/* ========================================
   班级图片展示网站 - 主样式表
   响应式设计 | 现代风格 | 动画效果
   ======================================== */

/* === 全局重置与基础样式 === */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #667eea;
    --secondary-color: #764ba2;
    --accent-color: #f093fb;
    --text-dark: #2d3748;
    --text-light: #718096;
    --bg-light: #f7fafc;
    --white: #ffffff;
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.1);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.15);
    --shadow-lg: 0 8px 32px rgba(0, 0, 0, 0.2);
    --transition: all 0.3s ease;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 
                 'Hiragino Sans GB', 'Microsoft YaHei', 'Helvetica Neue', 
                 Helvetica, Arial, sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--bg-light);
    overflow-x: hidden;
}

/* === 导航栏样式 === */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    padding: 1rem 2rem;
    box-shadow: var(--shadow-md);
    z-index: 1000;
    animation: slideDown 0.5s ease;
}

@keyframes slideDown {
    from {
        transform: translateY(-100%);
        opacity: 0;
    }
    to {
        transform: translateY(0);
        opacity: 1;
    }
}

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

.logo {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    text-decoration: none;
    color: var(--white);
    font-size: 1.5rem;
    font-weight: bold;
    transition: var(--transition);
}

.logo:hover {
    transform: scale(1.05);
}

.logo img {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--white);
}

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

.nav-links a {
    color: var(--white);
    text-decoration: none;
    font-weight: 500;
    position: relative;
    padding: 0.5rem 0;
    transition: var(--transition);
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--white);
    transition: width 0.3s ease;
}

.nav-links a:hover::after,
.nav-links a.active::after {
    width: 100%;
}

.nav-links a:hover {
    opacity: 0.9;
}

/* 移动端菜单按钮 */
.menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 4px;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background: var(--white);
    border-radius: 3px;
    transition: var(--transition);
}

/* === 主要内容区域 === */
main {
    margin-top: 80px;
    min-height: calc(100vh - 80px);
}

/* === Hero 区域 === */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: var(--white);
    padding: 4rem 2rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.hero::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -10%;
    width: 500px;
    height: 500px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0) rotate(0deg);
    }
    50% {
        transform: translateY(-20px) rotate(180deg);
    }
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    z-index: 1;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    animation: fadeInUp 0.8s ease;
}

.hero p {
    font-size: 1.25rem;
    opacity: 0.95;
    animation: fadeInUp 0.8s ease 0.2s backwards;
}

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

/* === 图片画廊区域 === */
.gallery-section {
    padding: 4rem 2rem;
    max-width: 1200px;
    margin: 0 auto;
}

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 1rem;
    color: var(--text-dark);
    position: relative;
    display: inline-block;
    left: 50%;
    transform: translateX(-50%);
}

.section-title::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color), var(--accent-color));
    border-radius: 2px;
}

.section-subtitle {
    text-align: center;
    color: var(--text-light);
    font-size: 1.1rem;
    margin-bottom: 3rem;
    margin-top: 1.5rem;
}

/* 画廊网格布局 */
.gallery-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

/* 图片卡片 */
.gallery-item {
    position: relative;
    border-radius: 12px;
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    background: var(--white);
    cursor: pointer;
}

.gallery-item:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
}

.gallery-item img {
    width: 100%;
    height: 250px;
    object-fit: cover;
    display: block;
    transition: transform 0.5s ease;
}

.gallery-item:hover img {
    transform: scale(1.1);
}

/* 图片遮罩层 */
.gallery-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(to top, rgba(102, 126, 234, 0.9), transparent);
    display: flex;
    flex-direction: column;
    justify-content: flex-end;
    padding: 1.5rem;
    opacity: 0;
    transition: opacity 0.3s ease;
}

.gallery-item:hover .gallery-overlay {
    opacity: 1;
}

.gallery-overlay h3 {
    color: var(--white);
    font-size: 1.25rem;
    margin-bottom: 0.5rem;
    transform: translateY(20px);
    transition: transform 0.3s ease;
}

.gallery-overlay p {
    color: rgba(255, 255, 255, 0.9);
    font-size: 0.9rem;
    transform: translateY(20px);
    transition: transform 0.3s ease 0.1s;
}

.gallery-item:hover .gallery-overlay h3,
.gallery-item:hover .gallery-overlay p {
    transform: translateY(0);
}

/* === 关于页面样式 === */
.about-hero {
    background: linear-gradient(135deg, var(--secondary-color), var(--accent-color));
    color: var(--white);
    padding: 4rem 2rem;
    text-align: center;
}

.about-content {
    max-width: 1000px;
    margin: 0 auto;
    padding: 4rem 2rem;
}

.about-section {
    margin-bottom: 3rem;
    background: var(--white);
    padding: 2.5rem;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
}

.about-section:hover {
    box-shadow: var(--shadow-md);
    transform: translateX(5px);
}

.about-section h2 {
    color: var(--primary-color);
    font-size: 2rem;
    margin-bottom: 1.5rem;
    display: flex;
    align-items: center;
    gap: 0.75rem;
}

.about-section h2::before {
    content: '▎';
    color: var(--accent-color);
}

.about-section p {
    color: var(--text-light);
    line-height: 1.8;
    margin-bottom: 1rem;
}

.info-list {
    list-style: none;
    margin-top: 1.5rem;
}

.info-list li {
    padding: 0.75rem 0;
    border-bottom: 1px solid #e2e8f0;
    display: flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-dark);
}

.info-list li:last-child {
    border-bottom: none;
}

.info-list li strong {
    color: var(--primary-color);
    min-width: 100px;
}

/* === 页脚样式 === */
.footer {
    background: linear-gradient(135deg, var(--text-dark), #1a202c);
    color: var(--white);
    padding: 2rem;
    text-align: center;
    margin-top: 4rem;
}

.footer-content {
    max-width: 1200px;
    margin: 0 auto;
}

.footer p {
    opacity: 0.9;
    margin: 0.5rem 0;
}

.footer-links {
    display: flex;
    justify-content: center;
    gap: 2rem;
    margin-top: 1rem;
    list-style: none;
}

.footer-links a {
    color: var(--white);
    text-decoration: none;
    opacity: 0.8;
    transition: var(--transition);
}

.footer-links a:hover {
    opacity: 1;
    text-decoration: underline;
}

/* === 响应式设计 === */

/* 平板设备 (768px - 1024px) */
@media screen and (max-width: 1024px) {
    .hero h1 {
        font-size: 2.5rem;
    }

    .gallery-grid {
        grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
        gap: 1.5rem;
    }

    .section-title {
        font-size: 2rem;
    }
}

/* 手机设备 (< 768px) */
@media screen and (max-width: 768px) {
    .navbar {
        padding: 1rem;
    }

    .menu-toggle {
        display: flex;
    }

    .nav-links {
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
        flex-direction: column;
        align-items: center;
        padding: 2rem;
        gap: 1.5rem;
        transform: translateY(-150%);
        transition: transform 0.3s ease;
        box-shadow: var(--shadow-md);
    }

    .nav-links.active {
        transform: translateY(0);
    }

    .hero {
        padding: 3rem 1.5rem;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .hero p {
        font-size: 1rem;
    }

    .gallery-section {
        padding: 3rem 1rem;
    }

    .gallery-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .section-title {
        font-size: 1.75rem;
    }

    .about-content {
        padding: 2rem 1rem;
    }

    .about-section {
        padding: 1.5rem;
    }

    .about-section h2 {
        font-size: 1.5rem;
    }

    .footer-links {
        flex-direction: column;
        gap: 1rem;
    }
}

/* 小屏手机 (< 480px) */
@media screen and (max-width: 480px) {
    .hero h1 {
        font-size: 1.75rem;
    }

    .section-title {
        font-size: 1.5rem;
    }

    .gallery-item img {
        height: 200px;
    }
}

/* === 辅助类 === */
.text-center {
    text-align: center;
}

.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mt-4 { margin-top: 2rem; }

.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.mb-4 { margin-bottom: 2rem; }

/* === 加载动画 === */
.loading {
    display: inline-block;
    width: 40px;
    height: 40px;
    border: 4px solid rgba(102, 126, 234, 0.2);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* === 打印样式优化 === */
@media print {
    .navbar,
    .footer,
    .gallery-overlay {
        display: none;
    }

    body {
        background: white;
        color: black;
    }

    .gallery-item {
        break-inside: avoid;
        box-shadow: none;
        border: 1px solid #ddd;
    }
}