/* ===== CSS变量与重置 ===== */
:root {
    --primary: #6366f1;
    --primary-dark: #4f46e5;
    --secondary: #8b5cf6;
    --accent: #06b6d4;
    --bg-dark: #0f172a;
    --bg-card: #1e293b;
    --bg-light: #f8fafc;
    --text-primary: #e2e8f0;
    --text-secondary: #94a3b8;
    --text-dark: #1e293b;
    --border: #334155;
    --shadow: 0 4px 20px rgba(0,0,0,0.3);
    --shadow-hover: 0 8px 30px rgba(99,102,241,0.2);
    --radius: 16px;
    --radius-sm: 8px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background: var(--bg-dark);
    color: var(--text-primary);
    line-height: 1.6;
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(15, 23, 42, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid transparent;
    transition: var(--transition);
}

.navbar.scrolled {
    border-bottom: 1px solid var(--border);
    box-shadow: 0 2px 20px rgba(0,0,0,0.3);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
    height: 72px;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.nav-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo-icon {
    width: 40px;
    height: 40px;
}

.logo-text {
    font-size: 22px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.nav-menu {
    display: flex;
    gap: 32px;
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 15px;
    font-weight: 500;
    transition: var(--transition);
    position: relative;
    padding: 4px 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -2px;
    left: 0;
    width: 0;
    height: 2px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    transition: var(--transition);
    border-radius: 2px;
}

.nav-link:hover,
.nav-link.active {
    color: var(--text-primary);
}

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

.nav-right {
    display: flex;
    align-items: center;
    gap: 16px;
}

.btn-admin {
    padding: 8px 20px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border-radius: 50px;
    text-decoration: none;
    font-size: 14px;
    font-weight: 500;
    transition: var(--transition);
    display: flex;
    align-items: center;
    gap: 8px;
}

.btn-admin:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 15px rgba(99,102,241,0.4);
}

/* 汉堡菜单 */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(5px, -5px);
}

/* ===== Hero区域 ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    padding: 120px 20px 80px;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 
        radial-gradient(ellipse at 20% 50%, rgba(99,102,241,0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 50%, rgba(139,92,246,0.15) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 100%, rgba(6,182,212,0.1) 0%, transparent 50%);
    z-index: 0;
}

.hero-content {
    text-align: center;
    position: relative;
    z-index: 1;
    max-width: 800px;
}

.hero-logo {
    width: 280px;
    margin-bottom: 32px;
    animation: fadeInUp 0.8s ease;
}

.hero-slogan {
    font-size: 48px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--text-primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 20px;
    animation: fadeInUp 0.8s ease 0.2s both;
}

.hero-desc {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 40px;
    line-height: 1.8;
    animation: fadeInUp 0.8s ease 0.4s both;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    justify-content: center;
    flex-wrap: wrap;
    animation: fadeInUp 0.8s ease 0.6s both;
}

.btn-primary,
.btn-secondary {
    padding: 16px 36px;
    border-radius: 50px;
    font-size: 16px;
    font-weight: 600;
    text-decoration: none;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    gap: 10px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    box-shadow: 0 4px 20px rgba(99,102,241,0.3);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 30px rgba(99,102,241,0.5);
}

.btn-secondary {
    background: rgba(255,255,255,0.1);
    color: var(--text-primary);
    border: 1px solid var(--border);
}

.btn-secondary:hover {
    background: rgba(255,255,255,0.15);
    transform: translateY(-3px);
}

.hero-stats {
    display: flex;
    justify-content: center;
    gap: 60px;
    margin-top: 60px;
    animation: fadeInUp 0.8s ease 0.8s both;
}

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

.stat-number {
    display: block;
    font-size: 40px;
    font-weight: 700;
    background: linear-gradient(135deg, var(--primary), var(--accent));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 4px;
}

/* ===== 通用区块 ===== */
section {
    padding: 100px 0;
}

.section-header {
    text-align: center;
    margin-bottom: 60px;
}

.section-header h2 {
    font-size: 36px;
    font-weight: 700;
    margin-bottom: 12px;
    background: linear-gradient(135deg, var(--text-primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.section-header p {
    font-size: 16px;
    color: var(--text-secondary);
}

/* ===== 核心能力 ===== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 24px;
}

.feature-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 36px 28px;
    transition: var(--transition);
    border: 1px solid transparent;
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, var(--primary), var(--secondary));
    transform: scaleX(0);
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    border-color: var(--border);
    box-shadow: var(--shadow-hover);
}

.feature-card:hover::before {
    transform: scaleX(1);
}

.feature-icon {
    width: 60px;
    height: 60px;
    background: linear-gradient(135deg, rgba(99,102,241,0.2), rgba(139,92,246,0.2));
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
}

.feature-icon i {
    font-size: 28px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.feature-card h3 {
    font-size: 20px;
    font-weight: 600;
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.7;
}

/* ===== AI工具 ===== */
.tools {
    background: linear-gradient(180deg, var(--bg-dark) 0%, rgba(30, 41, 59, 0.5) 100%);
}

.tool-filters {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
    margin-top: 24px;
}

.filter-btn {
    padding: 10px 24px;
    border-radius: 50px;
    border: 1px solid var(--border);
    background: transparent;
    color: var(--text-secondary);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.filter-btn:hover,
.filter-btn.active {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border-color: transparent;
}

.tools-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 24px;
}

.tool-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 28px;
    transition: var(--transition);
    border: 1px solid transparent;
    position: relative;
}

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

.tool-card .tool-icon {
    width: 52px;
    height: 52px;
    background: linear-gradient(135deg, rgba(99,102,241,0.2), rgba(139,92,246,0.2));
    border-radius: 14px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 16px;
}

.tool-card .tool-icon i {
    font-size: 24px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.tool-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
}

.tool-card p {
    color: var(--text-secondary);
    font-size: 13px;
    line-height: 1.6;
    margin-bottom: 16px;
}

.tool-card .tool-tag {
    display: inline-block;
    padding: 4px 12px;
    border-radius: 50px;
    font-size: 12px;
    font-weight: 500;
    background: rgba(99,102,241,0.15);
    color: var(--primary);
    margin-bottom: 16px;
}

.tool-card .tool-link {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    color: var(--primary);
    font-size: 14px;
    font-weight: 500;
    text-decoration: none;
    transition: var(--transition);
}

.tool-card .tool-link:hover {
    gap: 12px;
    color: var(--secondary);
}

/* ===== 关于我们 ===== */
.about-content {
    display: flex;
    flex-direction: column;
    gap: 48px;
}

.about-story {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 40px;
    border: 1px solid var(--border);
}

.about-story h3 {
    font-size: 24px;
    font-weight: 600;
    margin-bottom: 20px;
}

.about-story p {
    color: var(--text-secondary);
    font-size: 15px;
    line-height: 1.8;
    margin-bottom: 12px;
}

.about-mission {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: 24px;
}

.mission-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 32px;
    text-align: center;
    border: 1px solid var(--border);
    transition: var(--transition);
}

.mission-card:hover {
    transform: translateY(-6px);
    border-color: var(--primary);
    box-shadow: var(--shadow-hover);
}

.mission-card i {
    font-size: 36px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 16px;
}

.mission-card h4 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 8px;
}

.mission-card p {
    color: var(--text-secondary);
    font-size: 14px;
}

/* ===== 联系我们 ===== */
.contact-content {
    display: grid;
    grid-template-columns: 1fr 1.5fr;
    gap: 40px;
}

.contact-info {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.info-item {
    display: flex;
    align-items: flex-start;
    gap: 16px;
    background: var(--bg-card);
    border-radius: var(--radius-sm);
    padding: 20px;
    border: 1px solid var(--border);
    transition: var(--transition);
}

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

.info-item i {
    font-size: 24px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-top: 2px;
}

.info-item h4 {
    font-size: 15px;
    font-weight: 600;
    margin-bottom: 4px;
}

.info-item p {
    color: var(--text-secondary);
    font-size: 13px;
}

.contact-form {
    background: var(--bg-card);
    border-radius: var(--radius);
    padding: 36px;
    border: 1px solid var(--border);
}

.form-group {
    margin-bottom: 20px;
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 14px 18px;
    background: rgba(255,255,255,0.05);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-primary);
    font-size: 14px;
    font-family: inherit;
    transition: var(--transition);
    outline: none;
}

.form-group input:focus,
.form-group textarea:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(99,102,241,0.15);
}

.form-group input::placeholder,
.form-group textarea::placeholder {
    color: var(--text-secondary);
}

.contact-form .btn-primary {
    width: 100%;
    justify-content: center;
    cursor: pointer;
    border: none;
    font-family: inherit;
}

/* ===== 页脚 ===== */
.footer {
    background: linear-gradient(180deg, var(--bg-dark) 0%, #0a0f1a 100%);
    border-top: 1px solid var(--border);
    padding: 80px 0 0;
}

.footer-content {
    display: grid;
    grid-template-columns: 1.5fr 2fr;
    gap: 60px;
    padding-bottom: 40px;
}

.footer-logo {
    width: 180px;
    margin-bottom: 20px;
}

.footer-brand p {
    color: var(--text-secondary);
    font-size: 14px;
    line-height: 1.7;
    margin-bottom: 24px;
}

.social-links {
    display: flex;
    gap: 12px;
}

.social-links a {
    width: 40px;
    height: 40px;
    background: rgba(255,255,255,0.08);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--text-secondary);
    font-size: 18px;
    transition: var(--transition);
    text-decoration: none;
}

.social-links a:hover {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    transform: translateY(-3px);
}

.footer-links {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
}

.link-group h4 {
    font-size: 16px;
    font-weight: 600;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.link-group a {
    display: block;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 14px;
    padding: 6px 0;
    transition: var(--transition);
}

.link-group a:hover {
    color: var(--primary);
    padding-left: 4px;
}

.footer-bottom {
    border-top: 1px solid var(--border);
    padding: 24px 0;
    text-align: center;
}

.footer-bottom p {
    color: var(--text-secondary);
    font-size: 13px;
}

/* ===== 回到顶部 ===== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 20px;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(99,102,241,0.3);
    transition: var(--transition);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 25px rgba(99,102,241,0.5);
}

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

/* ===== 响应式 ===== */
@media (max-width: 1024px) {
    .hero-slogan {
        font-size: 40px;
    }
    .hero-stats {
        gap: 40px;
    }
    .stat-number {
        font-size: 32px;
    }
}

@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 72px;
        left: 0;
        right: 0;
        background: rgba(15, 23, 42, 0.98);
        backdrop-filter: blur(20px);
        flex-direction: column;
        padding: 24px;
        gap: 16px;
        transform: translateY(-100%);
        opacity: 0;
        transition: var(--transition);
        border-bottom: 1px solid var(--border);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
    }

    .nav-link {
        font-size: 16px;
        padding: 12px 0;
    }

    .hamburger {
        display: flex;
    }

    .nav-right .btn-admin {
        display: none;
    }

    .hero-slogan {
        font-size: 32px;
    }

    .hero-desc {
        font-size: 16px;
    }

    .hero-stats {
        gap: 24px;
        flex-wrap: wrap;
    }

    .stat-number {
        font-size: 28px;
    }

    .hero-logo {
        width: 200px;
    }

    .section-header h2 {
        font-size: 28px;
    }

    .contact-content {
        grid-template-columns: 1fr;
    }

    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .footer-links {
        grid-template-columns: repeat(2, 1fr);
    }

    section {
        padding: 60px 0;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
        font-size: 16px;
    }
}

@media (max-width: 480px) {
    .hero-slogan {
        font-size: 26px;
    }

    .hero-logo {
        width: 160px;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: center;
    }

    .btn-primary,
    .btn-secondary {
        width: 100%;
        justify-content: center;
    }

    .hero-stats {
        gap: 16px;
    }

    .stat-number {
        font-size: 24px;
    }

    .tools-grid,
    .features-grid {
        grid-template-columns: 1fr;
    }

    .footer-links {
        grid-template-columns: 1fr;
    }
}