/* ===========================
   iClassdee 备案官网样式
   定位：照片管理与分享平台
   =========================== */

/* --- 设计系统 --- */
:root {
    --color-primary: #3b82f6;
    --color-primary-dark: #2563eb;
    --color-secondary: #06b6d4;
    --color-accent: #8b5cf6;
    --color-success: #10b981;

    --color-text: #1e293b;
    --color-text-secondary: #64748b;
    --color-text-light: #94a3b8;

    --color-bg: #ffffff;
    --color-bg-soft: #f8fafc;
    --color-bg-card: #ffffff;

    --color-border: #e2e8f0;

    --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
        "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica,
        Arial, sans-serif;

    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 16px rgba(0, 0, 0, 0.08);
    --shadow-lg: 0 12px 40px rgba(0, 0, 0, 0.12);
    --shadow-xl: 0 20px 60px rgba(0, 0, 0, 0.15);

    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 20px;
    --radius-xl: 24px;

    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* --- 重置 & 基础 --- */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-sans);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.7;
    overflow-x: hidden;
}

.container {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 24px;
}

/* --- 导航栏 --- */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 100;
    padding: 20px 0;
    transition: all var(--transition);
}

.navbar.scrolled {
    padding: 12px 0;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-sm);
}

.nav-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    text-decoration: none;
    color: var(--color-text);
}

.logo-icon {
    width: 36px;
    height: 36px;
}

.logo-text {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.02em;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-links a {
    text-decoration: none;
    color: var(--color-text-secondary);
    font-size: 15px;
    font-weight: 500;
    transition: color var(--transition);
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--color-primary);
    border-radius: 1px;
    transition: width var(--transition);
}

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

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

/* --- Hero --- */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 100px 0 80px;
    overflow: hidden;
}

.hero-bg-shapes {
    position: absolute;
    inset: 0;
    pointer-events: none;
    overflow: hidden;
}

.shape {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.15;
}

.shape-1 {
    width: 600px;
    height: 600px;
    background: var(--color-primary);
    top: -200px;
    right: -100px;
    animation: float 20s ease-in-out infinite;
}

.shape-2 {
    width: 400px;
    height: 400px;
    background: var(--color-secondary);
    bottom: -100px;
    left: -100px;
    animation: float 25s ease-in-out infinite reverse;
}

.shape-3 {
    width: 300px;
    height: 300px;
    background: var(--color-accent);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation: float 18s ease-in-out infinite;
}

@keyframes float {
    0%,
    100% {
        transform: translate(0, 0) scale(1);
    }
    33% {
        transform: translate(30px, -30px) scale(1.05);
    }
    66% {
        transform: translate(-20px, 20px) scale(0.95);
    }
}

.hero-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
    position: relative;
    z-index: 1;
}

.hero-title {
    font-size: clamp(32px, 5vw, 52px);
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: -0.03em;
    margin-bottom: 20px;
}

.gradient-text {
    background: linear-gradient(135deg, var(--color-primary), var(--color-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: 17px;
    line-height: 1.8;
    color: var(--color-text-secondary);
    max-width: 420px;
}

/* 照片堆叠效果 */
.photo-stack {
    position: relative;
    width: 100%;
    max-width: 400px;
    height: 320px;
    margin: 0 auto;
}

.photo-card {
    position: absolute;
    width: 260px;
    background: var(--color-bg-card);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    transition: transform 0.5s cubic-bezier(0.4, 0, 0.2, 1);
}

.photo-card svg {
    display: block;
    width: 100%;
}

.card-1 {
    top: 40px;
    left: 0;
    transform: rotate(-6deg);
    z-index: 1;
}

.card-2 {
    top: 10px;
    left: 80px;
    transform: rotate(3deg);
    z-index: 2;
}

.card-3 {
    top: 60px;
    left: 120px;
    transform: rotate(-2deg);
    z-index: 3;
}

.photo-stack:hover .card-1 {
    transform: rotate(-10deg) translateX(-20px);
}

.photo-stack:hover .card-2 {
    transform: rotate(0deg) translateY(-10px);
}

.photo-stack:hover .card-3 {
    transform: rotate(4deg) translateX(20px);
}

/* --- 功能特色 --- */
.features {
    padding: 100px 0;
    background: var(--color-bg-soft);
}

.section-title {
    font-size: clamp(24px, 3.5vw, 36px);
    font-weight: 700;
    text-align: center;
    letter-spacing: -0.02em;
    margin-bottom: 12px;
}

.section-subtitle {
    text-align: center;
    color: var(--color-text-secondary);
    font-size: 16px;
    margin-bottom: 60px;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.feature-card {
    background: var(--color-bg-card);
    border-radius: var(--radius-lg);
    padding: 36px 28px;
    text-align: center;
    border: 1px solid var(--color-border);
    transition: all var(--transition);
}

.feature-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: transparent;
}

.feature-icon {
    width: 64px;
    height: 64px;
    margin: 0 auto 20px;
}

.feature-icon svg {
    width: 100%;
    height: 100%;
}

.feature-title {
    font-size: 19px;
    font-weight: 700;
    margin-bottom: 10px;
    letter-spacing: -0.01em;
}

.feature-desc {
    font-size: 14.5px;
    color: var(--color-text-secondary);
    line-height: 1.7;
}

/* --- 关于 --- */
.about {
    padding: 100px 0;
}

.about-content {
    max-width: 640px;
    margin: 0 auto;
    text-align: center;
}

.about-content .section-title {
    margin-bottom: 28px;
}

.about-text {
    font-size: 16px;
    color: var(--color-text-secondary);
    line-height: 1.9;
    margin-bottom: 16px;
}

.about-text:last-child {
    margin-bottom: 0;
}

/* --- 页脚 --- */
.footer {
    background: var(--color-bg-soft);
    border-top: 1px solid var(--color-border);
    padding: 32px 0;
}

.footer-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
}

.copyright {
    font-size: 13px;
    color: var(--color-text-light);
}

.icp {
    font-size: 13px;
}

.icp a {
    color: var(--color-text-light);
    text-decoration: none;
    transition: color var(--transition);
}

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

/* --- 动画 --- */
.animate-in {
    opacity: 0;
    transform: translateY(24px);
    transition: opacity 0.6s cubic-bezier(0.4, 0, 0.2, 1),
        transform 0.6s cubic-bezier(0.4, 0, 0.2, 1);
}

.animate-in.visible {
    opacity: 1;
    transform: translateY(0);
}

.delay-1 {
    transition-delay: 0.15s;
}

.delay-2 {
    transition-delay: 0.3s;
}

/* --- 响应式 --- */
@media (max-width: 768px) {
    .hero-content {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 40px;
    }

    .hero-subtitle {
        max-width: 100%;
        margin: 0 auto;
    }

    .hero {
        min-height: auto;
        padding: 120px 0 60px;
    }

    .photo-stack {
        max-width: 320px;
        height: 260px;
    }

    .photo-card {
        width: 200px;
    }

    .card-1 {
        left: 10px;
    }

    .card-2 {
        left: 60px;
    }

    .card-3 {
        left: 90px;
    }

    .features-grid {
        grid-template-columns: 1fr;
        max-width: 400px;
        margin: 0 auto;
    }

    .features {
        padding: 60px 0;
    }

    .about {
        padding: 60px 0;
    }

    .nav-links {
        gap: 20px;
    }

    .nav-links a {
        font-size: 14px;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 16px;
    }

    .hero {
        padding: 100px 0 40px;
    }

    .photo-stack {
        max-width: 280px;
        height: 220px;
    }

    .photo-card {
        width: 170px;
    }

    .card-1 {
        top: 30px;
        left: 5px;
    }

    .card-2 {
        top: 5px;
        left: 50px;
    }

    .card-3 {
        top: 50px;
        left: 80px;
    }

    .section-subtitle {
        margin-bottom: 36px;
    }
}