/* ═══════ 咔咔网站全局样式 ═══════ */
:root {
    --bg-body: #f0f4fa;
    --bg-card: #ffffff;
    --bg-card-hover: #f8fafd;
    --bg-nav: rgba(255, 255, 255, 0.92);
    --bg-alt: #e8eef6;
    --text: #0f172a;
    --text-secondary: #475569;
    --text-muted: #94a3b8;
    --border: #e2e8f0;
    --border-light: #f1f5f9;
    --accent: #2563eb;
    --accent-dark: #1d4ed8;
    --accent-light: #3b82f6;
    --accent-soft: #eff6ff;
    --accent-glow: rgba(37, 99, 235, 0.18);
    --gradient-1: linear-gradient(135deg, #2563eb 0%, #3b82f6 50%, #1d4ed8 100%);
    --gradient-2: linear-gradient(135deg, #0ea5e9 0%, #2563eb 100%);
    --gradient-hero: linear-gradient(170deg, #eff6ff 0%, #e0ecff 30%, #f0f4fa 100%);
    --radius-sm: 8px;
    --radius: 14px;
    --radius-lg: 20px;
    --shadow: 0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.06);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.08);
    --shadow-xl: 0 16px 48px rgba(37, 99, 235, 0.12);
    --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
    --font-mono: 'SF Mono', 'Fira Code', 'Cascadia Code', monospace;
}

* { margin:0; padding:0; box-sizing:border-box; }
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;
    background: var(--bg-body);
    color: var(--text);
    line-height: 1.75;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    position: relative;
    z-index: 1;
}

/* ═══════ 导航栏 ═══════ */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: var(--bg-nav);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border-bottom: 1px solid var(--border);
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
    transition: var(--transition);
}
nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.65rem 0;
}
.logo {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    font-size: 1.45rem;
    font-weight: 800;
    text-decoration: none;
    color: var(--text);
    letter-spacing: -0.02em;
    transition: var(--transition);
}
.logo:hover { opacity: 0.8; }
.logo img {
    height: 34px;
    width: auto;
    border-radius: 6px;
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.2);
}
.logo span {
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.nav-links {
    display: flex;
    gap: 0.25rem;
    list-style: none;
    align-items: center;
}
.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    font-size: 0.92rem;
    padding: 0.5rem 1rem;
    border-radius: 8px;
    transition: var(--transition);
    white-space: nowrap;
}
.nav-links a:hover,
.nav-links a.active {
    color: var(--accent);
    background: var(--accent-soft);
}
.btn-nav {
    background: var(--accent) !important;
    color: #fff !important;
    padding: 0.5rem 1.4rem !important;
    border-radius: 999px !important;
    font-weight: 700 !important;
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.25);
    letter-spacing: 0.02em;
}
.btn-nav:hover {
    background: var(--accent-dark) !important;
    transform: translateY(-1px);
    box-shadow: 0 4px 14px rgba(37, 99, 235, 0.35) !important;
}

/* 移动端菜单 */
.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    z-index: 1010;
}
.menu-toggle span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text);
    border-radius: 2px;
    transition: var(--transition);
}

/* ═══════ 面包屑 ═══════ */
.breadcrumb {
    padding: 1.2rem 0 0.6rem;
    font-size: 0.85rem;
    color: var(--text-muted);
}
.breadcrumb a {
    color: var(--text-secondary);
    text-decoration: none;
}
.breadcrumb a:hover { color: var(--accent); }
.breadcrumb .sep { margin: 0 0.5rem; opacity: 0.5; }
.breadcrumb .current { color: var(--accent); font-weight: 600; }

/* ═══════ 通用区块 ═══════ */
section { padding: 5rem 0; position: relative; z-index: 1; }
.section-header { text-align: center; margin-bottom: 3.5rem; }
.section-badge {
    display: inline-block;
    padding: 0.3rem 1rem;
    border-radius: 999px;
    font-size: 0.82rem;
    font-weight: 600;
    letter-spacing: 0.04em;
    background: var(--accent-soft);
    color: var(--accent);
    margin-bottom: 1rem;
}
.section-title {
    font-size: clamp(1.8rem, 4vw, 2.5rem);
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 0.75rem;
    color: var(--text);
}
.section-title span {
    background: var(--gradient-1);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.section-subtitle {
    color: var(--text-muted);
    font-size: 1.05rem;
    max-width: 600px;
    margin: 0 auto;
}

/* ═══════ 按钮 ═══════ */
.btn {
    display: inline-block;
    padding: 0.8rem 2rem;
    border-radius: 999px;
    font-weight: 700;
    text-decoration: none;
    cursor: pointer;
    transition: var(--transition);
    border: none;
    font-size: 1rem;
    letter-spacing: 0.02em;
}
.btn-primary {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 2px 8px rgba(37, 99, 235, 0.25);
}
.btn-primary:hover {
    background: var(--accent-dark);
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(37, 99, 235, 0.35);
}
.btn-outline {
    border: 2px solid var(--border);
    color: var(--accent);
    background: var(--bg-card);
}
.btn-outline:hover {
    background: var(--accent-soft);
    border-color: var(--accent);
}
.btn-cyan {
    background: var(--gradient-2);
    color: #fff;
    box-shadow: 0 2px 8px rgba(14, 165, 233, 0.25);
}
.btn-cyan:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(14, 165, 233, 0.35);
}

/* ═══════ 卡片 ═══════ */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
}
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem 1.6rem;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow);
}
.card::before {
    content: '';
    position: absolute;
    top: 0; left: 0;
    width: 100%; height: 3px;
    background: var(--gradient-1);
    opacity: 0;
    transition: var(--transition);
}
.card:hover {
    border-color: var(--accent-light);
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}
.card:hover::before { opacity: 1; }
.card-icon { font-size: 2.4rem; margin-bottom: 1rem; display: block; }
.card h3 { font-size: 1.15rem; font-weight: 700; margin-bottom: 0.5rem; color: var(--text); }
.card p { color: var(--text-secondary); font-size: 0.92rem; line-height: 1.7; }

/* ═══════ 底部 ═══════ */
footer {
    border-top: 1px solid var(--border);
    text-align: center;
    padding: 2.5rem 0;
    color: var(--text-muted);
    font-size: 0.88rem;
    position: relative;
    z-index: 1;
    background: var(--bg-card);
}
footer a {
    color: var(--text-secondary);
    text-decoration: none;
    margin: 0 0.5rem;
    transition: var(--transition);
}
footer a:hover { color: var(--accent); }
.footer-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.3rem 1.2rem;
    margin-bottom: 1rem;
}

/* ═══════ CTA Banner ═══════ */
.cta-banner {
    background: var(--gradient-1);
    border-radius: var(--radius-lg);
    padding: 3.5rem 2rem;
    text-align: center;
    margin: 2rem 0;
    box-shadow: var(--shadow-xl);
    position: relative;
    overflow: hidden;
}
.cta-banner::after {
    content: '';
    position: absolute;
    top: -50%; right: -20%;
    width: 400px; height: 400px;
    background: rgba(255,255,255,0.06);
    border-radius: 50%;
    pointer-events: none;
}
.cta-banner h2 { font-size: 2rem; margin-bottom: 0.75rem; font-weight: 800; color: #fff; }
.cta-banner p { opacity: 0.9; margin-bottom: 2rem; font-size: 1.1rem; color: #fff; }
.btn-white {
    display: inline-block;
    background: #fff;
    color: var(--accent);
    padding: 0.85rem 2.5rem;
    border-radius: 999px;
    font-weight: 700;
    text-decoration: none;
    font-size: 1.05rem;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}
.btn-white:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 24px rgba(0,0,0,0.15);
    background: #f5f7ff;
}

/* ═══════ 响应式 ═══════ */
@media (max-width: 768px) {
    .menu-toggle { display: flex; }
    .nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 68px;
        left: 0;
        width: 100%;
        background: rgba(255,255,255,0.98);
        backdrop-filter: blur(16px);
        padding: 1.5rem 1.5rem;
        gap: 0.3rem;
        border-bottom: 1px solid var(--border);
        box-shadow: 0 4px 12px rgba(0,0,0,0.06);
    }
    .nav-links.active { display: flex; }
    .nav-links a { padding: 0.7rem 1rem; font-size: 1rem; }
    section { padding: 3rem 0; }
    .btn { padding: 0.7rem 1.6rem; font-size: 0.95rem; }
}