/* ===== Reset & Base ===== */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    --primary: #4F46E5;
    --primary-dark: #4338CA;
    --bg: #F9FAFB;
    --surface: #FFFFFF;
    --text: #1F2937;
    --text-secondary: #6B7280;
    --border: #E5E7EB;
    --radius: 12px;
    --shadow: 0 1px 3px rgba(0,0,0,.08), 0 1px 2px rgba(0,0,0,.06);
    --shadow-lg: 0 10px 25px rgba(0,0,0,.08);
}

html { scroll-behavior: smooth; }
body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--primary); text-decoration: none; transition: color .2s; }
a:hover { color: var(--primary-dark); }
img { max-width: 100%; }

.container { max-width: 1140px; margin: 0 auto; padding: 0 20px; }

/* ===== Header ===== */
.header {
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 100;
}
.nav {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 64px;
}
.logo {
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--text);
}
.logo:hover { color: var(--primary); }
.nav-links {
    display: flex;
    list-style: none;
    gap: 28px;
}
.nav-links a {
    color: var(--text-secondary);
    font-size: .95rem;
    font-weight: 500;
    transition: color .2s;
}
.nav-links a:hover { color: var(--primary); }
.mobile-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text);
}

/* ===== Hero ===== */
.hero {
    padding: 80px 0 60px;
    text-align: center;
    background: linear-gradient(135deg, #EEF2FF 0%, #F9FAFB 100%);
}
.hero h1 {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 16px;
    color: var(--text);
}
.hero-sub {
    font-size: 1.15rem;
    color: var(--text-secondary);
    max-width: 520px;
    margin: 0 auto 32px;
}
.btn {
    display: inline-block;
    padding: 12px 32px;
    border-radius: 8px;
    font-weight: 600;
    font-size: 1rem;
    transition: all .2s;
}
.btn-primary {
    background: var(--primary);
    color: #fff;
}
.btn-primary:hover {
    background: var(--primary-dark);
    color: #fff;
    transform: translateY(-1px);
    box-shadow: var(--shadow-lg);
}

/* ===== Section Title ===== */
.section-title {
    text-align: center;
    font-size: 1.8rem;
    font-weight: 700;
    margin-bottom: 48px;
}

/* ===== Tools Grid ===== */
.tools-section { padding: 72px 0; }
.tools-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}
.tool-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 28px;
    transition: all .25s;
}
.tool-card:hover {
    box-shadow: var(--shadow-lg);
    transform: translateY(-3px);
    border-color: var(--primary);
}
.tool-icon { font-size: 2rem; margin-bottom: 12px; }
.tool-card h3 { font-size: 1.15rem; margin-bottom: 8px; }
.tool-card p { font-size: .9rem; color: var(--text-secondary); margin-bottom: 16px; }
.tool-link { font-size: .9rem; font-weight: 600; }

/* ===== Features ===== */
.features-section {
    padding: 72px 0;
    background: var(--surface);
}
.features-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 32px;
}
.feature-item { padding: 8px; }
.feature-item h3 { font-size: 1.1rem; margin-bottom: 8px; }
.feature-item p { color: var(--text-secondary); font-size: .95rem; }

/* ===== Stats ===== */
.stats-section {
    padding: 56px 0;
    background: linear-gradient(135deg, #4F46E5, #7C3AED);
    color: #fff;
}
.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
    text-align: center;
}
.stat-num { display: block; font-size: 2rem; font-weight: 800; }
.stat-label { font-size: .9rem; opacity: .85; }

/* ===== Footer ===== */
.footer {
    background: #111827;
    color: #D1D5DB;
    padding: 48px 0 24px;
}
.footer-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 32px;
    margin-bottom: 32px;
}
.footer-col h4 {
    color: #fff;
    font-size: 1rem;
    margin-bottom: 16px;
}
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 8px; font-size: .9rem; }
.footer-col a { color: #9CA3AF; }
.footer-col a:hover { color: #fff; }
.footer-bottom {
    border-top: 1px solid #374151;
    padding-top: 20px;
    text-align: center;
    font-size: .85rem;
    color: #6B7280;
}

/* ===== Legal Pages (about / privacy / terms) ===== */
.legal-page {
    max-width: 760px;
    margin: 0 auto;
    padding: 56px 20px 72px;
}
.legal-page h1 {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 8px;
}
.legal-page .update-date {
    color: var(--text-secondary);
    font-size: .9rem;
    margin-bottom: 36px;
}
.legal-page h2 {
    font-size: 1.3rem;
    margin: 32px 0 12px;
    font-weight: 600;
}
.legal-page p, .legal-page li {
    font-size: .95rem;
    color: #374151;
    margin-bottom: 12px;
    line-height: 1.75;
}
.legal-page ul { padding-left: 20px; }

/* ===== Responsive ===== */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .mobile-toggle { display: block; }
    .hero h1 { font-size: 1.8rem; }
    .hero { padding: 56px 0 40px; }
    .tools-grid { grid-template-columns: 1fr; }
    .features-grid { grid-template-columns: 1fr; }
    .stats-grid { grid-template-columns: repeat(2, 1fr); gap: 16px; }
    .footer-grid { grid-template-columns: 1fr; }
}