:root {
    --primary-color: #0a0a1a;
    --secondary-color: #15152a;
    --accent-color: #8a2be2;
    --accent-secondary: #ff3e78;
    --accent-gradient: linear-gradient(135deg, #8a2be2 0%, #ff3e78 100%);
    --neon-glow: 0 0 10px rgba(138, 43, 226, 0.5), 0 0 20px rgba(255, 62, 120, 0.3);
    --text-color: #f0f0ff;
    --border-color: #2a2a40;
    --hover-color: #1d1d35;
    --shadow-color: rgba(138, 43, 226, 0.25);
    --glass-effect: rgba(255, 255, 255, 0.07);
}

body {
    font-family: 'Segoe UI', 'Microsoft YaHei', sans-serif;
    margin: 0;
    padding: 0;
    background-color: var(--primary-color);
    color: var(--text-color);
    line-height: 1.6;
    height: 100vh;
    overflow: hidden;
    opacity: 0;
    transition: opacity 0.5s ease;
}

body.loaded {
    opacity: 1;
}

.container-fluid {
    display: flex;
    height: 100vh;
    padding: 0;
}

/* 简化了侧边栏和内容区域的样式 */
.sidebar, .content {
    position: relative;
    height: 100vh;
    overflow: hidden;
}

.sidebar {
    width: 280px;
    background-color: var(--secondary-color);
    background-image: radial-gradient(circle at top right, rgba(138, 43, 226, 0.15), transparent 70%);
    display: flex;
    flex-direction: column;
    border-right: 1px solid var(--border-color);
    box-shadow: 5px 0 25px rgba(0, 0, 0, 0.2);
    z-index: 2;
}

.content {
    flex: 1;
    background-color: #000;
    background-image: radial-gradient(circle at bottom left, rgba(255, 62, 120, 0.1), transparent 70%);
}

/* 导航按钮样式 - 更现代化设计 */
.nav-pills {
    padding: 0.8rem 0.5rem;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    background-color: rgba(21, 21, 42, 0.8);
    backdrop-filter: blur(15px);
    -webkit-backdrop-filter: blur(15px);
    position: sticky;
    top: 0;
    z-index: 10;
}

.nav-pills .nav-link {
    color: var(--text-color);
    border-radius: 14px;
    transition: all 0.3s ease;
    background-color: rgba(138, 43, 226, 0.1);
    padding: 0.6rem 0.8rem;
    margin: 0 3px;
    font-size: 0.9rem;
    font-weight: 600;
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
    min-width: 80px;
    width: 33%;
    text-align: center;
    letter-spacing: 0.5px;
    will-change: transform, box-shadow;
}

.nav-pills .nav-link:before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 0;
    height: 100%;
    background: var(--accent-gradient);
    opacity: 0.3;
    transition: width 0.3s ease;
    z-index: -1;
}

.nav-pills .nav-link:hover {
    background-color: var(--hover-color);
    border-color: var(--accent-color);
    transform: translateY(-3px);
    box-shadow: 0 0 10px rgba(138, 43, 226, 0.3);
}

.nav-pills .nav-link:hover:before {
    width: 100%;
}

.nav-pills .nav-link.active {
    background: var(--accent-gradient);
    color: white;
    box-shadow: 0 0 10px rgba(138, 43, 226, 0.3);
    transform: translateY(-3px);
}

/* 课程容器样式 - 修复闪光问题 */
.course-containers {
    flex: 1;
    overflow: hidden;
    display: flex;
    padding: 5px;
}

.course-container {
    display: none;
    flex: 1;
    overflow: hidden;
    flex-direction: column;
    opacity: 0;
    transform: translateY(10px);
    transition: opacity 0.3s ease, transform 0.3s ease;
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.course-container.active {
    display: flex;
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
    position: relative;
}

/* 课程列表和课程导航样式 - 增强视觉效果 */
.course-list {
    flex: 1;
    overflow-y: auto;
    padding: 0.5rem;
    scrollbar-width: thin;
    scrollbar-color: var(--accent-color) var(--secondary-color);
}

.lesson-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.lesson-item {
    margin-bottom: 12px;
    border-radius: 16px;
    overflow: hidden;
    background-color: rgba(15, 15, 30, 0.5);
    backdrop-filter: blur(10px);
    -webkit-backdrop-filter: blur(10px);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.15);
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
    border: 1px solid rgba(138, 43, 226, 0.1);
    will-change: transform, box-shadow;
}

.lesson-item:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.2), 0 0 10px rgba(138, 43, 226, 0.3);
    border-color: rgba(138, 43, 226, 0.3);
}

.lesson-header {
    background-color: var(--hover-color);
    color: var(--text-color);
    padding: 14px 16px;
    font-weight: bold;
    cursor: pointer;
    position: relative;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    border-left: 3px solid var(--accent-color);
    border-top-left-radius: 12px;
    border-top-right-radius: 12px;
}

.lesson-header:hover {
    color: var(--accent-secondary);
}

.lesson-header::after {
    content: '\25BC';
    position: absolute;
    right: 15px;
    transition: transform 0.4s cubic-bezier(0.68, -0.55, 0.27, 1.55);
    font-size: 0.8rem;
    color: var(--accent-color);
}

.lesson-header.expanded::after {
    transform: rotate(180deg);
}

/* 简化episode相关样式 */
.episode-list {
    list-style: none;
    padding: 0;
    margin: 0;
    border-top: 1px solid var(--border-color);
    overflow: hidden;
    max-height: 0;
    transition: max-height 0.4s cubic-bezier(0.165, 0.84, 0.44, 1);
}

.episode-list.show {
    max-height: 500px;
}

.episode-item {
    padding: 10px 15px 10px 20px;
    border-bottom: 1px solid var(--border-color);
    cursor: pointer;
    transition: all 0.3s ease;
    position: relative;
    display: flex;
    align-items: center;
    border-radius: 6px;
}

.episode-item:before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    height: 100%;
    width: 0;
    background: var(--accent-gradient);
    opacity: 0.2;
    transition: width 0.3s ease;
}

.episode-item:last-child {
    border-bottom: none;
}

.episode-item:hover {
    background-color: var(--hover-color);
    padding-left: 25px;
}

.episode-item:hover:before {
    width: 5px;
}

.episode-item.selected {
    background-color: rgba(138, 43, 226, 0.2);
    color: white;
    font-weight: 500;
}

.episode-item.selected:before {
    width: 5px;
}

/* 视频播放器样式 - 简化 */
.video-player {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    background-color: #000;
    overflow: hidden;
}

.video-player iframe, #vimeoPlayer {
    width: 100%;
    height: 100%;
    border: none;
    opacity: 0;
    transform: scale(0.98);
    transition: all 0.5s ease;
}

.video-player iframe.loaded, #vimeoPlayer.loaded {
    opacity: 1;
    transform: scale(1);
}

.course-title {
    padding: 1rem;
    margin: 0;
    background-color: var(--secondary-color);
    border-bottom: 1px solid var(--border-color);
}

.message {
    text-align: center;
    padding: 2rem;
    color: var(--text-color);
    font-size: 1.2rem;
    opacity: 0.8;
    text-shadow: var(--neon-glow);
}

/* 课程链接按钮样式 - 更现代化 */
.course-link-btn {
    position: absolute;
    top: 20px;
    right: 20px;
    z-index: 100;
    background: var(--accent-gradient);
    color: white;
    border: none;
    border-radius: 14px;
    padding: 10px 18px;
    display: none;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
    letter-spacing: 0.5px;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.2);
    backdrop-filter: blur(5px);
    -webkit-backdrop-filter: blur(5px);
    opacity: 0;
    transform: translateY(-10px);
    text-decoration: none;
}

.course-link-btn.show {
    opacity: 1;
    transform: translateY(0);
}

.course-link-btn:hover {
    transform: translateY(-5px);
    box-shadow: 0 8px 25px rgba(0, 0, 0, 0.3), var(--neon-glow);
}

.course-link-btn i {
    margin-right: 8px;
}

/* 滚动条样式 - 更简洁 */
.course-list::-webkit-scrollbar {
    width: 6px;
}

.course-list::-webkit-scrollbar-track {
    background: var(--secondary-color);
    border-radius: 3px;
}

.course-list::-webkit-scrollbar-thumb {
    background: var(--accent-gradient);
    border-radius: 3px;
}

.selected {
    background-color: var(--accent-color) !important;
}

.divider {
    height: 1px;
    background-color: var(--border-color);
    margin: 0;
}

/* 波纹和加载动画 */
.ripple {
    position: absolute;
    border-radius: 50%;
    background-color: rgba(255, 255, 255, 0.3);
    transform: scale(0);
    animation: ripple 0.6s linear;
    pointer-events: none;
}

@keyframes ripple {
    to {
        transform: scale(4);
        opacity: 0;
    }
}

/* 简化预加载器样式 */
.preloader {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--primary-color);
    z-index: 9999;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.5s ease;
}

body.loaded .preloader {
    opacity: 0;
    visibility: hidden;
}

.loader {
    display: flex;
    justify-content: center;
    align-items: center;
}

.loader .circle {
    width: 20px;
    height: 20px;
    margin: 0 10px;
    border-radius: 50%;
    background: var(--accent-gradient);
    animation: loader 1.5s ease-in-out infinite;
    box-shadow: var(--neon-glow);
}

.loader .circle:nth-child(1) {
    animation-delay: 0s;
}

.loader .circle:nth-child(2) {
    animation-delay: 0.15s;
}

.loader .circle:nth-child(3) {
    animation-delay: 0.3s;
}

@keyframes loader {
    0%, 100% {
        transform: translateY(0) scale(1);
    }
    40% {
        transform: translateY(-20px) scale(1.2);
    }
}

/* 粒子背景 */
#particles-js {
    position: fixed;
    width: 100%;
    height: 100%;
    top: 0;
    left: 0;
    z-index: -1;
    pointer-events: none;
}

/* 加载指示器样式 */
.loading-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--text-color);
    padding: 20px;
    text-align: center;
}

.spinner {
    width: 40px;
    height: 40px;
    border: 3px solid rgba(138, 43, 226, 0.2);
    border-radius: 50%;
    border-top-color: var(--accent-color);
    animation: spin 1s ease-in-out infinite;
    margin-bottom: 15px;
    box-shadow: var(--neon-glow);
}

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

/* 媒体查询 - 移动端适配 */
@media (max-width: 768px) {
    .container-fluid {
        flex-direction: column;
    }
    
    .sidebar {
        width: 100%;
        height: 50vh;
        border-right: none;
        border-bottom: 1px solid var(--border-color);
    }
    
    .content {
        height: 50vh;
    }
    
    .nav-pills .nav-link {
        font-size: 0.8rem;
        padding: 0.5rem 0.6rem;
    }
    
    .lesson-header {
        padding: 10px 12px;
        font-size: 0.9rem;
    }
    
    .episode-item {
        padding: 8px 12px 8px 15px;
        font-size: 0.85rem;
    }
    
    .course-link-btn {
        top: 10px;
        right: 10px;
        padding: 8px 14px;
        font-size: 0.85rem;
    }
}

/* 针对小屏幕设备的额外适配 */
@media (max-width: 480px) {
    .sidebar {
        height: 45vh;
    }
    
    .content {
        height: 55vh;
    }
    
    .nav-pills {
        padding: 0.6rem 0.4rem;
    }
    
    .nav-pills .nav-link {
        min-width: 60px;
        font-size: 0.75rem;
        padding: 0.4rem 0.5rem;
    }
    
    .lesson-item {
        margin-bottom: 8px;
    }
    
    .lesson-header {
        padding: 8px 10px;
        font-size: 0.85rem;
    }
    
    .episode-item {
        padding: 6px 10px 6px 12px;
        font-size: 0.8rem;
    }
}

/* 触摸设备的交互优化 */
@media (hover: none) {
    .nav-pills .nav-link {
        -webkit-tap-highlight-color: transparent;
    }
    
    .nav-pills .nav-link:active {
        background-color: var(--hover-color);
        transform: scale(0.98);
    }
    
    .lesson-header:active,
    .episode-item:active {
        background-color: var(--hover-color);
    }
    
    .episode-item:active:before {
        width: 5px;
    }
    
    .course-list {
        -webkit-overflow-scrolling: touch;
        touch-action: pan-y;
    }
    
    .episode-list.show {
        /* 增加移动端的最大高度，防止内容被截断 */
        max-height: 800px;
    }
}