:root {
    --blue: #dff3ff;
    --blue-deep: #367fa8;
    --orange: #ffb56b;
    --orange-soft: #ffe0bd;
    --yellow: #fff3c8;
    --cream: #fffaf0;
    --white: #ffffff;
    --ink: #23313d;
    --muted: #657583;
    --line: #e5eef4;
    --shadow: 0 18px 45px rgba(54, 127, 168, 0.14);
    --radius: 28px;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", Arial, sans-serif;
    color: var(--ink);
    background: linear-gradient(180deg, #f8fcff 0%, #fffaf0 48%, #ffffff 100%);
    line-height: 1.75;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; height: auto; display: block; }
.container { width: min(1120px, calc(100% - 36px)); margin: 0 auto; }
.skip-link { position: absolute; left: -999px; top: 10px; background: var(--ink); color: #fff; padding: 8px 12px; border-radius: 10px; z-index: 99; }
.skip-link:focus { left: 12px; }
.site-header { position: sticky; top: 0; z-index: 50; background: rgba(255, 255, 255, 0.9); backdrop-filter: blur(14px); border-bottom: 1px solid rgba(229, 238, 244, 0.9); }
.header-inner { min-height: 76px; display: flex; align-items: center; justify-content: space-between; gap: 20px; }
.brand { display: inline-flex; align-items: center; gap: 12px; }
.brand-mark { width: 46px; height: 46px; border-radius: 18px; display: inline-grid; place-items: center; color: #fff; font-weight: 800; font-size: 24px; background: linear-gradient(135deg, var(--orange), #79c6ee); box-shadow: 0 10px 24px rgba(255, 181, 107, 0.35); }
.brand strong { display: block; font-size: 19px; letter-spacing: 0.03em; }
.brand small { display: block; color: var(--muted); font-size: 12px; margin-top: -3px; }
.site-nav { display: flex; align-items: center; gap: 8px; }
.site-nav a { padding: 9px 13px; border-radius: 999px; color: #415260; font-size: 15px; }
.site-nav a:hover, .site-nav a.active { background: var(--blue); color: #195678; }
.nav-toggle { display: none; border: 0; background: var(--blue); border-radius: 14px; width: 44px; height: 44px; font-size: 22px; }
.hero { padding: 82px 0 54px; }
.hero-grid, .page-hero-grid, .split { display: grid; grid-template-columns: 1.04fr 0.96fr; gap: 54px; align-items: center; }
.hero-copy h1, .page-hero h1 { margin: 12px 0 20px; font-size: clamp(36px, 6vw, 64px); line-height: 1.08; letter-spacing: -0.05em; }
.page-hero h1 { font-size: clamp(32px, 5vw, 52px); }
.hero-copy p, .page-hero p, .section-head p { color: var(--muted); font-size: 18px; margin: 0; }
.eyebrow { display: inline-flex; align-items: center; gap: 8px; color: #2b78a0; background: rgba(223, 243, 255, 0.75); border: 1px solid #caebfb; padding: 5px 12px; border-radius: 999px; font-weight: 700; font-size: 14px; }
.hero-actions { display: flex; gap: 14px; margin: 30px 0 24px; flex-wrap: wrap; }
.btn { display: inline-flex; align-items: center; justify-content: center; min-height: 46px; padding: 10px 20px; border-radius: 999px; font-weight: 800; border: 1px solid transparent; cursor: pointer; }
.btn.primary { background: linear-gradient(135deg, var(--orange), #ffcf82); color: #5f330a; box-shadow: 0 13px 28px rgba(255, 181, 107, 0.28); }
.btn.soft { background: var(--white); color: #246486; border-color: #ccebf9; box-shadow: 0 10px 24px rgba(54, 127, 168, 0.08); }
.hero-points, .pill-list { list-style: none; padding: 0; display: flex; flex-wrap: wrap; gap: 10px; margin: 0; }
.hero-points li, .pill-list li, .tag { padding: 6px 12px; border-radius: 999px; background: #fff; border: 1px solid var(--line); color: #52707f; font-weight: 700; font-size: 14px; }
.card-glow { border-radius: 42px; padding: 16px; background: radial-gradient(circle at 20% 20%, #fff3c8, transparent 38%), linear-gradient(135deg, #eff9ff, #fffaf0); box-shadow: var(--shadow); }
.section { padding: 70px 0; }
.section-head { max-width: 760px; margin: 0 auto 34px; text-align: center; }
.section-head.left { margin-left: 0; text-align: left; }
.section-head h2, .split h2, .topic-card h2, .contact-panel h2, .contact-form h2 { font-size: clamp(28px, 4vw, 42px); line-height: 1.18; margin: 14px 0 14px; letter-spacing: -0.03em; }
.age-grid, .content-grid, .safe-grid, .quote-grid, .values-grid, .parent-steps, .video-grid, .contact-grid { display: grid; gap: 22px; }
.age-grid { grid-template-columns: repeat(4, 1fr); }
.content-grid.three, .safe-grid, .values-grid, .parent-steps, .video-grid { grid-template-columns: repeat(3, 1fr); }
.age-card, .feature-card, .media-card, .safe-grid article, .values-grid article, .parent-steps article, .video-card, .contact-form, .contact-panel, .info-panel, .topic-card, blockquote, .age-guide-list article { background: rgba(255,255,255,0.92); border: 1px solid var(--line); border-radius: var(--radius); padding: 26px; box-shadow: 0 12px 30px rgba(54, 127, 168, 0.08); }
.age-badge { display: inline-flex; padding: 6px 13px; border-radius: 999px; background: var(--yellow); color: #805412; font-weight: 800; }
.age-card h3, .feature-card h3, .media-card h3, .safe-grid h3, .video-card h2, .feature-card h2, .age-guide-list h2, .parent-steps h2 { margin: 16px 0 8px; line-height: 1.28; }
.age-card p, .feature-card p, .media-card p, .safe-grid p, .values-grid p, .parent-steps p, .video-card p, .age-guide-list p, .split p, .contact-panel p, .form-note { color: var(--muted); margin: 0; }
.warm-bg { background: linear-gradient(135deg, rgba(255, 243, 200, 0.66), rgba(223, 243, 255, 0.56)); }
.guide-band { background: linear-gradient(135deg, #ffffff, #f2faff); }
.rounded-img { border-radius: 34px; box-shadow: var(--shadow); background: #fff; }
.reverse { grid-template-columns: 0.96fr 1.04fr; }
.mini-list { display: grid; gap: 12px; margin-top: 24px; }
.mini-list div { background: #fff; border: 1px solid var(--line); border-radius: 20px; padding: 14px 16px; display: flex; justify-content: space-between; gap: 16px; }
.mini-list span { color: var(--muted); }
.text-link { display: inline-flex; margin-top: 24px; color: #1f6d94; font-weight: 800; }
.topic-card { display: flex; justify-content: space-between; align-items: center; gap: 24px; background: linear-gradient(135deg, #fff, #e9f8ff); }
.topic-card p { color: var(--muted); max-width: 720px; }
.safe-grid article, .feature-card { overflow: hidden; }
.safe-grid img, .feature-card img { margin: -4px 0 16px; border-radius: 24px; background: #f8fcff; }
blockquote { margin: 0; color: #415260; font-size: 17px; }
.faq-list { display: grid; gap: 14px; max-width: 900px; margin: 0 auto; }
details { background: #fff; border: 1px solid var(--line); border-radius: 22px; padding: 18px 22px; box-shadow: 0 8px 22px rgba(54, 127, 168, 0.06); }
summary { font-weight: 800; cursor: pointer; }
details p { color: var(--muted); margin: 12px 0 0; }
.contact-strip { padding-top: 30px; }
.strip-inner { border-radius: 34px; padding: 30px; display: flex; align-items: center; justify-content: space-between; gap: 20px; background: linear-gradient(135deg, var(--blue), var(--yellow)); }
.strip-inner h2 { margin: 10px 0; }
.page-hero { padding: 72px 0 46px; background: linear-gradient(135deg, rgba(223,243,255,0.7), rgba(255,250,240,0.88)); }
.filter-wrap { display: flex; align-items: end; justify-content: space-between; gap: 24px; margin-bottom: 24px; }
.filter-buttons { display: flex; gap: 10px; flex-wrap: wrap; }
.filter-buttons button { border: 1px solid var(--line); background: #fff; padding: 9px 14px; border-radius: 999px; cursor: pointer; color: #4f6675; font-weight: 800; }
.filter-buttons button.active { background: var(--orange-soft); color: #6a3c0f; }
.age-guide-list { display: grid; grid-template-columns: 1fr; gap: 18px; }
.age-guide-list article { display: grid; grid-template-columns: 110px 1fr 1.4fr auto; gap: 22px; align-items: center; }
.notice-box, .domain-box { margin-top: 22px; padding: 17px; border-radius: 20px; background: #fff; border: 1px solid #ccebf9; color: #1f6d94; font-weight: 800; word-break: break-all; }
.parent-steps article span { width: 48px; height: 48px; border-radius: 18px; display: grid; place-items: center; background: var(--yellow); color: #8f5d12; font-weight: 900; }
.video-cover { position: relative; border-radius: 24px; overflow: hidden; background: #f8fcff; margin-bottom: 18px; }
.video-cover span { position: absolute; right: 14px; bottom: 12px; border-radius: 999px; background: rgba(35,49,61,0.78); color: #fff; padding: 4px 10px; font-size: 13px; }
.contact-grid { grid-template-columns: 1.1fr 0.9fr; align-items: start; }
.contact-form { display: grid; gap: 16px; }
.contact-form label { display: grid; gap: 7px; font-weight: 800; }
input, select, textarea { width: 100%; border: 1px solid var(--line); border-radius: 18px; padding: 12px 14px; font: inherit; color: var(--ink); background: #fff; }
textarea { resize: vertical; }
.check-list { margin: 14px 0 0; padding-left: 20px; color: var(--muted); }
.site-footer { background: #23313d; color: #f8fcff; padding: 54px 0 24px; }
.footer-grid { display: grid; grid-template-columns: 1.4fr 0.7fr 0.9fr; gap: 36px; }
.footer-grid p, .footer-bottom p { color: rgba(248,252,255,0.72); margin: 10px 0; }
.footer-grid h2 { font-size: 18px; margin: 0 0 12px; }
.footer-grid a:not(.brand) { display: block; color: rgba(248,252,255,0.82); margin: 6px 0; }
.footer-brand small { color: rgba(248,252,255,0.68); }
.footer-bottom { border-top: 1px solid rgba(255,255,255,0.12); margin-top: 32px; padding-top: 18px; }
@media (max-width: 980px) {
    .hero-grid, .page-hero-grid, .split, .reverse, .contact-grid { grid-template-columns: 1fr; }
    .age-grid, .content-grid.three, .safe-grid, .values-grid, .parent-steps, .video-grid, .footer-grid { grid-template-columns: repeat(2, 1fr); }
    .age-guide-list article { grid-template-columns: 1fr; }
    .filter-wrap, .topic-card, .strip-inner { align-items: flex-start; flex-direction: column; }
}
@media (max-width: 760px) {
    .nav-toggle { display: inline-grid; place-items: center; }
    .site-nav { position: absolute; top: 76px; left: 18px; right: 18px; display: none; flex-direction: column; align-items: stretch; background: #fff; padding: 14px; border-radius: 22px; box-shadow: var(--shadow); border: 1px solid var(--line); }
    .site-nav.open { display: flex; }
    .site-nav a { text-align: center; }
    .hero { padding-top: 52px; }
    .age-grid, .content-grid.three, .safe-grid, .values-grid, .parent-steps, .video-grid, .quote-grid, .footer-grid { grid-template-columns: 1fr; }
    .hero-copy h1, .page-hero h1 { letter-spacing: -0.035em; }
    .mini-list div { display: block; }
    .mini-list span { display: block; margin-top: 4px; }
}