rem;
}

.form-label {
    display: block;
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.form-control {
    width: 100%;
    padding: 0.75rem 1rem;
    font-size: 1rem;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.form-control:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(232, 62, 140, 0.1);
}

/* 导航栏样式 */
.navbar {
    position: sticky;
    top: 0;
    z-index: 50;
    background-color: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid var(--border-color);
    transition: var(--transition);
}

.navbar.scrolled {
    box-shadow: var(--shadow-md);
}

.navbar-brand {
    display: flex;
    align-items: center;
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    text-decoration: none;
}

.navbar-brand i {
    margin-right: 0.5rem;
}

.navbar-nav {
    display: flex;
    align-items: center;
    list-style: none;
}

.nav-item {
    margin-left: 1.5rem;
}

.nav-link {
    color: var(--gray-color);
    text-decoration: none;
    font-weight: 500;
    transition: var(--transition);
}

.nav-link:hover {
    color: var(--primary-color);
}

/* 视频卡片样式 */
.video-card {
    background-color: white;
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.video-card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
}

.video-card:hover .play-button {
    opacity: 1;
}

.video-thumbnail {
    position: relative;
    width: 100%;
    height: 200px;
    overflow: hidden;
}

.video-thumbnail img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: var(--transition);
}

.video-card:hover .video-thumbnail img {
    transform: scale(1.05);
}

.play-button {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 56px;
    height: 56px;
    background-color: rgba(255, 255, 255, 0.9);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary-color);
    font-size: 1.5rem;
    opacity: 0;
    transition: var(--transition);
    cursor: pointer;
}

.video-card-content {
    padding: 1rem;
}

.video-title {
    font-size: 1rem;
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
    transition: var(--transition);
}

.video-card:hover .video-title {
    color: var(--primary-color);
}

.video-meta {
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    color: var(--gray-color);
}

.video-category {
    position: absolute;
    top: 0.75rem;
    right: 0.75rem;
    padding: 0.25rem 0.5rem;
    background-color: var(--primary-color);
    color: white;
    font-size: 0.75rem;
    border-radius: 4px;
}

/* 练习区域样式 */
.exercise-container {
    background-color: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-md);
    overflow: hidden;
}

.exercise-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
}

.exercise-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--dark-color);
    margin-bottom: 0.5rem;
}

.exercise-description {
    color: var(--gray-color);
    font-size: 0.875rem;
}

.exercise-content {
    padding: 1.5rem;
}

/* 填空练习样式 */
.cloze-sentence {
    font-size: 1.125rem;
    line-height: 1.8;
    margin-bottom: 1.5rem;
    color: var(--dark-color);
}

.cloze-blank {
    display: inline-block;
    min-width: 60px;
    padding: 0.25rem 0.5rem;
    margin: 0 0.25rem;
    background-color: var(--light-gray);
    border: 2px dashed var(--border-color);
    border-radius: 4px;
    text-align: center;
    transition: var(--transition);
}

.cloze-blank.filled {
    background-color: rgba(232, 62, 140, 0.1);
    border-color: var(--primary-color);
    border-style: solid;
}

.cloze-options {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
    margin-bottom: 1.5rem;
}

.cloze-option {
    padding: 0.5rem 1rem;
    background-color: var(--light-gray);
    border: none;
    border-radius: 4px;
    cursor: pointer;
    transition: var(--transition);
    font-size: 0.875rem;
}

.cloze-option:hover:not(:disabled) {
    background-color: rgba(232, 62, 140, 0.1);
    color: var(--primary-color);
}

.cloze-option:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

/* 句子排序练习样式 */
.sentence-sorting-container {
    min-height: 200px;
    padding: 1.5rem;
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius);
    background-color: var(--light-gray);
    margin-bottom: 1.5rem;
}

.sentence-item {
    padding: 0.75rem 1rem;
    background-color: white;
    border-radius: 4px;
    box-shadow: var(--shadow-sm);
    margin-bottom: 0.75rem;
    cursor: move;
    transition: var(--transition);
}

.sentence-item:hover {
    box-shadow: var(--shadow-md);
}

.sentence-item.dragging {
    opacity: 0.5;
    transform: rotate(2deg);
}

/* 进度条样式 */
.progress-container {
    margin-top: 1.5rem;
}

.progress-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.5rem;
}

.progress-label {
    font-size: 0.75rem;
    color: var(--gray-color);
}

.progress-bar {
    width: 100%;
    height: 10px;
    background-color: var(--light-gray);
    border-radius: 5px;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

/* 模态框样式 */
.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 100;
    opacity: 0;
    visibility: hidden;
    transition: var(--transition);
}

.modal.active {
    opacity: 1;
    visibility: visible;
}

.modal-content {
    background-color: white;
    border-radius: var(--border-radius);
    width: 100%;
    max-width: 600px;
    max-height: 90vh;
    overflow-y: auto;
    transform: translateY(20px);
    transition: var(--transition);
}

.modal.active .modal-content {
    transform: translateY(0);
}

.modal-header {
    padding: 1.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.modal-title {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--dark-color);
}

.modal-close {
    background: none;
    border: none;
    font-size: 1.25rem;
    color: var(--gray-color);
    cursor: pointer;
    transition: var(--transition);
}

.modal-close:hover {
    color: var(--dark-color);
}

.modal-body {
    padding: 1.5rem;
}

.modal-footer {
    padding: 1.5rem;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
}

/* 加载动画 */
.loader {
    display: inline-block;
    width: 20px;
    height: 20px;
    border: 3px solid var(--light-gray);
    border-radius: 50%;
    border-top-color: var(--primary-color);
    animation: spin 1s ease-in-out infinite;
}

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

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar-nav {
        display: none;
    }
    
    .mobile-menu-button {
        display: block;
    }
    
    .video-grid {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        margin: 1rem;
    }
}

@media (min-width: 769px) {
    .mobile-menu-button {
        display: none;
    }
    
    .video-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
}

@media (min-width: 1024px) {
    .video-grid {
        grid-template-columns: repeat(3, 1fr);
    }
}

/* 动画效果 */
@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes slideIn {
    from {
        transform: translateX(-20px);
        opacity: 0;
    }
    to {
        transform: translateX(0);
        opacity: 1;
    }
}

@keyframes float {
    0% {
        transform: translateY(0);
    }
    50% {
        transform: translateY(-10px);
    }
    100% {
        transform: translateY(0);
    }
}

.fade-in {
    animation: fadeIn 0.5s ease forwards;
}

.slide-in {
    animation: slideIn 0.5s ease forwards;
}

.floating {
    animation: float 3s ease-in-out infinite;
}

/* 延迟动画 */
.delay-100 {
    animation-delay: 0.1s;
}

.delay-200 {
    animation-delay: 0.2s;
}

.delay-300 {
    animation-delay: 0.3s;
}

.delay-400 {
    animation-delay: 0.4s;
}

.delay-500 {
    animation-delay: 0.5s;
}

/* 古风装饰 */
.chinese-pattern {
    position: relative;
}

.chinese-pattern::before,
.chinese-pattern::after {
    content: "✦";
    color: var(--primary-color);
    opacity: 0.7;
    position: absolute;
    font-size: 1rem;
}

.chinese-pattern::before {
    left: -1.5rem;
    top: 50%;
    transform: translateY(-50%);
}

.chinese-pattern::after {
    right: -1.5rem;
    top: 50%;
    transform: translateY(-50%);
}

/* 答案解答样式 */
.answer-container {
    background-color: var(--paper-color);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-top: 1.5rem;
    position: relative;
    box-shadow: var(--shadow-md);
}

.answer-container::before {
    content: '';
    position: absolute;
    top: -8px;
    left: 20px;
    width: 16px;
    height: 16px;
    background-color: var(--paper-color);
    border-top: 2px solid var(--border-color);
    border-left: 2px solid var(--border-color);
    transform: rotate(45deg);
}

.answer-title {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-family: var(--gushi-font);
}

.answer-content {
    font-size: 1rem;
    line-height: 1.8;
    color: var(--dark-color);
}

.answer-content strong {
    font-size: 1.125rem;
    color: var(--primary-color);
}

/* 粤语助手悬浮人物样式 */
#yueyu-assistant {
    transition: opacity 0.3s ease, transform 0.3s ease;
    opacity: 1;
    z-index: 50;
}

#yueyu-assistant:hover {
    transform: scale(1.1);
}

#yueyu-assistant.hidden {
    display: none;
}