/* Landing page and text pages (About, Privacy, 404).
   Colors, radii, shadow and fonts come only from tokens.css. The game styles itself (game.css). */

:root {
  color-scheme: light;
  --gutter: 16px;
  --page: 960px;
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-padding-top: 16px;
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

body {
  margin: 0;
  background: var(--c-bg);
  color: var(--c-text);
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-wrap: break-word;
}

:where(a, button, summary):focus-visible {
  outline: 3px solid var(--c-primary);
  outline-offset: 2px;
  border-radius: 6px;
}

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

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

.skip-link {
  position: absolute;
  top: 8px;
  left: 8px;
  z-index: 100;
  padding: 10px 16px;
  border-radius: var(--radius-sm);
  background: var(--c-primary);
  color: var(--c-card);
  font-weight: 600;
  text-decoration: none;
  transform: translateY(-160%);
  transition: transform 0.2s ease;
}

.skip-link:focus {
  transform: none;
}

/* ---------- Header ---------- */

.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  min-height: 64px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--c-text);
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1;
  text-decoration: none;
  white-space: nowrap;
}

.brand img {
  flex: none;
  width: 28px;
  height: 28px;
}

.site-nav ul {
  display: flex;
  gap: 4px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-nav a {
  display: block;
  padding: 8px 12px;
  border-radius: 999px;
  color: var(--c-text);
  font-size: 0.9375rem;
  font-weight: 500;
  line-height: 1.25;
  text-decoration: none;
  white-space: nowrap;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.site-nav a:hover {
  background: var(--c-primary-50);
  color: var(--c-primary-600);
}

/* ---------- Hero + game ---------- */

.hero {
  padding-block: 12px 24px;
  text-align: center;
}

.hero h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 1.9rem + 2.6vw, 3.5rem);
  font-weight: 700;
  line-height: 1.05;
  letter-spacing: -0.01em;
}

.hero h1 .accent {
  color: var(--c-primary);
}

.hero-sub {
  max-width: 52rem;
  margin: 10px auto 0;
  font-size: clamp(1.0625rem, 1rem + 0.3vw, 1.1875rem);
  line-height: 1.5;
  text-wrap: balance;
}

.play {
  padding-inline: var(--gutter);
}

.gts-mount {
  max-width: 960px;
  min-height: 560px;
  margin-inline: auto;
}

.noscript {
  max-width: 960px;
  margin: 0 auto;
  padding: 32px 24px;
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-card);
  font-size: 1.0625rem;
  text-align: center;
}

/* ---------- Content sections ---------- */

.section {
  margin-block: 88px;
}

.section h2 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 1.45rem + 1.3vw, 2.25rem);
  font-weight: 600;
  line-height: 1.15;
  letter-spacing: -0.01em;
}

.lead {
  max-width: 40rem;
  margin: 8px 0 0;
  font-size: 1.0625rem;
}

.card {
  border: 1px solid var(--c-border);
  border-radius: var(--radius);
  background: var(--c-card);
  box-shadow: var(--shadow);
}

.grid {
  display: grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 16px;
  margin: 28px 0 0;
  padding: 0;
  list-style: none;
}

@media (min-width: 720px) {
  .grid {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.step h3,
.mode h3,
.fact h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.25;
}

/* How to play */

.step {
  padding: 24px;
}

.step-num {
  display: grid;
  place-items: center;
  width: 40px;
  height: 40px;
  margin-bottom: 16px;
  border-radius: 50%;
  background: var(--c-primary-50);
  color: var(--c-primary-600);
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1;
}

.step p {
  margin: 6px 0 0;
}

/* Modes */

.mode {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 24px;
}

.mode-head {
  display: flex;
  align-items: center;
  gap: 12px;
}

.icon-tile {
  display: grid;
  flex: none;
  place-items: center;
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--c-primary-50);
  color: var(--c-primary);
}

.icon-tile svg {
  width: 24px;
  height: 24px;
}

.mode p {
  margin: 0;
}

.stats {
  display: flex;
  gap: 28px;
  margin: auto 0 0;
  padding-top: 14px;
  border-top: 1px solid var(--c-border);
}

.stats div {
  display: flex;
  flex-direction: column-reverse;
}

.stats dt {
  color: var(--c-muted);
  font-size: 0.875rem;
}

.stats dd {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 600;
  line-height: 1.15;
}

/* Real sizes */

.fact {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 24px;
}

.fact h3 {
  font-size: 1.125rem;
}

.fact-ratio {
  margin: 0;
  color: var(--c-primary);
  font-family: var(--font-display);
  font-size: 3rem;
  font-weight: 700;
  line-height: 1;
}

.fact-ratio span {
  margin-left: 2px;
  color: var(--c-muted);
  font-size: 1.125rem;
  font-weight: 500;
}

.compare {
  display: grid;
  gap: 10px;
  margin: 0;
  padding: 0;
  font-size: 0.9375rem;
  list-style: none;
}

.compare b {
  font-weight: 600;
}

.bar {
  display: block;
  width: var(--w);
  height: 10px;
  margin-top: 4px;
  border-radius: 999px;
  background: var(--c-primary);
}

.compare li + li .bar {
  background: var(--c-ruler);
}

.fact-note {
  margin: auto 0 0;
}

/* Line up title, ratio, bars and note across the three cards. */
@supports (grid-template-rows: subgrid) {
  .fact {
    display: grid;
    grid-row: span 4;
    grid-template-rows: subgrid;
    row-gap: 14px;
  }
}

@keyframes bar-grow {
  from {
    width: 0;
  }
}

@media (prefers-reduced-motion: no-preference) {
  @supports (animation-timeline: view()) {
    .bar {
      animation: bar-grow linear both;
      animation-timeline: view();
      animation-range: entry 10% cover 35%;
    }
  }
}

/* Scoring */

.scoring {
  display: grid;
  gap: 28px 48px;
  margin-top: 28px;
  padding: 28px;
}

.scoring-main > p {
  margin: 0;
  font-size: 1.0625rem;
}

.score-stats {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 16px;
  margin: 24px 0 0;
  padding: 0;
  list-style: none;
}

.score-stats b {
  display: block;
  color: var(--c-primary);
  font-family: var(--font-display);
  font-size: clamp(2.25rem, 1.95rem + 1.2vw, 3rem);
  font-weight: 700;
  line-height: 1;
}

.score-stats span {
  display: block;
  margin-top: 8px;
  color: var(--c-muted);
  font-size: 0.9375rem;
  line-height: 1.4;
}

.ratings-title {
  margin: 0 0 10px;
  color: var(--c-muted);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.ratings {
  margin: 0;
  padding: 0;
  border: 1px solid var(--c-border);
  border-radius: var(--radius-sm);
  list-style: none;
}

.ratings li {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  padding: 9px 16px;
}

.ratings li + li {
  border-top: 1px solid var(--c-border);
}

.ratings li span:first-child {
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 600;
}

.ratings li span:last-child {
  color: var(--c-muted);
  font-variant-numeric: tabular-nums;
}

@media (min-width: 760px) {
  .scoring {
    grid-template-columns: minmax(0, 3fr) minmax(0, 2fr);
    align-items: center;
    padding: 36px;
  }
}

/* FAQ */

.faq {
  margin-top: 28px;
  padding: 4px 24px;
}

.faq-item {
  display: grid;
  gap: 6px 40px;
  padding: 20px 0;
}

.faq-item + .faq-item {
  border-top: 1px solid var(--c-border);
}

.faq-item h3 {
  margin: 0;
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1.35;
}

.faq-item p {
  margin: 0;
}

@media (min-width: 760px) {
  .faq {
    padding: 8px 36px;
  }

  .faq-item {
    grid-template-columns: minmax(0, 2fr) minmax(0, 3fr);
    padding: 24px 0;
  }
}

/* Back to the game */

.cta {
  margin: 0;
  padding-block: 0 88px;
  text-align: center;
}

.button {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 13px 24px;
  border-radius: 999px;
  background: var(--c-primary);
  box-shadow: var(--shadow);
  color: var(--c-card);
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 600;
  line-height: 1.2;
  text-decoration: none;
  transition: background-color 0.2s ease, transform 0.2s ease;
}

.button:hover {
  background: var(--c-primary-600);
  transform: translateY(-1px);
}

.button svg {
  width: 20px;
  height: 20px;
}

/* ---------- Footer ---------- */

.site-footer {
  border-top: 1px solid var(--c-border);
  background: var(--c-card);
  color: var(--c-muted);
  font-size: 0.875rem;
  line-height: 1.5;
}

.site-footer .wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px 24px;
  padding-block: 24px;
}

.site-footer p {
  margin: 0;
}

.site-footer ul {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 20px;
  margin: 0;
  padding: 0;
  list-style: none;
}

.site-footer a {
  color: var(--c-text);
  text-decoration-line: underline;
  text-decoration-color: var(--c-border);
  text-decoration-thickness: 1px;
  text-underline-offset: 3px;
  transition: color 0.2s ease, text-decoration-color 0.2s ease;
}

.site-footer a:hover {
  color: var(--c-primary-600);
  text-decoration-color: currentColor;
}

/* ---------- Text pages (About, Privacy, 404) ---------- */

/* Short pages: keep the footer at the bottom of the window. */
.page-fill {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  min-height: 100dvh;
}

.page-fill > main {
  flex: 1 0 auto;
}

.doc {
  padding-block: 16px 88px;
}

.doc h1 {
  margin: 0;
  font-family: var(--font-display);
  font-size: clamp(2.25rem, 1.8rem + 2vw, 3rem);
  font-weight: 700;
  line-height: 1.1;
}

.doc-meta {
  margin: 8px 0 0;
}

.doc-body {
  max-width: 46rem;
  margin-top: 28px;
  padding: 28px;
}

.doc-body p,
.doc-body ul {
  margin: 10px 0 0;
}

.doc-body > p:first-child {
  margin: 0;
  font-size: 1.0625rem;
}

.doc-body ul {
  padding-left: 1.25rem;
}

.doc-body li + li {
  margin-top: 6px;
}

.doc-body h2 {
  margin: 32px 0 0;
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 600;
  line-height: 1.3;
}

.doc-body h3 {
  margin: 20px 0 0;
  font-family: var(--font-display);
  font-size: 1.0625rem;
  font-weight: 600;
  line-height: 1.35;
}

.doc-body :is(h2, h3) + :is(p, ul) {
  margin-top: 6px;
}

.doc-body a {
  color: var(--c-primary-600);
  text-underline-offset: 3px;
}

.doc-cta {
  max-width: 46rem;
  margin: 28px 0 0;
}

/* ---------- 404 ---------- */

.notfound {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding-block: 32px 96px;
  text-align: center;
}

.nf-code {
  margin: 0;
  color: var(--c-primary);
  font-family: var(--font-display);
  font-size: clamp(4.5rem, 3.5rem + 5vw, 6.5rem);
  font-weight: 700;
  line-height: 1;
  letter-spacing: -0.02em;
}

/* A ruler with one very small ant on it. */
.nf-scene {
  position: relative;
  width: min(100%, 360px);
  height: 64px;
  margin: 12px auto 0;
}

.nf-scene::after {
  content: "";
  position: absolute;
  inset: auto 0 0;
  height: 24px;
  border-top: 2px solid var(--c-ruler);
  background:
    repeating-linear-gradient(90deg, var(--c-ruler) 0 2px, transparent 2px 60px) 0 0 / 100% 14px no-repeat,
    repeating-linear-gradient(90deg, var(--c-ruler) 0 1px, transparent 1px 12px) 0 0 / 100% 8px no-repeat;
}

.nf-ant {
  position: absolute;
  bottom: 24px;
  left: 62%;
  width: 22px;
  height: 22px;
  overflow: visible;
}

.notfound h1 {
  margin: 20px 0 0;
  font-family: var(--font-display);
  font-size: clamp(1.75rem, 1.4rem + 1.6vw, 2.5rem);
  font-weight: 700;
  line-height: 1.15;
  text-wrap: balance;
}

.nf-text {
  max-width: 30rem;
  margin: 12px auto 0;
  font-size: 1.0625rem;
  text-wrap: balance;
}

.nf-cta {
  margin: 32px 0 0;
}

/* ---------- Small screens ---------- */

/* One card per row: put the step number beside its text. */
@media (max-width: 719px) {
  .step {
    display: grid;
    grid-template-columns: auto minmax(0, 1fr);
    column-gap: 16px;
  }

  .step-num {
    grid-row: 1 / span 2;
    margin: 0;
  }
}

/* 矮屏笔记本：标题区压紧，让整张游戏卡片不用滚动就能看全 */
@media (max-height: 860px) and (min-width: 481px) {
  .hero {
    padding-block: 4px 16px;
  }

  .hero h1 {
    font-size: 2.5rem;
  }

  .hero-sub {
    margin-top: 6px;
    font-size: 1rem;
  }
}

@media (max-width: 480px) {
  .hero {
    padding-block: 2px 12px;
  }

  .hero h1 {
    font-size: 2rem;
  }

  .hero-sub {
    margin-top: 4px;
    font-size: 0.9375rem;
    line-height: 1.4;
  }

  .play {
    padding-inline: 8px;
  }

  .section {
    margin-block: 64px;
  }

  .step,
  .mode,
  .fact,
  .scoring,
  .doc-body {
    padding: 20px;
  }

  .faq {
    padding: 0 20px;
  }

  .cta {
    padding-bottom: 64px;
  }

  .site-header .wrap {
    gap: 8px;
    min-height: 56px;
  }

  .brand {
    gap: 6px;
    font-size: 1.0625rem;
  }

  .brand img {
    width: 24px;
    height: 24px;
  }

  .site-nav ul {
    gap: 0;
  }

  .site-nav a {
    padding: 6px 7px;
    font-size: 0.875rem;
  }
}

@media (max-width: 380px) {
  .brand {
    font-size: 1rem;
  }

  .site-nav a {
    padding-inline: 5px;
  }
}

@media (max-width: 359px) {
  .brand-name {
    position: absolute;
    width: 1px;
    height: 1px;
    overflow: hidden;
    clip-path: inset(50%);
    white-space: nowrap;
  }
}