/* 有心 Yausum — coming-soon page. One origin, system fonts, no third-party requests. */
:root {
  --bg: #05090E;
  --bg2: #08111A;
  --panel: rgba(10, 20, 30, .78);
  --panel-solid: #0B1520;
  --line: rgba(120, 190, 230, .16);
  --line2: rgba(83, 183, 232, .38);
  --ink: #E8F1F7;
  --mute: #9AB0C0;
  --dim: #647A8B;
  --blue: #53B7E8;
  --blue-hi: #A6DCF4;
  --warm: #FFE3A0;
  --red: #E2231A;
  --kw: #7FD0F5;
  --name: #FFD58A;
  --text: #9EE6B8;
  --num: #F5A8C8;
  --punct: #6F8799;
  --serif: "Songti TC", "Noto Serif TC", "Source Han Serif TC", "PMingLiU", "MingLiU", serif;
  --sans: system-ui, -apple-system, "PingFang TC", "Microsoft JhengHei", "Noto Sans TC", "Segoe UI", Roboto, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, "PingFang TC", "Microsoft JhengHei", monospace;
  --gutter: clamp(16px, 4vw, 40px);
  --maxw: 1180px;
  color-scheme: dark;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; scroll-padding-top: 96px; }
body { margin: 0; background: var(--bg); color: var(--ink); font: 17px/1.7 var(--sans); -webkit-font-smoothing: antialiased; overflow-x: hidden; }
img, video { max-width: 100%; display: block; }
a { color: var(--blue-hi); }
.en { font-family: var(--sans); }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }
.skip { position: absolute; left: -999px; top: 8px; z-index: 50; padding: 8px 14px; background: var(--blue); color: #001; border-radius: 8px; }
.skip:focus { left: 8px; }
:focus-visible { outline: 2px solid var(--blue); outline-offset: 3px; border-radius: 6px; }
.wrap { max-width: var(--maxw); margin: 0 auto; padding: 0 var(--gutter); }

/* ---------- header ---------- */
.top { position: fixed; inset: 0 0 auto 0; z-index: 20; background: rgba(5, 9, 14, .72); backdrop-filter: blur(14px) saturate(140%); -webkit-backdrop-filter: blur(14px) saturate(140%); border-bottom: 1px solid var(--line); }
.top-bar { max-width: var(--maxw); margin: 0 auto; padding: 10px var(--gutter); display: flex; align-items: center; justify-content: space-between; gap: 12px; }
.brand { display: flex; align-items: center; gap: 10px; color: var(--ink); text-decoration: none; }
.brand img { border-radius: 7px; }
.brand-zh { font: 600 22px/1 var(--serif); letter-spacing: .08em; }
.brand-en { font: 500 13px/1 var(--mono); color: var(--mute); letter-spacing: .14em; text-transform: uppercase; }
.chip { display: inline-flex; align-items: center; gap: 8px; padding: 6px 12px; border: 1px solid var(--line2); border-radius: 999px; font-size: 14px; color: var(--blue-hi); background: rgba(83, 183, 232, .07); white-space: nowrap; }
.dot { width: 8px; height: 8px; border-radius: 50%; background: var(--blue); box-shadow: 0 0 0 0 rgba(83, 183, 232, .7); animation: pulse 2.2s infinite; }
@keyframes pulse { 0% { box-shadow: 0 0 0 0 rgba(83,183,232,.7); } 70% { box-shadow: 0 0 0 9px rgba(83,183,232,0); } 100% { box-shadow: 0 0 0 0 rgba(83,183,232,0); } }
.ticker { overflow: hidden; border-top: 1px solid var(--line); background: #03070B; height: 30px; }
.ticker-track { display: flex; width: max-content; animation: ticker 48s linear infinite; }
.ticker-track span { font: 500 13px/30px var(--mono); color: #F7B54A; letter-spacing: .12em; padding: 0 28px; white-space: nowrap; text-shadow: 0 0 8px rgba(247, 181, 74, .45); }
.ticker-track span:nth-child(even) { color: var(--blue-hi); text-shadow: 0 0 8px rgba(83, 183, 232, .45); }
.ticker-track span::before { content: "◆"; font-size: 8px; margin-right: 28px; color: var(--dim); text-shadow: none; vertical-align: 2px; }
@keyframes ticker { to { transform: translateX(-50%); } }

/* ---------- hero ---------- */
.hero { position: relative; min-height: 100svh; display: flex; align-items: center; overflow: hidden; text-align: center;
  background:
    radial-gradient(ellipse 60% 46% at 50% 36%, rgba(83, 183, 232, .22), rgba(83, 183, 232, 0) 70%),
    url("/assets/tiles-night.webp") center top / 600px; }
.hero::after { content: ""; position: absolute; inset: 0; background: radial-gradient(ellipse 90% 80% at 50% 40%, rgba(5,9,14,0) 40%, rgba(5,9,14,.75) 100%), linear-gradient(180deg, rgba(5,9,14,0) 70%, var(--bg) 100%); pointer-events: none; }
.hero-sweep { position: absolute; inset: 0; z-index: 1; pointer-events: none; background: linear-gradient(105deg, transparent 40%, rgba(166, 220, 244, .07) 50%, transparent 60%); background-size: 250% 100%; animation: sweep 9s ease-in-out infinite; }
@keyframes sweep { 0% { background-position: 120% 0; } 60%, 100% { background-position: -20% 0; } }
.hero-inner { position: relative; z-index: 2; width: 100%; max-width: var(--maxw); margin: 0 auto; padding: 120px var(--gutter) clamp(48px, 8vh, 88px); display: flex; flex-direction: column; align-items: center; }
.sign { margin: 0 0 6px; width: min(560px, 82vw); }
.sign img { width: 100%; height: auto; }
.eyebrow { margin: 0 0 14px; font: 500 13px/1.5 var(--mono); letter-spacing: .16em; color: var(--blue-hi); text-transform: uppercase; }
.eyebrow .sep { color: var(--dim); margin: 0 6px; }
.headline { margin: 0; font: 600 clamp(38px, 6.4vw, 76px)/1.15 var(--serif); letter-spacing: .06em; text-shadow: 0 0 40px rgba(83, 183, 232, .35); }
.headline-en { margin: 6px 0 22px; font: 300 clamp(20px, 2.6vw, 30px)/1.3 var(--sans); color: var(--blue-hi); letter-spacing: .02em; }
.lede { margin: 0 auto; max-width: 40em; font-size: clamp(17px, 1.6vw, 19px); }
.lede.en { color: var(--mute); margin-top: 4px; font-size: 16px; }
.cta { display: flex; flex-wrap: wrap; justify-content: center; gap: 12px; margin-top: 30px; }
.btn { display: inline-flex; align-items: center; gap: 8px; padding: 12px 20px; border-radius: 10px; border: 1px solid var(--line2); color: var(--ink); text-decoration: none; background: rgba(10, 20, 30, .6); font-weight: 600; transition: background .2s, border-color .2s, transform .2s; }
.btn .en { font-weight: 400; color: var(--mute); }
.btn:hover { border-color: var(--blue); background: rgba(83, 183, 232, .12); transform: translateY(-1px); }
.btn.primary { background: var(--blue); border-color: var(--blue); color: #021018; }
.btn.primary .en { color: #0B3348; }
.btn.primary:hover { background: #6CC4EE; }

/* ---------- sections ---------- */
.section { position: relative; padding: clamp(72px, 11vw, 132px) 0; border-top: 1px solid var(--line); }
.section.tiles { background: linear-gradient(180deg, var(--bg) 0%, rgba(5,9,14,.86) 18%, rgba(5,9,14,.86) 82%, var(--bg) 100%), url("/assets/tiles-night.webp") 0 0 / 600px; }
.kicker { margin: 0 0 10px; font: 500 13px/1.4 var(--mono); letter-spacing: .16em; text-transform: uppercase; color: var(--blue); }
.kicker .num { display: inline-block; padding: 2px 7px; margin-right: 10px; border: 1px solid var(--line2); border-radius: 5px; color: var(--blue-hi); }
.kicker .en { color: var(--dim); }
h2 { margin: 0 0 18px; font: 600 clamp(30px, 4.4vw, 48px)/1.25 var(--serif); letter-spacing: .04em; }
h2 .en { display: block; margin-top: 8px; font: 300 clamp(17px, 2vw, 22px)/1.4 var(--sans); letter-spacing: 0; color: var(--mute); }
.intro { margin: 0; max-width: 46em; font-size: 18px; }
.intro.en { margin-top: 4px; color: var(--mute); font-size: 16px; }
.note { margin: 26px 0 0; color: var(--mute); font-size: 15px; }
.note .en { display: block; color: var(--dim); font-size: 14px; }

/* video "door display" frame */
.screen { margin: 34px 0 0; border: 1px solid var(--line2); border-radius: 16px; overflow: hidden; background: #03070B; box-shadow: 0 30px 80px -30px rgba(83, 183, 232, .35), 0 0 0 6px rgba(83, 183, 232, .04); }
.screen-bar { display: flex; align-items: center; gap: 14px; padding: 10px 16px; background: #0D141B; border-bottom: 1px solid #1E2A35; }
.screen-line { width: 6px; align-self: stretch; border-radius: 3px; background: var(--blue); }
.screen-label { display: flex; flex-direction: column; font: 600 15px/1.2 var(--serif); color: #C9D6E0; }
.screen-label small, .screen-name small { font: 500 11px/1.3 var(--mono); letter-spacing: .1em; color: var(--blue-hi); }
.screen-dot { margin-left: auto; width: 9px; height: 9px; border-radius: 50%; background: var(--red); box-shadow: 0 0 10px var(--red); animation: blink 1s steps(2, start) infinite; }
@keyframes blink { to { visibility: hidden; } }
.screen-name { display: flex; flex-direction: column; align-items: flex-end; font: 600 24px/1.1 var(--serif); letter-spacing: .08em; }
.screen-video { position: relative; aspect-ratio: 16 / 9; background: #53B7E8; }
.screen-video video { width: 100%; height: 100%; object-fit: cover; }
.vbtn { position: absolute; bottom: 14px; display: inline-flex; align-items: center; gap: 6px; padding: 9px 14px; border: 1px solid rgba(255,255,255,.18); border-radius: 999px; cursor: pointer; background: rgba(5, 9, 14, .72); color: #fff; font: 600 14px/1 var(--sans); backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px); }
.vbtn .en { font-weight: 400; color: #C8D6E0; }
.vbtn:hover { background: rgba(5, 9, 14, .92); border-color: var(--blue); }
.vbar { position: absolute; right: 14px; bottom: 14px; display: flex; gap: 8px; }
.vbar .vbtn { position: static; }
.vbtn[aria-pressed="true"].cc { border-color: var(--blue); }
.vcap { position: absolute; left: 50%; bottom: 64px; transform: translateX(-50%); width: max-content; max-width: 88%; display: flex; flex-direction: column; align-items: center; gap: 4px; pointer-events: none; }
.vcap.top { top: 14px; bottom: auto; left: 14px; transform: none; align-items: flex-start; }
.vcap.top p { text-align: left; }
.vcap[hidden] { display: none; }
.screen-video:fullscreen { aspect-ratio: auto; width: 100%; height: 100%; background: #000; }
.screen-video:-webkit-full-screen { aspect-ratio: auto; width: 100%; height: 100%; background: #000; }
.screen-video:fullscreen video { object-fit: contain; }
.screen-video:-webkit-full-screen video { object-fit: contain; }
.screen-video:fullscreen .vcap p { font-size: clamp(16px, 2.2vw, 30px); }
.vcap p { margin: 0; padding: 5px 12px; border-radius: 6px; background: rgba(5, 9, 14, .8); color: #fff; text-align: center; font: 600 clamp(13px, 2.1vw, 19px)/1.35 var(--sans); }
.vcap p .en { display: block; font-weight: 400; color: #DCE7EF; }
.vbtn.replay { left: 14px; }
.vbtn[hidden] { display: none; }
.screen figcaption { padding: 12px 16px; font-size: 14px; color: var(--mute); background: #0B1219; border-top: 1px solid #16212B; }
.screen figcaption .en { margin-left: 8px; color: var(--dim); }

/* code tabs */
.tabs { display: flex; flex-wrap: wrap; gap: 8px; margin: 34px 0 16px; }
.tabs [role="tab"] { padding: 9px 16px; border-radius: 10px; border: 1px solid var(--line); background: rgba(10, 20, 30, .7); color: var(--mute); font: 600 15px/1.3 var(--sans); cursor: pointer; }
.tabs [role="tab"] .en { font-weight: 400; color: var(--dim); margin-left: 4px; }
.tabs [role="tab"][aria-selected="true"] { border-color: var(--blue); color: var(--ink); background: rgba(83, 183, 232, .12); box-shadow: inset 0 -2px 0 var(--blue); }
.tabs [role="tab"]:hover { color: var(--ink); }
.panel { display: grid; grid-template-columns: minmax(0, 1.6fr) minmax(0, 1fr); gap: 16px; align-items: start; }
.panel + .panel { margin-top: 16px; }
.js .panel[hidden] { display: none; }
.code-card, .out-card, .term { border: 1px solid var(--line); border-radius: 14px; background: var(--panel); overflow: hidden; backdrop-filter: blur(6px); -webkit-backdrop-filter: blur(6px); }
.card-bar { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 6px 16px; padding: 10px 16px; border-bottom: 1px solid var(--line); background: rgba(3, 7, 11, .6); font: 13px/1.4 var(--mono); }
.card-bar .file { color: var(--ink); }
.card-bar .file .en { color: var(--dim); }
.card-bar .cmd { color: var(--dim); }
pre { margin: 0; padding: 18px 20px; overflow-x: auto; font: 15.5px/1.8 var(--mono); tab-size: 4; }
pre.out { color: #D6E4EE; }
.out-card { position: sticky; top: 110px; }
.out-card pre::before { content: ""; }
.ys .k { color: var(--kw); }
.ys .n { color: var(--name); }
.ys .t { color: var(--text); }
.ys .t .n { color: var(--name); }
.ys .d { color: var(--num); }
.ys .p { color: var(--punct); }
.ys .c { color: var(--dim); font-style: italic; }

/* errors */
.err-grid { display: grid; grid-template-columns: minmax(0, 1.25fr) minmax(0, 1fr); gap: 16px; margin-top: 34px; align-items: start; }
.term-body { padding: 18px 20px; font: 15.5px/1.75 var(--mono); }
.term-body p { margin: 0; }
.e-head { color: #FFB4AB; font-weight: 600; }
.e-head .e-tag { color: #FF6B5E; }
.e-head.en, .e-hint.en { color: var(--mute); font-weight: 400; }
.e-head.en .e-tag { color: #E59088; }
.e-loc { color: var(--blue); margin: 6px 0 8px !important; }
.e-src { padding: 6px 12px; margin: 2px 0 !important; border-left: 2px solid var(--line2); background: rgba(83, 183, 232, .05); }
.e-src .ln { display: inline-block; width: 2ch; margin-right: 14px; color: var(--dim); }
.wavy { text-decoration: underline wavy #FF6B5E; text-decoration-thickness: 1.5px; text-underline-offset: 6px; color: #FFD2CC; }
.wavy.ws { color: #FF6B5E; letter-spacing: .1em; }
.e-hint { margin-top: 10px !important; color: #CDE8C4; }
.e-hint b { color: var(--text); }
.e-hint.en { margin-top: 2px !important; }

/* goals */
.goals { display: grid; grid-template-columns: repeat(4, minmax(0, 1fr)); gap: 16px; margin-top: 38px; }
.goal { position: relative; padding: 26px 22px 24px; border: 1px solid var(--line); border-radius: 14px; background: var(--panel); overflow: hidden; }
.goal::before { content: ""; position: absolute; inset: 0 0 auto 0; height: 2px; background: linear-gradient(90deg, var(--blue), transparent); }
.goal-no { font: 500 12px/1 var(--mono); color: var(--blue); letter-spacing: .14em; }
.goal h3 { margin: 12px 0 10px; font: 600 22px/1.3 var(--serif); letter-spacing: .04em; }
.goal h3 .en { display: block; margin-top: 4px; font: 500 14px/1.3 var(--sans); color: var(--blue-hi); letter-spacing: 0; }
.goal p { margin: 0; font-size: 15.5px; }
.goal p.en { margin-top: 8px; color: var(--mute); font-size: 14px; line-height: 1.6; }

/* learn */
.learn { display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 1fr); gap: clamp(28px, 5vw, 64px); align-items: center; }
.quote { margin: 26px 0 0; padding: 18px 22px; border-left: 3px solid var(--blue); background: rgba(83, 183, 232, .06); border-radius: 0 12px 12px 0; }
.quote p { margin: 0; font: 500 20px/1.6 var(--serif); }
.quote p.en { margin-top: 6px; font: 15px/1.6 var(--sans); color: var(--mute); }
.facts { list-style: none; margin: 0; padding: 0; display: grid; gap: 12px; }
.facts li { padding: 18px 20px 18px 54px; position: relative; border: 1px solid var(--line); border-radius: 14px; background: var(--panel); }
.facts li::before { content: "心"; position: absolute; left: 16px; top: 17px; width: 26px; height: 26px; display: grid; place-items: center; border-radius: 6px; background: var(--blue); color: #fff; font: 600 15px/1 var(--serif); }
.facts b { display: block; font: 600 17px/1.5 var(--serif); }
.facts .en { display: block; margin-top: 4px; color: var(--mute); font-size: 14.5px; }

/* arriving */
.arrive { position: relative; padding: clamp(64px, 10vw, 120px) 0 clamp(80px, 12vw, 140px); text-align: center; color: #fff; border-top: 1px solid var(--line);
  background: linear-gradient(180deg, rgba(5,9,14,.18), rgba(5,9,14,0) 35%, rgba(5,9,14,.35)), url("/assets/tiles-day.webp") center / 600px; }
.arrive-sign { display: block; width: min(520px, 80vw); margin: 0 auto 18px; }
.arrive-sign img { width: 100%; height: auto; }
.arrive h2 { font-size: clamp(34px, 5.6vw, 60px); text-shadow: 0 4px 30px rgba(0, 30, 50, .5); }
.arrive h2 .en { color: #E8F6FF; }
.arrive p { margin: 0; font-size: 18px; text-shadow: 0 2px 14px rgba(0, 30, 50, .6); }
.arrive p:not(.kicker) .en { display: block; color: #E2F2FB; font-size: 16px; }
.kicker.light, .kicker.light .en { color: #fff; }
.kicker.light .num { border-color: rgba(255,255,255,.6); color: #fff; }

/* footer */
.foot { border-top: 1px solid var(--line); padding: 34px 0 calc(34px + env(safe-area-inset-bottom)); background: #03070B; }
.foot-inner { display: grid; gap: 6px; }
.foot p { margin: 0; font-size: 14px; }
.foot-brand { display: flex; align-items: center; gap: 8px; font: 600 16px/1.4 var(--serif) !important; }
.foot-brand img { border-radius: 5px; }
.dim { color: var(--dim); }
.foot .en { margin-left: 6px; }
.foot a { color: var(--mute); }

/* ---------- responsive ---------- */
@media (max-width: 1000px) {
  .goals { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .panel, .err-grid, .learn { grid-template-columns: minmax(0, 1fr); }
  .out-card { position: static; }
}
@media (max-width: 760px) {
  body { font-size: 16px; }
  .hero-inner { padding-top: 104px; }
  .chip .en, .brand-en { display: none; }
  .eyebrow .en { display: block; margin-top: 4px; }
  .eyebrow .sep { display: none; }
  .goals { grid-template-columns: minmax(0, 1fr); }
  pre, .term-body { font-size: 14px; padding: 14px 16px; }
  .card-bar .cmd { width: 100%; }
  .screen-name { font-size: 20px; }
  .vbtn { padding: 8px 12px; font-size: 13px; bottom: 10px; }
  .vbar { right: 8px; bottom: 8px; gap: 6px; }
  .vbar .vbtn { padding: 6px 9px; font-size: 12px; }
  .vbar .vbtn .zh { display: none; }
  .vbtn.cc .en { display: inline; color: #fff; font-weight: 600; }
  .vcap { bottom: 46px; max-width: 94%; gap: 2px; }
  .vcap.top { top: 8px; left: 8px; }
  .vcap p { padding: 2px 7px; border-radius: 4px; font-size: 11px; }
  .vcap p .en { font-size: 10px; }
  .vbtn .en { display: none; }
}
@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .ticker-track, .hero-sweep, .dot, .screen-dot { animation: none; }
  .btn { transition: none; }
}

/* 404 */
.hero.lost { align-items: center; text-align: left; }
.hero.lost .hero-inner { align-items: flex-start; }
.hero.lost .hero-inner { padding-bottom: 0; }
/* the bottom-right buttons appear while the pointer is over the video (or a button has keyboard focus); touch screens, which cannot hover, always show them */
@media (hover: hover) {
  .vbar { opacity: 0; transition: opacity .2s; }
  .screen-video:hover .vbar, .vbar:focus-within { opacity: 1; }
}