/* Arspura AI 净烟机 · 内部评审演示
   Identity lives in the light: ice-white core, cyan above / magenta below, fading tails.
   Everything around it stays typographic and quiet. */

:root {
  --void: #000000;
  --title: #f2f2f2;
  --paper: #d4d4d4;
  --body: #b8b8b8;
  --mute: #7a7a7a;
  --dim: #5a5a5a;
  --line: #1e1e1e;
  --line-2: #2c2c2c;
  --ice: #f3f7ff;
  --cyan: #5cd6ff;
  --magenta: #fa287f;
  --amber: #c48a3a;
  --rose: #c46a6a;
  --nav-h: 56px;
  --content: 1160px;
  --pad: 48px;
  --font-cjk: "Noto Sans SC", "Noto Sans CJK SC", "Source Han Sans SC", "Mark Extra", "PingFang SC", "Microsoft YaHei", "Noto Sans", "Segoe UI Emoji", "Apple Color Emoji", "Noto Color Emoji", sans-serif;
  --font-latin: Outfit, "Noto Sans", sans-serif;
}

@font-face {
  font-family: Outfit;
  src: url("../assets/fonts/Outfit-Variable.ttf") format("truetype");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
  unicode-range: U+0000-00FF, U+0131, U+0152-0153, U+02BB-02BC, U+02C6, U+02DA, U+02DC, U+0304, U+0308, U+0329, U+2000-206F, U+2190-2193, U+2212, U+2215, U+FEFF, U+FFFD;
}

@font-face {
  font-family: "Noto Sans SC";
  src: url("../assets/fonts/NotoSansSC-Regular.woff") format("woff");
  font-weight: 400;
  font-style: normal;
  font-display: swap;
}

@font-face {
  font-family: "Noto Sans SC";
  src: url("../assets/fonts/NotoSansSC-Bold.woff") format("woff");
  font-weight: 700;
  font-style: normal;
  font-display: swap;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

@font-face {
  font-family: "Mark Extra";
  src: url("../assets/fonts/MarkExtra.woff") format("woff");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
  unicode-range: U+274C;
}

html {
  background: var(--void);
  color: var(--body);
  font-family: var(--font-cjk);
  font-weight: 400;
  line-height: 1.7;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
  color-scheme: dark;
}

body {
  margin: 0;
  background: var(--void);
  min-width: 320px;
}

img,
video {
  display: block;
  max-width: 100%;
  height: auto;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  padding: 0;
  cursor: pointer;
}

a {
  color: inherit;
  text-decoration: none;
}

:focus {
  outline: none;
}

:focus-visible {
  outline: 1px solid var(--cyan);
  outline-offset: 3px;
}

.latin {
  font-family: var(--font-latin);
}

/* ——— Nav ——— */

.site-nav {
  position: fixed;
  inset: 0 0 auto 0;
  z-index: 40;
  height: var(--nav-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 24px;
  padding: 0 var(--pad);
  background: rgba(0, 0, 0, 0.92);
  border-bottom: 1px solid var(--line);
}

.wordmark {
  font-family: var(--font-latin);
  font-weight: 400;
  font-size: 15px;
  letter-spacing: 0.02em;
  color: var(--title);
  flex: none;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 0;
  overflow-x: auto;
  scrollbar-width: none;
  min-width: 0;
}

.nav-links::-webkit-scrollbar {
  display: none;
}

.nav-links a {
  flex: none;
  padding: 8px 10px;
  font-size: 13px;
  color: var(--mute);
  white-space: nowrap;
}

.nav-links a:hover {
  color: var(--paper);
}

.nav-links a.is-current {
  color: var(--title);
}

/* ——— Layout ——— */

.wrap {
  width: min(100% - (var(--pad) * 2), var(--content));
  margin-inline: auto;
}

.section {
  padding: 96px 0 24px;
  scroll-margin-top: calc(var(--nav-h) + 8px);
}

.section-head {
  display: flex;
  align-items: baseline;
  gap: 14px;
  margin: 0 0 28px;
  padding-top: 22px;
  border-top: 1px solid var(--line);
}

.chap {
  font-size: 13px;
  color: var(--dim);
  flex: none;
  line-height: 1;
}

.h2 {
  margin: 0;
  font-size: 22px;
  font-weight: 400;
  color: var(--title);
  letter-spacing: 0.04em;
  line-height: 1.3;
}

.lead {
  max-width: 42em;
  margin: 0 0 32px;
  font-size: 15px;
  color: var(--paper);
  line-height: 1.75;
}

.lead em,
.lead strong {
  font-style: normal;
  font-weight: 700;
  color: var(--title);
}

.note {
  margin: 10px 0 0;
  font-size: 12px;
  color: var(--dim);
}

/* ——— Hero ——— */

.hero {
  min-height: 100dvh;
  padding: calc(var(--nav-h) + 12px) 0 56px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  scroll-margin-top: 0;
}

.hero-light {
  position: relative;
  width: min(94vw, 1400px);
  margin: 0 auto;
  aspect-ratio: 2.6 / 1;
  max-height: calc(100dvh - var(--nav-h) - 160px);
  background: #000;
}

.hero-light img,
.hero-light video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  background: #000;
}

.hero-light video {
  z-index: 1;
}

.hero-copy {
  width: min(92vw, 1320px);
  margin: 8px auto 0;
  text-align: center;
}

.hero-stance {
  margin: 0;
  font-size: 18px;
  font-weight: 400;
  color: var(--paper);
  letter-spacing: 0.08em;
  line-height: 1.7;
}

.hero-note {
  margin: 14px 0 0;
  font-size: 12px;
  color: var(--dim);
}

/* ——— Figures ——— */

.pair {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 2px;
  background: var(--void);
  margin: 0 0 8px;
}

.pair figure,
.plate figure {
  margin: 0;
}

.pair img,
.plate img {
  width: 100%;
  height: auto;
  background: #000;
}

.plate {
  margin: 0 0 36px;
}

.table-wrap + .plate {
  margin-top: 48px;
}

/* No stacked captions on figures — names only when needed, and short. */
.pair figcaption,
.plate figcaption {
  display: none;
}

/* ——— Quote & example ——— */

.quote {
  max-width: 44em;
  margin: 0 0 36px;
  padding: 0 0 0 18px;
  border-left: 1px solid var(--line-2);
  color: var(--paper);
  font-size: 15px;
  line-height: 1.75;
}

.quote strong {
  font-weight: 700;
  color: var(--title);
}

.example {
  margin: 0;
  max-width: 52em;
}

.example-lead {
  margin: 0 0 16px;
  color: var(--mute);
  font-size: 13px;
}

.example dl {
  margin: 0;
  display: grid;
  grid-template-columns: 5em 1fr;
  gap: 8px 20px;
  font-size: 14px;
  line-height: 1.65;
}

.example dt {
  color: var(--title);
  font-weight: 400;
}

.example dd {
  margin: 0;
  color: var(--paper);
}

.bridge {
  margin: 36px 0 0;
  max-width: 36em;
  font-size: 14px;
  color: var(--mute);
  line-height: 1.7;
}

/* ——— Tables ——— */

.table-wrap {
  overflow-x: auto;
  margin: 0 0 8px;
  -webkit-overflow-scrolling: touch;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 13px;
  line-height: 1.55;
}

th,
td {
  text-align: left;
  vertical-align: top;
  padding: 11px 14px 11px 0;
  border-bottom: 1px solid var(--line);
}

th {
  font-weight: 700;
  color: var(--title);
  border-bottom: 1px solid var(--line-2);
  white-space: nowrap;
}

td {
  color: var(--body);
}

td:first-child {
  color: var(--paper);
  padding-right: 20px;
}

.table-dense {
  font-size: 12.5px;
}

.table-dense th,
.table-dense td {
  padding: 10px 12px 10px 0;
}

tr.is-rejected td {
  color: var(--mute);
}

tr.is-rejected td:first-child {
  color: var(--body);
}

/* ——— Confirm sequence ——— */

.sequence {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px 40px;
  margin: 8px 0 0;
}

.step-num {
  font-family: var(--font-latin);
  font-weight: 300;
  font-size: 28px;
  color: var(--ice);
  letter-spacing: 0.02em;
  line-height: 1;
  margin: 0 0 14px;
}

.step h3 {
  margin: 0 0 10px;
  font-size: 17px;
  font-weight: 400;
  color: var(--title);
  letter-spacing: 0.06em;
}

.step p {
  margin: 0;
  font-size: 14px;
  color: var(--body);
  max-width: 28em;
  line-height: 1.7;
}

/* ——— Two tables in a section ——— */

.stack {
  display: flex;
  flex-direction: column;
  gap: 64px;
}

.subhead {
  margin: 0 0 18px;
  font-size: 16px;
  font-weight: 400;
  color: var(--title);
  letter-spacing: 0.06em;
}

.sub-lead {
  max-width: 42em;
  margin: -8px 0 22px;
  font-size: 14px;
  color: var(--body);
}

/* ——— Nine-state stage ——— */

.stage-section {
  padding: 80px 0 72px;
  scroll-margin-top: var(--nav-h);
}

.stage {
  width: min(100% - (var(--pad) * 2), 1280px);
  margin: 0 auto;
}

.stage-rail {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 2px 4px;
  margin: 0 0 8px;
}

.stage-rail button {
  padding: 8px 14px;
  font-size: 14px;
  color: var(--mute);
  letter-spacing: 0.08em;
  border-bottom: 1px solid transparent;
}

.stage-rail button:hover {
  color: var(--paper);
}

.stage-rail button.is-on {
  color: var(--ice);
  border-bottom-color: var(--ice);
}

.stage-frame {
  position: relative;
  width: 100%;
  aspect-ratio: 2.4 / 1;
  max-height: 58vh;
  margin: 0 auto;
  background: #000;
}

.stage-frame img,
.stage-frame video {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center;
  background: #000;
}

.stage-frame video {
  z-index: 1;
}

.stage-meta {
  text-align: center;
  margin: 18px auto 0;
  max-width: 36em;
}

.stage-name {
  margin: 0;
  font-size: 18px;
  font-weight: 400;
  color: var(--title);
  letter-spacing: 0.14em;
}

.stage-when {
  margin: 8px 0 0;
  font-size: 13px;
  color: var(--mute);
}

.stage-look {
  margin: 8px 0 0;
  font-size: 14px;
  color: var(--paper);
  line-height: 1.65;
}

.safety-toggle {
  display: none;
  justify-content: center;
  gap: 4px;
  margin: 14px 0 0;
}

.safety-toggle.is-visible {
  display: flex;
}

.safety-toggle button {
  padding: 4px 12px;
  font-size: 13px;
  color: var(--mute);
  letter-spacing: 0.1em;
  border-bottom: 1px solid transparent;
}

.safety-toggle button.is-on {
  color: var(--amber);
  border-bottom-color: var(--amber);
}

.safety-toggle button[data-grade="危"].is-on {
  color: var(--rose);
  border-bottom-color: var(--rose);
}

.kbd-hint {
  margin: 22px 0 0;
  text-align: center;
  font-size: 12px;
  color: var(--dim);
}

.original {
  width: min(100% - (var(--pad) * 2), var(--content));
  margin: 56px auto 0;
}

.original .h3 {
  margin: 0 0 8px;
  font-size: 15px;
  font-weight: 400;
  color: var(--paper);
}

.original .note {
  margin: 0 0 16px;
}

/* ——— Footer ——— */

.site-foot {
  padding: 48px 0 64px;
  border-top: 1px solid var(--line);
  margin-top: 64px;
}

.site-foot p {
  margin: 0;
  font-size: 12px;
  color: var(--dim);
  max-width: 44em;
  line-height: 1.7;
}

/* ——— Reduced motion ——— */

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .hero-light video,
  .stage-frame video {
    display: none;
  }
}

/* ——— Short laptop height ——— */

@media (max-height: 820px) {
  .hero {
    padding-bottom: 28px;
  }

  .hero-light {
    max-height: calc(100dvh - var(--nav-h) - 130px);
  }

  .hero-stance {
    font-size: 16px;
    letter-spacing: 0.06em;
  }

  .stage-frame {
    max-height: 52vh;
  }
}

/* ——— Narrower windows ——— */

@media (max-width: 1100px) {
  :root {
    --pad: 32px;
  }

  .sequence {
    gap: 28px 24px;
  }

  .nav-links a {
    padding: 8px 8px;
    font-size: 12px;
  }
}

@media (max-width: 860px) {
  :root {
    --pad: 20px;
    --nav-h: 52px;
  }

  .pair,
  .sequence {
    grid-template-columns: 1fr;
    gap: 16px;
  }

  .section {
    padding-top: 72px;
  }

  .h2 {
    font-size: 20px;
  }

  .example dl {
    grid-template-columns: 1fr;
    gap: 2px 0;
  }

  .example dt {
    margin-top: 10px;
  }

  .hero-stance {
    font-size: 15px;
    letter-spacing: 0.04em;
  }

  td:first-child {
    white-space: nowrap;
  }

  .table-dense td:first-child {
    white-space: normal;
  }
}