:root {
    --primary: #0066ff;
    --primary-dark: #0052cc;
    --primary-light: #4d94ff;
    --secondary: #00cc99;
    --accent: #ff6b6b;
    --dark: #0a0a1a;
    --dark-light: #1a1a2e;
    --light: #f0f4fa;
    --gray: #8a9bb5;
    
    /* 仪表盘专用变量 */
    --primary-color: #0066ff;
    --bg-primary: #0a0a1a;
    --card-bg: rgba(255, 255, 255, 0.03);
    --text-color: #f0f4fa;
    --text-secondary: #8a9bb5;
    --border-color: rgba(255, 255, 255, 0.1);
    
    --gradient-1: linear-gradient(135deg, #0066ff, #00cc99);
    --gradient-2: linear-gradient(45deg, #ff6b6b, #ffb347);
    --gradient-3: linear-gradient(135deg, #667eea, #764ba2);
    
    --shadow-sm: 0 2px 4px 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);
    --shadow-xl: 0 20px 25px rgba(0,0,0,0.1);
    --shadow-glow: 0 0 20px rgba(0,102,255,0.3);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, sans-serif;
    background: var(--dark);
    color: var(--light);
    line-height: 1.6;
    overflow-x: hidden;
}

/* 动态背景 */
.dynamic-bg {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    overflow: hidden;
}

.binary-rain {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
}

.binary-drop {
    position: absolute;
    color: rgba(0, 102, 255, 0.1);
    font-family: 'Courier New', monospace;
    font-size: 14px;
    white-space: nowrap;
    animation: rain linear infinite;
    writing-mode: vertical-rl;
    text-orientation: upright;
}

@keyframes rain {
    0% { transform: translateY(-100%); opacity: 0; }
    10% { opacity: 0.3; }
    90% { opacity: 0.3; }
    100% { transform: translateY(100vh); opacity: 0; }
}

.glow-sphere {
    position: absolute;
    width: 500px;
    height: 500px;
    border-radius: 50%;
    filter: blur(100px);
    pointer-events: none;
    opacity: 0.3;
}

.sphere-1 {
    top: -200px;
    left: -200px;
    background: var(--primary);
    animation: pulse 10s ease-in-out infinite;
}

.sphere-2 {
    bottom: -200px;
    right: -200px;
    background: var(--secondary);
    animation: pulse 10s ease-in-out infinite reverse;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.3; }
    50% { transform: scale(1.2); opacity: 0.5; }
}

/* 导航栏 */
.navbar {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(10, 10, 26, 0.8);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 1.5rem;
    font-weight: bold;
}

.nav-logo i {
    color: var(--primary);
    animation: spin 10s linear infinite;
}

@keyframes spin {
    from { transform: rotate(0deg); }
    to { transform: rotate(360deg); }
}

.nav-links {
    display: flex;
    gap: 2rem;
}

.nav-link {
    color: var(--light);
    text-decoration: none;
    padding: 0.5rem 1rem;
    border-radius: 5px;
    transition: all 0.3s;
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    width: 0;
    height: 2px;
    background: var(--gradient-1);
    transition: all 0.3s;
    transform: translateX(-50%);
}

.nav-link:hover::after {
    width: 80%;
}

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

/* 按钮 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 0.5rem 1.5rem;
    border-radius: 50px;
    font-weight: 500;
    text-decoration: none;
    transition: all 0.3s;
    border: none;
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}

.btn:hover::before {
    left: 100%;
}

.btn-primary {
    background: var(--gradient-1);
    color: white;
    box-shadow: 0 0 20px rgba(0,102,255,0.3);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 0 30px rgba(0,102,255,0.5);
}

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

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

.btn-accent {
    background: var(--gradient-2);
    color: white;
}

.btn-large {
    padding: 1rem 2rem;
    font-size: 1.2rem;
}

/* 英雄区域 */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: space-between;
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
    position: relative;
}

.hero-content {
    flex: 1;
    max-width: 600px;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    background: rgba(255,255,255,0.1);
    backdrop-filter: blur(5px);
    border: 1px solid rgba(255,255,255,0.2);
    padding: 0.5rem 1.5rem;
    border-radius: 50px;
    margin-bottom: 2rem;
    color: var(--primary-light);
}

.hero-title {
    font-size: 4rem;
    margin-bottom: 1rem;
    line-height: 1.2;
}

.gradient-text {
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    font-size: 5rem;
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--gray);
    margin-bottom: 2rem;
}

.hero-stats {
    display: flex;
    gap: 3rem;
    margin-bottom: 2rem;
}

.stat-item {
    text-align: center;
}

.stat-number {
    display: block;
    font-size: 2rem;
    font-weight: bold;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.stat-label {
    color: var(--gray);
    font-size: 0.9rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
}

/* 3D立方体 */
.hero-3d {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    perspective: 1000px;
}

.floating-cube {
    width: 200px;
    height: 200px;
    position: relative;
    transform-style: preserve-3d;
    animation: cubeRotate 20s infinite linear;
}

@keyframes cubeRotate {
    from { transform: rotateX(0deg) rotateY(0deg); }
    to { transform: rotateX(360deg) rotateY(360deg); }
}

.cube-face {
    position: absolute;
    width: 200px;
    height: 200px;
    background: rgba(0,102,255,0.2);
    border: 2px solid var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    font-weight: bold;
    color: white;
    backdrop-filter: blur(5px);
}

.cube-face.front { transform: translateZ(100px); }
.cube-face.back { transform: rotateY(180deg) translateZ(100px); }
.cube-face.right { transform: rotateY(90deg) translateZ(100px); }
.cube-face.left { transform: rotateY(-90deg) translateZ(100px); }
.cube-face.top { transform: rotateX(90deg) translateZ(100px); }
.cube-face.bottom { transform: rotateX(-90deg) translateZ(100px); }

/* 特色卡片 */
.features-section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 3rem;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.section-title i {
    color: var(--primary);
    margin: 0 0.5rem;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 2rem;
}

.feature-card {
    background: rgba(255,255,255,0.05);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 20px;
    padding: 2rem;
    transition: all 0.3s;
    position: relative;
    overflow: hidden;
}

.feature-card:hover {
    transform: translateY(-10px);
    border-color: var(--primary);
    box-shadow: var(--shadow-glow);
}

.feature-card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(0,102,255,0.1) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.5s;
}

.feature-card:hover::before {
    opacity: 1;
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin-bottom: 1.5rem;
    background: var(--gradient-1);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    position: relative;
    overflow: hidden;
}

.feature-icon::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(45deg, transparent, rgba(255,255,255,0.3), transparent);
    animation: shine 3s infinite;
}

@keyframes shine {
    0% { transform: translateX(-100%) translateY(-100%); }
    100% { transform: translateX(100%) translateY(100%); }
}

.feature-card h3 {
    margin-bottom: 1rem;
}

.feature-card p {
    color: var(--gray);
    margin-bottom: 1rem;
}

.feature-preview {
    margin-top: 1rem;
    border-radius: 10px;
    overflow: hidden;
}

.feature-preview img,
.feature-preview video {
    width: 100%;
    height: auto;
}

/* 知识点区域 */
.topics-preview-section {
    max-width: 1200px;
    margin: 0 auto;
    margin-bottom: 8rem;
    padding: 4rem 2rem;
    min-height: 900px;
    overflow: visible;
}

/* 联系区域 */
.contact-section {
    background: linear-gradient(135deg, rgba(0,102,255,0.1), rgba(0,204,153,0.1));
    padding: 4rem 2rem;
    margin-top: 10rem;
    position: relative;
    z-index: 1;
}

.papers-tabs {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
}

.paper-tab {
    padding: 0.75rem 2rem;
    background: transparent;
    border: 1px solid rgba(255,255,255,0.2);
    color: var(--gray);
    border-radius: 50px;
    cursor: pointer;
    transition: all 0.3s;
    font-size: 1rem;
}

.paper-tab:hover,
.paper-tab.active {
    background: var(--gradient-1);
    color: white;
    border-color: transparent;
}

.topics-mindmap {
    height: 600px;
    background: rgba(0,0,0,0.2);
    border-radius: 20px;
    margin-bottom: 2rem;
    position: relative;
    overflow: auto;
}

/* 真题区域 */
.papers-section {
    max-width: 1200px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

.papers-filter {
    display: flex;
    gap: 1rem;
    margin-bottom: 2rem;
    flex-wrap: wrap;
}

.papers-filter select {
    padding: 0.75rem 1.5rem;
    background: rgba(255,255,255,0.1);
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: 50px;
    color: var(--light);
    font-size: 1rem;
    cursor: pointer;
    flex: 1;
    min-width: 150px;
}

.papers-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 2rem;
}

.paper-card {
    background: rgba(255,255,255,0.05);
    border: 1px solid rgba(255,255,255,0.1);
    border-radius: 15px;
    padding: 1.5rem;
    transition: all 0.3s;
    cursor: pointer;
}

.paper-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary);
}

.paper-card.loading {
    animation: pulse 1.5s infinite;
}

.paper-year {
    font-size: 2rem;
    font-weight: bold;
    color: var(--primary);
    margin-bottom: 0.5rem;
}

.paper-title {
    font-size: 1.2rem;
    margin-bottom: 1rem;
}

.paper-meta {
    display: flex;
    gap: 1rem;
    color: var(--gray);
    font-size: 0.9rem;
}

/* 学习流程 */
.workflow-section {
    max-width: 1200px;
    margin: 0 auto;
    margin-top: 3rem;
    padding: 4rem 2rem;
}

.workflow-timeline {
    position: relative;
    max-width: 800px;
    margin: 0 auto;
}

.workflow-timeline::before {
    content: '';
    position: absolute;
    left: 50px;
    top: 0;
    bottom: 0;
    width: 2px;
    background: var(--gradient-1);
}

.timeline-item {
    display: flex;
    gap: 2rem;
    margin-bottom: 3rem;
    position: relative;
}

.timeline-number {
    width: 100px;
    height: 100px;
    background: var(--gradient-1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 2rem;
    font-weight: bold;
    box-shadow: var(--shadow-glow);
    z-index: 1;
}

.timeline-content {
    flex: 1;
    padding: 1rem;
}

.timeline-content h3 {
    margin-bottom: 0.5rem;
    color: var(--primary-light);
}

/* 联系区域 */
.contact-section {
    background: linear-gradient(135deg, rgba(0,102,255,0.1), rgba(0,204,153,0.1));
    padding: 4rem 2rem;
    margin-top: 4rem;
}

.contact-container {
    max-width: 800px;
    margin: 0 auto;
    text-align: center;
}

.contact-container h2 {
    font-size: 2.5rem;
    margin-bottom: 1rem;
}

.contact-info {
    display: flex;
    justify-content: center;
    gap: 3rem;
    margin: 2rem 0;
    flex-wrap: wrap;
}

.info-item {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--gray);
}

.info-item i {
    color: var(--primary);
}

/* 页脚 */
.footer {
    background: rgba(0,0,0,0.5);
    border-top: 1px solid rgba(255,255,255,0.1);
    padding: 4rem 0 2rem;
}

.footer-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
}

.footer-section h4 {
    margin-bottom: 1rem;
    color: var(--primary-light);
}

.footer-section a {
    display: block;
    color: var(--gray);
    text-decoration: none;
    margin-bottom: 0.5rem;
    transition: color 0.3s;
}

.footer-section a:hover {
    color: var(--primary);
}

.footer-section p {
    color: var(--gray);
    margin-bottom: 0.5rem;
}

.social-links {
    display: flex;
    gap: 1rem;
}

.social-links a {
    width: 40px;
    height: 40px;
    border: 1px solid rgba(255,255,255,0.2);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s;
}

.social-links a:hover {
    background: var(--primary);
    border-color: transparent;
}

.footer-bottom {
    text-align: center;
    padding-top: 2rem;
    margin-top: 2rem;
    border-top: 1px solid rgba(255,255,255,0.1);
    color: var(--gray);
}

/* 响应式设计 */
@media (max-width: 768px) {
    .hero {
        flex-direction: column;
        text-align: center;
    }
    
    .hero-title {
        font-size: 3rem;
    }
    
    .gradient-text {
        font-size: 4rem;
    }
    
    .hero-stats {
        justify-content: center;
    }
    
    .hero-buttons {
        justify-content: center;
    }
    
    .nav-container {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-links {
        flex-wrap: wrap;
        justify-content: center;
    }
    
    .workflow-timeline::before {
        left: 30px;
    }
    
    .timeline-number {
        width: 60px;
        height: 60px;
        font-size: 1.5rem;
    }
}

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

.fade-in-up {
    animation: fadeInUp 0.6s ease-out;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-20px); }
}

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