/* CSS 变量定义 */
:root {
    --primary-color: #3498db;
    --secondary-color: #e74c3c;
    --accent-color: #2ecc71;
    --dark-color: #2c3e50;
    --light-color: #ecf0f1;
    --gradient-1: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --gradient-2: linear-gradient(45deg, #ff6b6b, #4ecdc4);
    --gradient-3: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    --shadow-light: 0 4px 6px rgba(0, 0, 0, 0.1);
    --shadow-medium: 0 8px 25px rgba(0, 0, 0, 0.15);
    --shadow-heavy: 0 15px 35px rgba(0, 0, 0, 0.2);
    --border-radius: 12px;
    --animation-duration: 0.3s;
    --animation-easing: cubic-bezier(0.25, 0.8, 0.25, 1);
}

/* 基础样式重置 */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
    background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
    overflow-x: hidden;
}

/* 容器样式 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 头部导航 */
.header {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(255, 255, 255, 0.2);
    z-index: 1000;
    transition: all var(--animation-duration) var(--animation-easing);
}

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

.nav-brand h1 {
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 2rem;
}

.nav-menu a {
    text-decoration: none;
    color: var(--dark-color);
    font-weight: 500;
    transition: all var(--animation-duration) var(--animation-easing);
    position: relative;
}

.nav-menu a::after {
    content: '';
    position: absolute;
    bottom: -5px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary-color);
    transition: width var(--animation-duration) var(--animation-easing);
}

.nav-menu a:hover::after {
    width: 100%;
}

.nav-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
}

.nav-toggle span {
    width: 25px;
    height: 3px;
    background: var(--dark-color);
    margin: 3px 0;
    transition: 0.3s;
}

/* 主要内容区域 */
.main {
    margin-top: 80px;
}

/* 英雄区域 */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    color: white;
    text-align: center;
    overflow: hidden;
}

.hero-content {
    z-index: 2;
    max-width: 600px;
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 700;
    margin-bottom: 1rem;
    opacity: 0;
    animation: fadeInUp 1s ease-out forwards;
}

.hero-subtitle {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    opacity: 0;
    animation: fadeInUp 1s ease-out 0.3s forwards;
}

.hero-btn {
    padding: 15px 30px;
    font-size: 1.1rem;
    background: rgba(255, 255, 255, 0.2);
    border: 2px solid rgba(255, 255, 255, 0.3);
    border-radius: var(--border-radius);
    color: white;
    cursor: pointer;
    transition: all var(--animation-duration) var(--animation-easing);
    backdrop-filter: blur(10px);
    opacity: 0;
    animation: fadeInUp 1s ease-out 0.6s forwards;
}

.hero-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.2);
}

.hero-visual {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 1;
}

.floating-elements {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 200px;
    height: 200px;
}

.float-item {
    position: absolute;
    width: 60px;
    height: 60px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    animation: float 6s ease-in-out infinite;
}

.float-item:nth-child(1) {
    top: 0;
    left: 0;
    animation-delay: 0s;
}

.float-item:nth-child(2) {
    top: 0;
    right: 0;
    animation-delay: 2s;
}

.float-item:nth-child(3) {
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    animation-delay: 4s;
}

/* 特性展示区域 */
.features {
    padding: 80px 0;
    background: var(--light-color);
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 3rem;
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.demo-section {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 40px;
    margin-bottom: 60px;
    background: white;
    border-radius: var(--border-radius);
    overflow: hidden;
    box-shadow: var(--shadow-medium);
    transition: transform var(--animation-duration) var(--animation-easing);
}

.demo-section:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-heavy);
}

.demo-code, .demo-effect {
    padding: 30px;
}

.demo-code {
    background: #f8f9fa;
    border-right: 1px solid #e9ecef;
}

.demo-code h3, .demo-effect h3 {
    margin-bottom: 20px;
    font-size: 1.3rem;
    color: var(--dark-color);
}

.demo-code pre {
    background: #2d3748;
    color: #e2e8f0;
    padding: 20px;
    border-radius: 8px;
    overflow-x: auto;
    font-size: 0.9rem;
    line-height: 1.5;
}

.demo-code code {
    font-family: 'Fira Code', 'Monaco', monospace;
}

/* Grid 演示效果 */
.grid-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    padding: 20px;
}

.grid-item {
    background: var(--gradient-1);
    border-radius: var(--border-radius);
    padding: 20px;
    color: white;
    text-align: center;
    font-weight: 500;
    transition: transform var(--animation-duration) var(--animation-easing);
}

.grid-item:hover {
    transform: translateY(-5px);
}

/* 动画卡片 */
.animated-card {
    background: var(--primary-color);
    animation: pulse 2s infinite;
    border-radius: 15px;
    padding: 30px;
    color: white;
    text-align: center;
    transition: all var(--animation-duration) var(--animation-easing);
}

.color-switch {
    margin-top: 15px;
    padding: 10px 20px;
    background: rgba(255, 255, 255, 0.2);
    border: 1px solid rgba(255, 255, 255, 0.3);
    border-radius: 8px;
    color: white;
    cursor: pointer;
    transition: all var(--animation-duration) var(--animation-easing);
}

.color-switch:hover {
    background: rgba(255, 255, 255, 0.3);
}

/* Flexbox 演示 */
.flex-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
    padding: 20px;
}

.flex-item {
    flex: 1 1 150px;
    min-height: 100px;
    background: var(--gradient-2);
    border-radius: 10px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: 500;
    transition: transform var(--animation-duration) var(--animation-easing);
}

.flex-item:hover {
    transform: scale(1.05);
}

/* JavaScript 演示 */
.js-demo {
    text-align: center;
}

#particle-canvas {
    border: 2px solid #ddd;
    border-radius: 8px;
    background: #f8f9fa;
    display: block;
    margin: 0 auto 20px;
}

#particle-btn {
    padding: 12px 24px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-size: 1rem;
    transition: all var(--animation-duration) var(--animation-easing);
}

#particle-btn:hover {
    background: #2980b9;
    transform: translateY(-2px);
}

/* 现代卡片效果 */
.modern-card {
    background: var(--gradient-3);
    border-radius: 20px;
    backdrop-filter: blur(10px);
    box-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.37);
    padding: 25px;
    color: white;
    transition: all var(--animation-duration) var(--animation-easing);
}

.modern-card:hover {
    transform: translateY(-10px) scale(1.02);
    box-shadow: 0 15px 40px 0 rgba(31, 38, 135, 0.5);
}

.modern-card h4 {
    margin-bottom: 15px;
    font-size: 1.3rem;
}

.glass-effect {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 10px;
    padding: 15px;
    margin-top: 15px;
}

/* 关于我区域 */
.about {
    padding: 80px 0;
    background: white;
}

.about-content {
    display: grid;
    grid-template-columns: 2fr 1fr;
    gap: 60px;
    align-items: start;
}

.about-text {
    font-size: 1.1rem;
    line-height: 1.8;
}

.about-text ul {
    margin-top: 20px;
    padding-left: 20px;
}

.about-text li {
    margin-bottom: 10px;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.skill-item {
    background: var(--gradient-1);
    color: white;
    padding: 15px;
    border-radius: 8px;
    text-align: center;
    font-weight: 500;
    transition: transform var(--animation-duration) var(--animation-easing);
}

.skill-item:hover {
    transform: translateY(-3px);
}

/* 联系方式区域 */
.contact {
    padding: 80px 0;
    background: var(--light-color);
}

.contact-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
}

.contact-item {
    margin-bottom: 20px;
    font-size: 1.1rem;
}

.contact-form {
    background: white;
    padding: 30px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-medium);
}

.contact-form h3 {
    margin-bottom: 20px;
    color: var(--dark-color);
}

.contact-form input,
.contact-form textarea {
    width: 100%;
    padding: 12px;
    margin-bottom: 15px;
    border: 2px solid #e9ecef;
    border-radius: 8px;
    font-family: inherit;
    font-size: 1rem;
    transition: border-color var(--animation-duration) var(--animation-easing);
}

.contact-form input:focus,
.contact-form textarea:focus {
    outline: none;
    border-color: var(--primary-color);
}

.contact-form textarea {
    min-height: 120px;
    resize: vertical;
}

.contact-form button {
    width: 100%;
    padding: 15px;
    background: var(--primary-color);
    color: white;
    border: none;
    border-radius: 8px;
    font-size: 1.1rem;
    cursor: pointer;
    transition: all var(--animation-duration) var(--animation-easing);
}

.contact-form button:hover {
    background: #2980b9;
    transform: translateY(-2px);
}

/* 页脚 */
.footer {
    background: var(--dark-color);
    color: white;
    text-align: center;
    padding: 30px 0;
}

.footer a {
    color: white;
    text-decoration: none;
    transition: color var(--animation-duration) var(--animation-easing);
}

.footer a:hover {
    color: var(--primary-color);
    text-decoration: underline;
}

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

@keyframes pulse {
    0% { transform: scale(1); }
    50% { transform: scale(1.05); }
    100% { transform: scale(1); }
}

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

/* 响应式设计 */
@media (max-width: 768px) {
    .nav-menu {
        display: none;
    }
    
    .nav-toggle {
        display: flex;
    }
    
    .hero-title {
        font-size: 2.5rem;
    }
    
    .demo-section {
        grid-template-columns: 1fr;
    }
    
    .demo-code {
        border-right: none;
        border-bottom: 1px solid #e9ecef;
    }
    
    .about-content,
    .contact-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .skills-grid {
        grid-template-columns: 1fr;
    }
    
    .flex-container {
        flex-direction: column;
    }
    
    .flex-item {
        flex: none;
        width: 100%;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 2rem;
    }
    
    .section-title {
        font-size: 2rem;
    }
    
    .demo-code, .demo-effect {
        padding: 20px;
    }
    
    .grid-container {
        grid-template-columns: 1fr;
    }
}