/* Happyplace — aurora lab theme. Cool lavender ground, violet→pink→cyan gradients,
   soft rounded tiles, "field notes" module bands and a featured strip. */
:root {
  --ink: #1b1733;
  --ink-2: #2a2450;
  --slate: #4a4470;
  --muted: #6f6a90;
  --violet: #6d5efc;
  --violet-dk: #4a3ce0;
  --pink: #ef5ba1;
  --cyan: #1fc4d8;
  --bg: #f6f6fd;
  --bg-2: #ecebfb;
  --card: #ffffff;
  --line: #e3e1f4;
  --line-2: #d3d0ee;
  --grad: linear-gradient(100deg, var(--violet) 0%, var(--pink) 55%, var(--cyan) 100%);
  --mono: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0; font-family: var(--sans); color: var(--ink);
  background: radial-gradient(1200px 520px at 80% -120px, #e9e6ff 0%, var(--bg) 60%);
  line-height: 1.65; font-size: 16px;
}
a { color: var(--violet-dk); text-decoration: none; }
a:hover { color: var(--pink); }
.wrap { max-width: 1100px; margin: 0 auto; padding: 0 20px; }

/* Header */
.site-header { background: rgba(255,255,255,0.86); backdrop-filter: blur(8px); border-bottom: 1px solid var(--line); position: sticky; top: 0; z-index: 5; }
.header-inner { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 12px; padding: 14px 0; }
.brand { display: flex; align-items: center; gap: 11px; color: var(--ink); }
.brand-mark { display: inline-flex; color: var(--violet); background: var(--grad); -webkit-background-clip: text; background-clip: text; }
.brand-mark svg { color: var(--violet); }
.brand-text { font-weight: 700; font-size: 22px; display: flex; flex-direction: column; line-height: 1; letter-spacing: -0.01em; }
.brand-sub { font-family: var(--mono); font-size: 11px; font-weight: 400; color: var(--muted); margin-top: 5px; }
.site-nav { display: flex; flex-wrap: wrap; gap: 3px; }
.nav-link { font-size: 13.5px; color: var(--slate); padding: 6px 11px; border-radius: 999px; }
.nav-link:hover { color: var(--violet-dk); background: var(--bg-2); }
.nav-link.is-active { color: #fff; background: var(--grad); }

/* Hero */
.hero { padding: 60px 0 30px; }
.hero-kicker { font-family: var(--mono); font-size: 12px; letter-spacing: 0.16em; text-transform: uppercase; color: var(--violet); margin: 0 0 12px; }
.hero-title { font-size: 46px; line-height: 1.05; margin: 0 0 14px; color: var(--ink); letter-spacing: -0.025em; max-width: 20ch; }
.hero-lede { font-size: 18px; color: var(--slate); max-width: 60ch; margin: 0 0 16px; }
.hero-note { font-size: 14px; color: var(--ink-2); background: #fff; border: 1px solid var(--line); border-left: 4px solid; border-image: var(--grad) 1; padding: 10px 14px; max-width: 60ch; margin: 0; }

/* Section label */
.section-label { font-size: 20px; color: var(--ink); margin: 0 0 16px; letter-spacing: -0.01em; }

/* Featured strip */
.start { padding: 14px 0 8px; }
.feats { display: grid; grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); gap: 16px; }
.feat { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 2px; background-image: var(--grad); background-size: 100% 4px; background-repeat: no-repeat; }
.feat-link { display: block; background: var(--card); border-radius: 14px; padding: 18px 18px 16px; }
.feat-num { font-family: var(--mono); font-size: 12px; color: var(--violet); }
.feat-title { margin: 6px 0 8px; font-size: 20px; color: var(--ink); line-height: 1.2; }
.feat-link:hover .feat-title { color: var(--violet-dk); }
.feat-desc { margin: 0 0 12px; font-size: 14px; color: var(--muted); }
.feat-foot { display: flex; align-items: center; gap: 8px; }
.feat-area { font-family: var(--mono); font-size: 11px; color: var(--muted); }

/* Modules */
.modules { padding: 24px 0 56px; }
.module { margin: 30px 0; }
.module-head { display: flex; gap: 12px; align-items: flex-start; margin-bottom: 14px; }
.module-dot { width: 12px; height: 12px; border-radius: 50%; background: var(--grad); margin-top: 8px; flex: none; }
.module-name { margin: 0 0 3px; font-size: 22px; letter-spacing: -0.01em; }
.module-name a { color: var(--ink); }
.module-name a:hover { color: var(--violet-dk); }
.module-blurb { margin: 0; font-size: 14px; color: var(--muted); max-width: 68ch; }
.tiles { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 14px; }
.tiles-wide { padding-bottom: 56px; }
.tile { background: var(--card); border: 1px solid var(--line); border-radius: 14px; transition: box-shadow .15s, transform .15s; }
.tile:hover { box-shadow: 0 12px 28px -18px rgba(74,60,224,.5); transform: translateY(-2px); }
.tile-link { display: block; padding: 16px 16px 14px; }
.tile-mod { font-family: var(--mono); font-size: 10.5px; text-transform: uppercase; letter-spacing: 0.1em; color: var(--violet); }
.tile-title { margin: 6px 0 7px; font-size: 18px; color: var(--ink); line-height: 1.22; }
.tile-link:hover .tile-title { color: var(--violet-dk); }
.tile-desc { margin: 0 0 12px; font-size: 13.5px; color: var(--muted); }
.tile-foot { display: flex; align-items: center; gap: 8px; }
.tile-area { font-family: var(--mono); font-size: 11px; color: var(--muted); }

/* Level chips */
.chip-level { font-family: var(--mono); font-size: 11px; padding: 3px 9px; border-radius: 999px; }
.lv-beginner { color: #0a7a45; background: #e2f7ec; }
.lv-intermediate { color: #9a5a12; background: #fdeedb; }

/* Category header */
.crumb { font-family: var(--mono); font-size: 12px; color: var(--muted); padding-top: 24px; }
.crumb a { color: var(--slate); } .crumb a:hover { color: var(--violet-dk); }
.crumb .sep { margin: 0 7px; color: var(--line-2); }
.mod-head { padding: 20px 0 18px; }
.mod-title { font-size: 36px; color: var(--ink); margin: 6px 0 10px; letter-spacing: -0.02em; }
.mod-blurb { font-size: 17px; color: var(--slate); max-width: 62ch; margin: 0; }

/* Topic page */
.topic { max-width: 790px; margin: 0 auto; padding-bottom: 56px; }
.topic-head { padding: 18px 0 8px; }
.topic-title { font-size: 36px; line-height: 1.13; color: var(--ink); margin: 4px 0 6px; letter-spacing: -0.02em; }
.topic-zh { font-family: var(--mono); font-size: 14px; color: var(--muted); margin: 0; }

/* Glance card */
.glance { background: var(--card); border: 1px solid var(--line); border-radius: 16px; padding: 16px 20px; margin: 22px 0 10px; border-top: 4px solid; border-image: var(--grad) 1; }
.glance-label { font-family: var(--mono); font-size: 11px; text-transform: uppercase; letter-spacing: 0.14em; color: var(--violet); margin: 0 0 12px; }
.glance-list { display: grid; grid-template-columns: 150px 1fr; gap: 8px 18px; margin: 0; }
.glance-list dt { font-size: 13px; color: var(--muted); font-weight: 600; }
.glance-list dd { margin: 0; font-size: 14.5px; color: var(--ink); }

/* Sections */
.sec { margin: 30px 0; }
.sec-heading { font-size: 21px; color: var(--ink); margin: 0 0 12px; padding-bottom: 8px; border-bottom: 2px solid var(--line); }
.sec-num { font-family: var(--mono); font-size: 14px; color: var(--violet); }
.sec-body p { margin: 0 0 14px; }
.sec-body p:last-child { margin-bottom: 0; }

/* Related */
.related { margin: 36px 0 40px; }
.rel-tiles { display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr)); gap: 12px; }
.rel-tile { display: flex; flex-direction: column; gap: 5px; background: var(--card); border: 1px solid var(--line); border-radius: 12px; padding: 13px 15px; }
.rel-tile:hover { border-color: var(--pink); }
.rel-title { font-weight: 600; color: var(--ink); font-size: 15px; }
.rel-meta { font-family: var(--mono); font-size: 11px; color: var(--muted); }
.rel-tile.is-drip { opacity: 0.55; }

/* Legal */
.legal { max-width: 760px; margin: 0 auto; padding: 40px 0 56px; }
.legal-title { font-size: 32px; color: var(--ink); margin: 0 0 18px; }
.legal-body h2 { font-size: 20px; color: var(--ink); margin: 24px 0 8px; }
.legal-body p { margin: 0 0 14px; }
.legal-body a { word-break: break-all; }

/* 404 */
.nf { padding: 70px 0 80px; }
.nf-title { font-size: 32px; color: var(--ink); margin: 0 0 12px; }
.nf-body { color: var(--muted); margin: 0 0 22px; max-width: 50ch; }
.nf-link { display: inline-block; padding: 11px 20px; border-radius: 999px; background: var(--grad); color: #fff; font-weight: 600; }
.nf-link:hover { color: #fff; opacity: .9; }

/* Footer */
.site-footer { background: var(--ink); color: #c9c5e8; margin-top: 24px; }
.site-footer .wrap { padding-top: 26px; padding-bottom: 26px; }
.foot-brand { font-weight: 700; color: #fff; margin: 0 0 8px; }
.foot-links { margin: 0 0 10px; font-size: 14px; }
.foot-links a { color: #a9a3db; margin: 0 4px; }
.foot-links a:hover { color: #fff; }
.foot-note { margin: 0; font-size: 13px; color: #9691c0; max-width: 68ch; }

@media (max-width: 640px) {
  .hero-title { font-size: 32px; }
  .topic-title, .mod-title { font-size: 27px; }
  .header-inner { flex-direction: column; align-items: flex-start; }
  .glance-list { grid-template-columns: 1fr; gap: 2px; }
  .glance-list dt { margin-top: 8px; }
}