/* ==========================================================================
   会话互通 · Onethread — 第六版：浅色太阳系
   扁平、复杂、抽象。纸色底，墨色细线，一根金线，一点赭红与蓝。只有浅色一套。
   首幕由 sky.js 画在 canvas 上；各节的小画布由 scenes.js、演示窗口由 demo.js 画，画法共用 orbitkit.js。
   ========================================================================== */

:root {
  --bg: #f1ecdf;
  --bg-2: #ebe5d6;
  --bg-3: #e3dccb;
  --paper: #f3eee2;
  --ink: #1a1b22;
  --ink-2: #4a4a52;
  --muted: #7b776c;
  --line: rgba(26, 27, 34, .12);
  --line-2: rgba(26, 27, 34, .26);
  --gold: #a9822d;
  --gold-hi: #c9a24a;
  --gold-soft: rgba(169, 130, 45, .12);
  --red: #b8341f;
  --blue: #2f5f9e;
  --claude: #b8552f;
  --codex: #2f5f9e;
  --gray: #9a958a;
  --art-line: rgba(26, 27, 34, .6);
  --art-faint: rgba(26, 27, 34, .22);
  --serif-zh: "Noto Serif SC", "Songti SC", "SimSun", serif;
  --serif-en: "Cormorant Garamond", "Noto Serif SC", Georgia, serif;
  --mono: "JetBrains Mono", Consolas, monospace;
  --max: 1180px;
  --gutter: clamp(18px, 5vw, 64px);
  --section-y: clamp(96px, 13vw, 170px);
  --ease: cubic-bezier(.22, .68, .18, 1);
  color-scheme: light;
}

/* ---------- 基础 ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; -webkit-text-size-adjust: 100%; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } }
body { margin: 0; background: var(--bg); color: var(--ink); font-family: var(--serif-zh); font-weight: 300; font-size: 16px; line-height: 1.95; letter-spacing: .02em; -webkit-font-smoothing: antialiased; overflow-x: hidden; }
html[data-lang="en"] body { font-family: var(--serif-en); font-weight: 400; font-size: 18px; line-height: 1.7; letter-spacing: .005em; }
.wall-tex, .vignette { display: none; }
h1, h2, h3 { margin: 0; font-weight: 400; }
p { margin: 0; }
a { color: inherit; text-decoration: none; }
button { font: inherit; color: inherit; }
svg { display: block; }
strong, b { font-weight: 700; }
::selection { background: var(--gold); color: var(--paper); }
html[data-lang="zh"] .en { display: none !important; }
html[data-lang="en"] .zh { display: none !important; }
html[data-lang] .bi > .zh, html[data-lang] .bi > .en, html[data-lang] .bi-h3 > .zh, html[data-lang] .bi-h3 > .en { display: block !important; }
.skip { position: absolute; left: 16px; top: -60px; z-index: 100; padding: 8px 12px; background: var(--gold); color: var(--paper); }
.skip:focus { top: 12px; }
.caps { font-family: var(--serif-en); font-variant: small-caps; letter-spacing: .28em; }

/* ---------- 导航 ---------- */
.nav { position: fixed; top: 0; left: 0; right: 0; z-index: 50; display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 16px; padding: 16px var(--gutter); background: transparent; transition: background .4s; }
body.past-hero .nav, .nav.open { background: color-mix(in srgb, var(--bg) 88%, transparent); -webkit-backdrop-filter: blur(12px); backdrop-filter: blur(12px); }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--ink); }
.mark { width: 22px; height: 22px; color: var(--ink); }
.mark.big { width: 56px; height: 56px; }
.brand-zh { font-weight: 700; font-size: 16px; letter-spacing: .14em; }
.brand-en { font-family: var(--serif-en); font-style: italic; font-size: 16px; color: var(--gold); }
html[data-lang="en"] .brand-zh { font-size: 12.5px; font-weight: 400; order: 2; color: var(--muted); letter-spacing: .3em; }
html[data-lang="en"] .brand-en { font-style: normal; font-size: 18px; color: var(--ink); letter-spacing: .06em; }
.nav-links { display: flex; gap: 30px; justify-self: center; }
.nav-links a { font-size: 13px; color: var(--ink-2); letter-spacing: .2em; position: relative; padding: 4px 0; }
html[data-lang="en"] .nav-links a { font-family: var(--serif-en); font-variant: small-caps; font-size: 16px; letter-spacing: .2em; }
.nav-links a::after { content: ""; position: absolute; left: 50%; right: 50%; bottom: -2px; height: 1px; background: var(--gold); transition: left .35s var(--ease), right .35s var(--ease); }
.nav-links a:hover::after, .nav-links a:focus-visible::after { left: 0; right: 0; }
.nav-links .nav-cta { color: var(--gold); }
.nav-tools { display: flex; gap: 8px; justify-self: end; align-items: center; }
.menu-toggle, .lang-toggle { height: 32px; border-radius: 999px; border: 1px solid var(--line-2); background: transparent; cursor: pointer; display: inline-flex; align-items: center; justify-content: center; transition: border-color .3s, color .3s; }
.menu-toggle { width: 32px; }
.lang-toggle { padding: 0 12px; gap: 6px; font-family: var(--serif-en); font-size: 13px; letter-spacing: .08em; color: var(--muted); }
.lang-toggle .lt-sep { opacity: .5; }
.lang-toggle .lt-zh { font-family: var(--serif-zh); font-weight: 400; }
html[data-lang="zh"] .lang-toggle .lt-zh, html[data-lang="en"] .lang-toggle .lt-en { color: var(--gold); }
.menu-toggle:hover, .lang-toggle:hover { border-color: var(--gold); color: var(--gold); }
.menu-toggle { display: none; flex-direction: column; gap: 5px; }
.menu-toggle span { width: 15px; height: 1px; background: var(--ink); transition: transform .3s var(--ease); }
.menu-toggle[aria-expanded="true"] span:first-child { transform: translateY(3px) rotate(45deg); }
.menu-toggle[aria-expanded="true"] span:last-child { transform: translateY(-3px) rotate(-45deg); }
.mobile-menu { display: none; grid-column: 1 / -1; flex-direction: column; padding: 10px 0 8px; border-top: 1px solid var(--line); }
.mobile-menu a { display: flex; gap: 14px; align-items: baseline; padding: 12px 2px; border-bottom: 1px solid var(--line); font-size: 16px; }
.mobile-menu a i { font-family: var(--serif-en); font-style: normal; color: var(--gold); width: 28px; font-size: 14px; }
.mobile-menu a:last-child { border-bottom: 0; }
.nav.open .mobile-menu { display: flex; }

/* ---------- 共用 ---------- */
.section { max-width: var(--max); margin: 0 auto; padding: clamp(48px, 7vw, 96px) var(--gutter); scroll-margin-top: 70px; }
.sec-head { max-width: 700px; margin-bottom: clamp(36px, 5vw, 60px); }
.sec-num { display: flex; align-items: baseline; gap: 16px; margin-bottom: 14px; color: var(--gold); }
.sec-num .roman { font-family: var(--serif-en); font-weight: 300; font-size: clamp(44px, 5vw, 64px); line-height: 1; letter-spacing: .06em; }
.sec-num::after { content: ""; flex: 0 0 72px; height: 1px; background: var(--line-2); align-self: center; }
h2.bi { display: flex; flex-direction: column; gap: 6px; }
h2.bi .zh { font-weight: 300; font-size: clamp(28px, 3.6vw, 40px); line-height: 1.4; letter-spacing: .08em; }
h2.bi .en { font-family: var(--serif-en); font-style: italic; font-weight: 300; font-size: clamp(19px, 2.2vw, 24px); color: var(--gold); line-height: 1.3; }
html[data-lang="en"] h2.bi .en { order: -1; font-style: normal; font-weight: 300; font-size: clamp(34px, 4.4vw, 54px); color: var(--ink); line-height: 1.1; letter-spacing: .01em; }
html[data-lang="en"] h2.bi .zh { font-size: 13px; color: var(--muted); letter-spacing: .4em; }
.sec-sub { margin-top: 14px; color: var(--muted); max-width: 44em; }
.bi-h3 { display: flex; flex-direction: column; gap: 2px; }
.bi-h3 .zh { font-weight: 700; font-size: 19px; line-height: 1.5; letter-spacing: .06em; }
.bi-h3 .en { font-family: var(--serif-en); font-style: italic; font-weight: 400; font-size: 16px; color: var(--gold); }
html[data-lang="en"] .bi-h3 .en { order: -1; font-style: normal; font-weight: 500; font-size: 22px; color: var(--ink); line-height: 1.25; }
html[data-lang="en"] .bi-h3 .zh { font-size: 12px; font-weight: 400; color: var(--muted); letter-spacing: .4em; }

.btn { display: inline-flex; align-items: center; gap: 10px; padding: 12px 26px; border-radius: 0; font-size: 14px; letter-spacing: .2em; border: 1px solid var(--line-2); cursor: pointer; white-space: nowrap; transition: transform .25s var(--ease), border-color .25s, color .25s, background .25s; }
html[data-lang="en"] .btn { font-family: var(--serif-en); font-variant: small-caps; font-size: 17px; letter-spacing: .2em; padding: 10px 26px; }
.btn:active { transform: translateY(1px); }
.btn-gold { background: var(--gold); color: var(--paper); border-color: var(--gold); }
.btn-gold:hover { background: transparent; color: var(--gold); }
.btn-line { color: var(--ink); }
.btn-line:hover { border-color: var(--gold); color: var(--gold); }
.btn .arr { font-style: normal; font-family: var(--serif-en); transition: transform .3s var(--ease); }
.btn-line:hover .arr { transform: translateX(4px); }
.actions { display: flex; flex-wrap: wrap; gap: 12px; align-items: center; margin-top: 32px; }
.actions.centered { justify-content: center; margin-top: clamp(28px, 4vw, 40px); }
.note { font-family: var(--serif-en); font-style: italic; font-size: 15px; color: var(--muted); }
.reveal { opacity: 0; transform: translateY(18px); transition: opacity 1s var(--ease), transform 1s var(--ease); }
.reveal.in { opacity: 1; transform: none; }
@media (prefers-reduced-motion: reduce) { .reveal { opacity: 1; transform: none; transition: none; } }

/* ---------- 首幕：太阳系。画布铺满视口，标题、小字、按钮浮在画布上 ---------- */
.hero { position: relative; height: 100vh; height: 100svh; min-height: 540px; overflow: hidden; }
.sky { position: absolute; inset: 0; }
.sky canvas { display: block; width: 100%; height: 100%; }
.hero-top { position: absolute; left: 0; right: 0; top: clamp(72px, 9vh, 120px); padding: 0 var(--gutter); text-align: center; z-index: 2; pointer-events: none; }
.hero-top > * { pointer-events: auto; }
.display.compact { max-width: 1060px; margin: 0 auto; }
.display.compact .zh { display: block; font-weight: 300; font-size: clamp(21px, 2.4vw, 32px); line-height: 1.5; letter-spacing: .08em; }
.display.compact .en { display: block; font-family: var(--serif-en); font-weight: 300; font-size: clamp(25px, 2.6vw, 36px); line-height: 1.12; }
.display em { font-style: normal; color: var(--gold); font-weight: 700; }
.display .en em { font-style: italic; font-weight: 400; }
.hero-bottom { position: absolute; left: 0; right: 0; bottom: 6vh; z-index: 2; margin: 0; padding: 0 var(--gutter); justify-content: center; }



/* ---------- 首屏之后：背景星尘、节标题、节间弧线 ---------- */
.bg-dust { position: fixed; inset: 0; width: 100%; height: 100%; z-index: -1; pointer-events: none; opacity: 0; }
.sec-title { font-weight: 300; font-size: clamp(28px, 3.4vw, 40px); line-height: 1.35; letter-spacing: .08em; }
html[data-lang="en"] .sec-title { font-family: var(--serif-en); font-size: clamp(32px, 4vw, 48px); line-height: 1.1; letter-spacing: .01em; }
html[data-lang="en"] .sec-sub { font-family: var(--serif-en); font-style: italic; font-size: 19px; }
.arc { position: relative; max-width: var(--max); margin: 0 auto; padding: 0 var(--gutter); }
.arc svg { display: block; width: 100%; height: 40px; overflow: visible; clip-path: inset(0 100% 0 0); transition: clip-path 2.4s var(--ease) .15s; }
.arc.in svg { clip-path: inset(0 0 0 0); }
.arc path { fill: none; stroke: var(--gold); stroke-opacity: .5; stroke-width: 1; vector-effect: non-scaling-stroke; }
.arc i { position: absolute; left: 50%; top: 11px; width: 5px; height: 5px; margin-left: -2.5px; border-radius: 50%; background: var(--gold); opacity: 0; transition: opacity .8s 1.8s; }
.arc.in i { opacity: .75; }
@media (prefers-reduced-motion: reduce) { .arc svg { clip-path: none; transition: none; } .arc i { opacity: .75; transition: none; } }

/* §1 §2：三格小画布 */
.cells { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: clamp(16px, 2.4vw, 32px); }
.cell { margin: 0; }
.cell:nth-child(2) { transition-delay: .12s; } .cell:nth-child(3) { transition-delay: .24s; }
.cell canvas { display: block; width: 100%; aspect-ratio: 360 / 260; -webkit-mask-image: radial-gradient(ellipse 72% 70% at 50% 50%, #000 62%, transparent 100%); mask-image: radial-gradient(ellipse 72% 70% at 50% 50%, #000 62%, transparent 100%); }
.cell figcaption { margin-top: 8px; padding-top: 10px; border-top: 1px solid var(--line); }
.cell-cap { font-size: 15px; line-height: 1.75; color: var(--ink); }
.cell-fix { margin-top: 6px; font-size: 14px; line-height: 1.7; color: var(--gold); }
html[data-lang="en"] .cell-cap { font-family: var(--serif-en); font-size: 17.5px; line-height: 1.45; }
html[data-lang="en"] .cell-fix { font-family: var(--serif-en); font-style: italic; font-size: 16.5px; line-height: 1.45; }
.tags { display: flex; flex-wrap: wrap; gap: 10px; margin-top: clamp(28px, 4vw, 44px); }
.tag { padding: 6px 15px; border: 1px solid var(--line-2); border-radius: 999px; background: transparent; color: var(--ink-2); font-size: 13.5px; letter-spacing: .08em; cursor: pointer; transition: border-color .25s, color .25s, background .25s; }
html[data-lang="en"] .tag { font-family: var(--serif-en); font-size: 16px; letter-spacing: .02em; }
.tag:hover, .tag:focus-visible, .tag[aria-expanded="true"] { border-color: var(--gold); color: var(--gold); outline: none; }
.tag[aria-expanded="true"] { background: var(--gold-soft); }
.tag-note { margin-top: 16px; max-width: 40em; padding-left: 14px; border-left: 1px solid var(--gold); color: var(--ink-2); font-size: 15.5px; }
html[data-lang="en"] .tag-note { font-family: var(--serif-en); font-size: 18px; line-height: 1.5; }
.tag-note[hidden], .tag-text[hidden] { display: none; }

/* §3：画出来的桌面程序 */
.demo { position: relative; max-width: 880px; margin: 0 auto; }
.dwin { border: 1px solid rgba(26, 27, 34, .5); border-radius: 10px; background: var(--paper); overflow: hidden; }
.dbar { display: flex; gap: 6px; padding: 10px 12px; border-bottom: 1px solid var(--line); }
.dbar i { width: 9px; height: 9px; border: 1px solid var(--line-2); border-radius: 50%; }
.dbody { position: relative; min-height: 470px; padding: 18px 22px 22px; overflow: hidden; transition: opacity .5s; }
html[data-lang="en"] .dbody { font-family: var(--serif-en); }
.dhd { display: flex; align-items: baseline; flex-wrap: wrap; gap: 4px 12px; margin-bottom: 10px; }
.dhd b { font-size: 18px; font-weight: 700; letter-spacing: .06em; }
.dd { font-size: 12.5px; color: var(--muted); }
.dr { display: grid; grid-template-columns: 20px minmax(0, 1fr) 84px 196px; gap: 10px; align-items: center; padding: 9px 6px; border-bottom: 1px solid var(--line); font-size: 13.5px; line-height: 1.5; transition: background .35s; }
html[data-lang="en"] .dr { font-size: 15px; }
.dth { padding-top: 4px; font-size: 12px; letter-spacing: .14em; color: var(--muted); }
html[data-lang="en"] .dth { font-size: 13px; font-variant: small-caps; }
.dth span:last-child, .ds { justify-self: end; text-align: right; }
.ck i { position: relative; display: block; width: 13px; height: 13px; border: 1px solid var(--line-2); border-radius: 3px; transition: background .25s, border-color .25s; }
.demo.checked .dr[data-row="1"] { background: var(--gold-soft); }
.demo.checked .dr[data-row="1"] .ck i { background: var(--gold); border-color: var(--gold); }
.demo.checked .dr[data-row="1"] .ck i::after { content: ""; position: absolute; left: 3.6px; top: 1px; width: 3.5px; height: 7px; border: solid var(--paper); border-width: 0 1.5px 1.5px 0; transform: rotate(45deg); }
.dt { display: flex; gap: 8px; align-items: flex-start; min-width: 0; }
.dtt { min-width: 0; }
.tm { flex: none; width: 8px; height: 8px; margin-top: .55em; border-radius: 50%; }
.tm.claude { background: var(--claude); } .tm.codex { background: var(--codex); }
.tm-svg { flex: none; display: block; width: 12px; height: 12px; margin-top: .32em; }
.dc-opt .tm-svg, .dc-opt .tm { margin-top: 0; }
.du { font-size: 12.5px; color: var(--muted); }
.st { display: inline-flex; align-items: center; gap: 5px; font-size: 12.5px; color: var(--muted); white-space: nowrap; }
.st.ok { color: var(--ink-2); }
.st b { font-weight: 400; }
.okk { width: 11px; height: 11px; fill: none; stroke: var(--gold); stroke-width: 1.6; stroke-linecap: round; stroke-linejoin: round; }
.t-claude { color: var(--claude); } .t-codex { color: var(--codex); }
.s-after, .dsub { display: none; }
.demo[data-s="3"] .s-before { display: none; }
.demo[data-s="3"] .s-after { display: inline; }
.demo[data-s="3"] .dsub { display: block; }
.dsub { margin-top: 2px; font-size: 11.5px; color: var(--muted); }
.dcard { position: absolute; top: 58px; right: 18px; width: min(54%, 440px); padding: 16px 18px; border: 1px solid rgba(26, 27, 34, .45); border-radius: 8px; background: var(--paper); box-shadow: -24px 0 40px -34px rgba(26, 27, 34, .45); opacity: 0; visibility: hidden; transform: translateX(calc(100% + 40px)); transition: transform .7s var(--ease), opacity .5s, visibility 0s linear .7s; }
.demo[data-s="2"] .dcard, .demo[data-s="3"] .dcard { opacity: 1; visibility: visible; transform: none; transition: transform .7s var(--ease), opacity .5s; }
.demo.fade .dcard { opacity: 0; }
.dc-ft { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); gap: 10px; align-items: start; }
.dc-cap { margin-bottom: 8px; font-size: 11.5px; letter-spacing: .14em; color: var(--muted); }
html[data-lang="en"] .dc-cap { font-size: 13px; font-variant: small-caps; }
.dc-src { display: flex; gap: 8px; align-items: flex-start; }
.dc-src b { display: block; font-size: 14px; font-weight: 400; }
.dc-src small, .dc-opt small { display: block; font-size: 11px; color: var(--muted); }
.dc-arrow { padding-top: 22px; color: var(--gold); font-family: var(--serif-en); }
.dc-opt { display: flex; flex-wrap: wrap; align-items: center; gap: 0 8px; margin-bottom: 6px; font-size: 13.5px; }
.dc-opt b { font-weight: 400; }
.dc-opt .bx { display: inline-flex; align-items: center; justify-content: center; width: 13px; height: 13px; border: 1px solid var(--gold); border-radius: 3px; background: var(--gold); }
.dc-opt .bx .okk { width: 10px; height: 10px; stroke: var(--paper); }
.dc-opt.off { opacity: .55; }
.dc-opt.off .bx { border-color: var(--line-2); background: transparent; }
.dc-opt small { width: 100%; padding-left: 21px; }
.dc-land { display: flex; justify-content: space-between; align-items: center; gap: 10px; margin-top: 12px; padding-top: 10px; border-top: 1px solid var(--line); }
.dc-land .dc-cap { margin: 0; }
.dc-sel { padding: 2px 10px; border: 1px solid var(--line-2); border-radius: 4px; font-size: 12.5px; }
.dc-act { margin-top: 14px; }
.dc-go { display: block; padding: 8px 0; border-radius: 4px; background: var(--gold); color: var(--paper); font-size: 14px; letter-spacing: .14em; text-align: center; transition: filter .2s, transform .2s; }
.demo.press .dc-go { filter: brightness(.88); transform: translateY(1px); }
.dc-prog { display: block; height: 1px; margin-top: 8px; background: var(--line); }
.dc-prog i { display: block; width: 0; height: 100%; background: var(--gold); }
.demo.run .dc-prog i { width: 100%; transition: width 1.8s linear; }
.dc-next { display: none; }
.demo[data-s="3"] .dc-sync { display: none; }
.demo[data-s="3"] .dc-next { display: block; }
.demo[data-s="3"] .dcard { top: auto; bottom: 16px; }
.dc-h { margin-bottom: 8px; font-size: 14.5px; font-weight: 700; }
.dc-line { display: flex; gap: 8px; font-size: 13.5px; line-height: 1.7; color: var(--ink-2); }
.dcur { position: absolute; left: 0; top: 0; z-index: 3; width: 15px; height: 21px; fill: var(--paper); stroke: var(--ink); stroke-width: 1; stroke-linejoin: round; pointer-events: none; }
.dclick { position: absolute; z-index: 2; width: 24px; height: 24px; margin: -12px 0 0 -12px; border: 1px solid var(--gold); border-radius: 50%; opacity: 0; pointer-events: none; }
.dclick.on { animation: dclick .55s ease-out; }
@keyframes dclick { from { transform: scale(.3); opacity: .9; } to { transform: scale(1.5); opacity: 0; } }

/* §4：范围、三步、问答，纯文字，大一档 */
.more .scope { display: grid; grid-template-columns: 1fr 1fr; gap: clamp(28px, 5vw, 72px); }
.scope-title { display: flex; align-items: center; gap: 12px; margin-bottom: 14px; font-size: 20px; font-weight: 700; letter-spacing: .1em; }
html[data-lang="en"] .scope-title { font-family: var(--serif-en); font-variant: small-caps; font-size: 23px; font-weight: 500; letter-spacing: .2em; }
.seal-dot { width: 10px; height: 10px; border-radius: 50%; }
.seal-dot.in { background: var(--gold); }
.seal-dot.out { border: 1px solid var(--line-2); }
.scope-list { list-style: none; margin: 0; padding: 0; border-top: 1px solid var(--line-2); }
.scope-list li { display: grid; grid-template-columns: 8.5em 1fr; gap: 12px; padding: 13px 0; border-bottom: 1px solid var(--line); font-size: 16.5px; }
html[data-lang="en"] .scope-list li { grid-template-columns: 11em 1fr; font-size: 18.5px; }
.scope-list b { font-weight: 400; }
.scope-list span { color: var(--ink-2); }
.scope-list.muted b { color: var(--ink-2); }
.steps { list-style: none; display: grid; grid-template-columns: repeat(3, 1fr); gap: clamp(20px, 3vw, 40px); margin: clamp(48px, 6vw, 72px) 0 0; padding: 0; }
.steps li { position: relative; padding-top: 18px; border-top: 1px solid var(--line-2); }
.steps li::before { content: ""; position: absolute; left: 0; top: -1px; width: 44px; height: 1px; background: var(--gold); }
.step-num { display: block; margin-bottom: 10px; font-family: var(--serif-en); font-weight: 300; font-size: 48px; line-height: 1; letter-spacing: .06em; color: var(--gold); }
.step-t { font-size: 19px; letter-spacing: .06em; }
html[data-lang="en"] .step-t { font-family: var(--serif-en); font-size: 22px; letter-spacing: .01em; }

.faq { max-width: 860px; margin-top: clamp(48px, 6vw, 72px); border-top: 1px solid var(--line-2); }
.faq details { border-bottom: 1px solid var(--line); }
.faq summary { position: relative; padding: 20px 48px 20px 0; list-style: none; cursor: pointer; font-size: 19px; line-height: 1.5; letter-spacing: .04em; transition: color .25s; }
html[data-lang="en"] .faq summary { font-family: var(--serif-en); font-size: 23px; letter-spacing: 0; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: ""; position: absolute; right: 8px; top: 50%; width: 14px; height: 14px; margin-top: -7px; background: linear-gradient(var(--gold), var(--gold)) center / 14px 1px no-repeat, linear-gradient(var(--gold), var(--gold)) center / 1px 14px no-repeat; transition: transform .45s var(--ease); }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq summary:hover { color: var(--gold); }
.faq-body { max-width: 44em; padding: 0 0 24px; color: var(--ink-2); font-size: 16.5px; line-height: 1.9; }
html[data-lang="en"] .faq-body { font-family: var(--serif-en); font-size: 19px; line-height: 1.55; }

.get-frame { padding: clamp(32px, 5vw, 72px) 0; }
.get-title { margin-top: 4px; }
.get-grid { display: grid; grid-template-columns: 1.1fr 1fr; gap: clamp(32px, 6vw, 96px); align-items: center; }
.notify { display: grid; gap: 10px; }
.notify-label { font-weight: 700; font-size: 17px; letter-spacing: .06em; }
html[data-lang="en"] .notify-label { font-family: var(--serif-en); font-weight: 400; font-size: 22px; font-style: italic; }
.notify-row { display: flex; gap: 10px; }
.notify input { flex: 1; min-width: 0; padding: 12px 16px; border-radius: 0; border: 1px solid var(--line-2); background: var(--bg); color: var(--ink); font: inherit; font-size: 15px; outline: none; transition: border-color .25s, box-shadow .25s; }
.notify input::placeholder { color: var(--muted); }
.notify input:focus { border-color: var(--gold); box-shadow: 0 0 0 4px var(--gold-soft); }
.notify.invalid input { border-color: var(--red); box-shadow: 0 0 0 4px rgba(200,64,42,.18); }
.notify.invalid .hint { color: var(--red); }
.hint { font-size: 12.5px; color: var(--muted); letter-spacing: .04em; }
html[data-lang="en"] .hint { font-size: 14.5px; font-style: italic; }
.notify-done { display: flex; align-items: center; gap: 10px; padding: 12px 0; }
.notify-done[hidden] { display: none; }
.notify-done svg { width: 22px; height: 22px; color: var(--gold); flex: none; }
.notify-done b { font-weight: 700; color: var(--gold); }
.notify.done .notify-row, .notify.done .hint { display: none; }

.footer { margin-top: var(--section-y); border-top: 1px solid var(--line); }
.footer-inner { max-width: var(--max); margin: 0 auto; padding: 44px var(--gutter) 64px; display: grid; grid-template-columns: auto 1fr auto; gap: 28px; align-items: start; font-size: 13px; color: var(--muted); }
.footer-seal { width: 56px; height: 56px; color: var(--ink-2); }
.footer-brand { display: flex; flex-direction: column; gap: 2px; color: var(--ink); margin-bottom: 8px; }
.footer-legal { max-width: 50em; }
html[data-lang="en"] .footer-legal { font-size: 15px; font-style: italic; }
.footer-copy { font-family: var(--serif-en); letter-spacing: .2em; }

/* ---------- 响应式 ---------- */
@media (max-width: 900px) {
  .cells { grid-template-columns: 1fr; max-width: 480px; margin: 0 auto; gap: 28px; }
  .footer-inner { grid-template-columns: auto 1fr; } .footer-copy { grid-column: 2; }
}
@media (max-width: 820px) {
  .nav { grid-template-columns: 1fr auto; } .nav-links { display: none; } .menu-toggle { display: flex; }
  .get-grid { grid-template-columns: 1fr; }
  .more .scope { grid-template-columns: 1fr; }
  .steps { grid-template-columns: 1fr; }
}
@media (max-width: 719px) {
  .dbody { min-height: 520px; padding: 14px 12px 16px; }
  .dhd b { font-size: 16px; }
  .dr { grid-template-columns: 16px minmax(0, 1fr) 50px 96px; gap: 6px; padding: 8px 2px; font-size: 12px; }
  .st { white-space: normal; justify-content: flex-end; }
  .s-after .st { display: inline; }
  .dr .okk { display: none; }
  html[data-lang="en"] .dr { font-size: 13px; }
  .dd, .du, .st, .dth, .dsub, .dc-cap, .dc-src small, .dc-opt small, .dc-sel { font-size: 11px; }
  .dcard { top: auto; left: 10px; right: 10px; bottom: 10px; width: auto; padding: 12px 14px; transform: translateY(calc(100% + 30px)); box-shadow: 0 -20px 40px -30px rgba(26, 27, 34, .45); }
  .dc-ft { grid-template-columns: minmax(0, 1fr) minmax(0, 1fr); }
  .dc-arrow { display: none; }
  .dc-opt, .dc-line, .dc-src b { font-size: 12.5px; }
  .dc-go { padding: 6px 0; font-size: 13px; }
}
@media (max-width: 560px) {
  body { font-size: 15px; } html[data-lang="en"] body { font-size: 17px; }
  .brand-en { display: none; } html[data-lang="en"] .brand-en { display: inline; } html[data-lang="en"] .brand-zh { display: none; }
  .lang-toggle { padding: 0 9px; }
  .scope-list li, html[data-lang="en"] .scope-list li { grid-template-columns: 1fr; gap: 2px; }
  .actions .btn { flex: 1 1 auto; justify-content: center; }
  .hero-top { top: clamp(68px, 9vh, 100px); }
  .hero-bottom { bottom: 6vh; flex-direction: column; align-items: stretch; gap: 10px; }
  .sec-num .roman { font-size: 40px; }
  .faq summary { font-size: 17.5px; } html[data-lang="en"] .faq summary { font-size: 21px; }
}

/* 账号入口 */
.nav-links .nav-account { border-left: 1px solid var(--line-2); padding-left: 22px; }
.get-account { margin-top: 18px; font-size: 13.5px; color: var(--muted); }
.get-account a { color: var(--gold); border-bottom: 1px solid var(--gold-soft); }
.brand-zh, .brand-en { white-space: nowrap; }