:root {
  color-scheme: dark;
  --bg: var(--echo-ground);
  --panel: var(--echo-surface);
  --line: var(--echo-line);
  --line-strong: var(--echo-line-strong);
  --text: var(--echo-ink);
  --muted: var(--echo-ink-muted);
  --dim: var(--echo-ink-faint);
  --blue: var(--echo-ink-muted);
  --violet: var(--echo-ink-muted);
  --cyan: var(--echo-core);
  --green: var(--echo-core);
  --amber: var(--echo-warning);
  --gutter: clamp(22px, 5vw, 78px);
  --content: 1180px;
  --mono: var(--echo-font-telemetry);
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body { margin: 0; min-width: 320px; color: var(--text); background: var(--bg); font-family: var(--echo-font-sans); -webkit-font-smoothing: antialiased; }
a { color: inherit; text-decoration: none; }
button, input, select { font: inherit; }
code, pre { font-family: var(--mono); }

.sr-only { position: absolute; width: 1px; height: 1px; margin: -1px; padding: 0; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; border: 0; }
.skip-link { position: absolute; z-index: 100; left: 16px; top: -60px; padding: 10px 16px; color: var(--echo-surface); background: var(--cyan); border-radius: 6px; font-size: 12px; transition: top .2s ease; }
.skip-link:focus { top: 14px; }
a:focus-visible, button:focus-visible, input:focus-visible, select:focus-visible { outline: 1px solid var(--cyan); outline-offset: 3px; }

.dev-header { position: fixed; z-index: 50; top: 0; left: 50%; width: min(calc(100% - var(--gutter) * 2), var(--content)); height: 74px; transform: translateX(-50%); display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; }
.dev-header::before { content: ""; position: absolute; z-index: -1; inset: 0 calc(var(--gutter) * -1); background: linear-gradient(180deg, rgba(9, 10, 12, .96), rgba(9, 10, 12, .3) 74%, transparent); }
.dev-header.is-scrolled::before { backdrop-filter: blur(14px); border-bottom: 1px solid var(--line); }
.dev-brand { display: flex; align-items: baseline; gap: 9px; width: max-content; }
.dev-brand strong { font-size: 14px; font-weight: 520; letter-spacing: .32em; }
.dev-brand span { color: var(--echo-ink-muted); font-size: 8px; letter-spacing: .2em; }
.dev-nav { display: flex; justify-content: center; gap: clamp(20px, 3vw, 42px); }
.dev-nav a { position: relative; color: var(--echo-ink-muted); font-size: 9px; letter-spacing: .14em; text-transform: uppercase; white-space: nowrap; transition: color .2s ease; }
.dev-nav a::after { content: ""; position: absolute; left: 0; right: 100%; bottom: -5px; height: 1px; background: linear-gradient(90deg, var(--blue), var(--violet)); transition: right .25s ease; }
.dev-nav a:hover, .dev-nav a.active { color: var(--echo-ink); text-shadow: none; }
.dev-nav a:hover::after, .dev-nav a.active::after { right: 0; }
.dev-actions { justify-self: end; display: flex; align-items: center; gap: 12px; }
.locale-switch { display: flex; align-items: center; gap: 2px; color: var(--echo-ink-faint); font-size: 9px; }
.locale-switch button { padding: 6px 4px; border: 0; color: var(--echo-ink-muted); background: transparent; font-size: 9px; cursor: pointer; }
.locale-switch button[aria-pressed="true"] { color: var(--echo-ink); }
.back-echo { min-width: 96px; height: 32px; padding: 0 13px; display: inline-flex; align-items: center; justify-content: center; border: 1px solid var(--line-strong); border-radius: var(--echo-radius-sm); color: var(--echo-ink); font-size: 9px; letter-spacing: .1em; transition: border-color .2s ease, background .2s ease; }
.back-echo:hover { border-color: rgba(238, 241, 244, .5); background: rgba(9, 10, 12, .8); }

main { width: min(calc(100% - var(--gutter) * 2), var(--content)); margin: 0 auto; }
.kicker { margin: 0 0 14px; color: var(--echo-ink-muted); font-size: 9px; letter-spacing: .26em; text-transform: uppercase; }
.dev-hero { padding: 168px 0 80px; border-bottom: 1px solid var(--line); }
.dev-hero h1 { margin: 0 0 22px; max-width: 15ch; font-size: clamp(40px, 6vw, 76px); font-weight: 200; line-height: 1.02; letter-spacing: -.01em; }
.lead { margin: 0; max-width: 60ch; color: var(--muted); font-size: clamp(14px, 1.3vw, 16px); line-height: 1.72; }
.hero-facts { margin-top: 46px; display: flex; flex-wrap: wrap; gap: 12px; }
.hero-facts span { flex: 1 1 168px; padding: 18px 20px; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); display: flex; flex-direction: column; gap: 7px; }
.hero-facts b { color: var(--echo-ink); font-size: 25px; font-weight: 250; letter-spacing: -.01em; }
.hero-facts small { color: var(--dim); font-size: 9px; letter-spacing: .16em; text-transform: uppercase; }

.dev-section { padding: 84px 0; border-bottom: 1px solid var(--line); }
.section-head { max-width: 68ch; margin-bottom: 40px; }
.section-head h2 { margin: 0 0 16px; font-size: clamp(27px, 3.1vw, 40px); font-weight: 240; line-height: 1.12; }
.section-body { margin: 0; color: var(--muted); font-size: 14px; line-height: 1.76; }
.note { margin: 22px 0 0; padding: 15px 18px; border-left: 2px solid var(--line-strong); color: var(--muted); font-size: 12.5px; line-height: 1.7; background: rgba(9, 10, 12, .5); border-radius: 0 8px 8px 0; }
.note.warn { border-left-color: var(--amber); }

.code-block { border: 1px solid var(--line); border-radius: 12px; background: rgba(9, 10, 12, .82); overflow: hidden; }
.code-top { padding: 10px 16px; display: flex; align-items: center; justify-content: space-between; border-bottom: 1px solid var(--line); color: var(--dim); font-size: 9px; letter-spacing: .18em; text-transform: uppercase; }
.copy-btn { padding: 6px 12px; border: 1px solid var(--line-strong); border-radius: var(--echo-radius-sm); color: var(--echo-ink); background: transparent; font-size: 9px; letter-spacing: .1em; cursor: pointer; transition: border-color .2s ease, color .2s ease; }
.copy-btn:hover { border-color: var(--cyan); color: var(--echo-ink); }
.copy-btn.copied { border-color: var(--green); color: var(--green); }
.code-block pre { margin: 0; padding: 18px 16px; overflow-x: auto; color: var(--echo-ink); font-size: 12.5px; line-height: 1.7; }

.tier-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 14px; }
.tier-card { padding: 24px 22px; border: 1px solid var(--line); border-radius: 14px; background: var(--panel); display: flex; flex-direction: column; gap: 11px; }
.tier-card h3 { margin: 0; font-size: 16px; font-weight: 420; }
.tier-card p { margin: 0; flex: 1; color: var(--muted); font-size: 12.5px; line-height: 1.7; }
.tier-card code { padding: 8px 11px; border-radius: var(--echo-radius-xs); background: rgba(9, 10, 12, .75); color: var(--echo-ink); font-size: 11px; word-break: break-all; }
.tier-index { font-size: 9px; letter-spacing: .2em; }
.tier-public .tier-index { color: var(--green); }
.tier-user .tier-index { color: var(--blue); }
.tier-admin .tier-index { color: var(--amber); }

.filter-row { margin-bottom: 18px; display: flex; align-items: center; gap: 12px; }
.filter-label { color: var(--dim); font-size: 9px; letter-spacing: .16em; text-transform: uppercase; }
#endpoint-filter { flex: 0 1 280px; padding: 10px 14px; border: 1px solid var(--line); border-radius: var(--echo-radius-sm); color: var(--text); background: rgba(9, 10, 12, .7); font-size: 12px; }
#endpoint-filter::placeholder { color: var(--echo-ink-faint); }
.table-wrap { border: 1px solid var(--line); border-radius: 12px; overflow-x: auto; }
.endpoint-table { width: 100%; border-collapse: collapse; font-size: 12.5px; }
.endpoint-table th { padding: 13px 16px; text-align: left; color: var(--dim); font-size: 9px; font-weight: 500; letter-spacing: .16em; text-transform: uppercase; background: rgba(9, 10, 12, .7); border-bottom: 1px solid var(--line); white-space: nowrap; }
.endpoint-table td { padding: 14px 16px; border-bottom: 1px solid rgba(238, 241, 244, .07); vertical-align: top; }
.endpoint-table tr:last-child td { border-bottom: 0; }
.endpoint-table tr:hover td { background: rgba(9, 10, 12, .5); }
.method { padding: 3px 9px; border-radius: 5px; font-family: var(--mono); font-size: 10px; letter-spacing: .06em; }
.method-get { color: var(--green); background: rgba(238, 241, 244, .12); }
.method-put { color: var(--amber); background: rgba(242, 184, 75, .12); }
.endpoint-table td.path { color: var(--echo-ink); font-family: var(--mono); font-size: 12px; word-break: break-all; }
.endpoint-table td.desc { color: var(--muted); line-height: 1.66; min-width: 200px; }
.empty-hint { margin: 18px 0 0; color: var(--dim); font-size: 12.5px; }

.play-controls { margin-bottom: 16px; display: flex; flex-wrap: wrap; gap: 11px; }
#play-endpoint { flex: 1 1 360px; padding: 11px 14px; border: 1px solid var(--line); border-radius: 9px; color: var(--text); background: rgba(9, 10, 12, .8); font-family: var(--mono); font-size: 12px; }
.send-btn { padding: 11px 24px; border: 1px solid var(--line-strong); border-radius: var(--echo-radius-sm); color: var(--echo-ink); background: rgba(27, 30, 35, .7); font-size: 11px; letter-spacing: .12em; cursor: pointer; transition: border-color .2s ease, background .2s ease; }
.send-btn:hover { border-color: var(--cyan); background: rgba(34, 39, 46, .85); }
.send-btn[disabled] { opacity: .5; cursor: progress; }
.play-result { border: 1px solid var(--line); border-radius: 12px; background: rgba(9, 10, 12, .82); overflow: hidden; }
.result-top { padding: 11px 16px; display: flex; align-items: center; justify-content: space-between; gap: 12px; border-bottom: 1px solid var(--line); font-size: 10px; letter-spacing: .12em; text-transform: uppercase; }
.result-status { color: var(--dim); }
.result-status.ok { color: var(--green); }
.result-status.err { color: var(--echo-breach); }
.result-time { color: var(--dim); font-family: var(--mono); }
.play-result pre { margin: 0; padding: 18px 16px; max-height: 380px; overflow: auto; color: var(--echo-ink); font-size: 12px; line-height: 1.66; white-space: pre-wrap; word-break: break-word; }

.limit-list { margin: 0; padding: 0; list-style: none; display: grid; gap: 11px; }
.limit-list li { padding: 19px 22px; border: 1px solid var(--line); border-radius: 12px; background: var(--panel); display: grid; gap: 7px; }
.limit-list b { color: var(--echo-ink); font-size: 13.5px; font-weight: 460; }
.limit-list span { color: var(--muted); font-size: 12.5px; line-height: 1.72; }
.spec-links { margin-top: 30px; display: flex; flex-wrap: wrap; gap: 11px; }
.spec-link { padding: 11px 18px; display: inline-flex; align-items: center; gap: 9px; border: 1px solid var(--line-strong); border-radius: var(--echo-radius-sm); color: var(--echo-ink); font-size: 11px; letter-spacing: .08em; transition: border-color .2s ease, background .2s ease; }
.spec-link:hover { border-color: var(--cyan); background: rgba(9, 10, 12, .75); }

.dev-footer { padding: 44px 0 60px; display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 18px; }
.dev-footer nav { display: flex; flex-wrap: wrap; gap: 22px; }
.dev-footer a { color: var(--echo-ink-muted); font-size: 9px; letter-spacing: .14em; text-transform: uppercase; transition: color .2s ease; }
.dev-footer a:hover { color: var(--echo-ink); }
.dev-footer small { color: var(--echo-ink-faint); font-size: 9px; letter-spacing: .08em; }

@media (max-width: 900px) {
  .tier-grid { grid-template-columns: 1fr; }
  .hero-facts { gap: 10px; }
}

@media (max-width: 720px) {
  /* 导航在窄屏改为品牌 + 语言两栏，链接组降到第二行整宽横滑，
     避免三栏挤压把 44px 可点区压小。改动时同步 main 的 padding-top。 */
  /* height 必须放开：桌面固定 74px，换行成两排后会被第二排导航撑出去。 */
  .dev-header { grid-template-columns: auto auto; row-gap: 8px; height: auto; padding: 12px var(--gutter); }
  .dev-nav { grid-column: 1 / -1; order: 3; gap: 20px; overflow-x: auto; scrollbar-width: none; }
  .dev-nav::-webkit-scrollbar { display: none; }
  /* 两排表头的高度取决于导航行高，而导航行高只在 pointer: coarse 下才是 44px，
     所以窄屏细指针（缩窄的桌面窗口）与触摸屏要分别给值，否则一边会空出一截。 */
  main { padding-top: 100px; }
  .dev-section { scroll-margin-top: 100px; }
  /* 桌面的 168px 上留白叠在 main 的 128px 之上，窄屏会把首屏推空一大半。 */
  .dev-hero { padding-top: 34px; padding-bottom: 56px; }
  .dev-hero h1 { font-size: clamp(30px, 9vw, 44px); }
  .filter-row { flex-wrap: wrap; }
  #endpoint-filter { flex: 1 1 100%; }
  .play-controls { flex-direction: column; align-items: stretch; }
  .send-btn { width: 100%; }
  .dev-footer { flex-direction: column; align-items: flex-start; }
}

/* 触摸设备最小可点区域 44×44（WCAG 2.5.5），与首页同一策略：
   只在 pointer: coarse 下放大，桌面精确指针保持紧凑排版。 */
@media (pointer: coarse) {
  .locale-switch { gap: 0; }
  .locale-switch button { min-width: 44px; min-height: 44px; padding: 0; display: inline-flex; align-items: center; justify-content: center; }
  /* 2.5.5 要求 44×44，短标签（如「开始」）本身只有 20 余像素宽，需补最小宽度。 */
  .dev-nav a { min-width: 44px; min-height: 44px; display: inline-flex; align-items: center; justify-content: center; }
  .copy-btn, .send-btn, .spec-link, .back-echo { min-height: 44px; }
  .copy-btn { padding-left: 16px; padding-right: 16px; }
  #endpoint-filter, #play-endpoint { min-height: 44px; }
  .dev-footer nav { gap: 4px; }
  .dev-footer nav a { min-height: 44px; display: inline-flex; align-items: center; padding: 0 10px; }
}

/* 最窄的手机上让出产品名，保证「回到宇宙」和语言切换都留在首行。 */
@media (max-width: 359px) {
  .dev-brand .echo-lockup-product { display: none; }
}

@media (pointer: coarse) and (max-width: 720px) {
  main { padding-top: 128px; }
  .dev-section { scroll-margin-top: 128px; }
}

@media (prefers-reduced-motion: reduce) {
  * { animation-duration: .001ms !important; animation-iteration-count: 1 !important; transition-duration: .001ms !important; scroll-behavior: auto !important; }
}