/* ============================================================================
   Ame Linux — Design System
   文芸天国のごとく白い余白 × orangestar の青い透き通る夏 × sacanaction「Ame」の雨
   ========================================================================== */

/* ---------- 1. Tokens ---------------------------------------------------- */

:root {
  /* typography */
  --font-serif: "Noto Serif JP", "Shippori Mincho", "Hiragino Mincho ProN",
    "Yu Mincho", "Songti SC", serif;
  --font-sans: "Inter", "Noto Sans JP", -apple-system, BlinkMacSystemFont,
    "Segoe UI", "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  --font-mono: "JetBrains Mono", ui-monospace, SFMono-Regular, "SF Mono",
    Menlo, Consolas, "Liberation Mono", monospace;

  /* rhythm */
  --measure: 74ch;
  --wide: 1180px;
  --r-xs: 4px;
  --r-sm: 8px;
  --r-md: 14px;
  --r-lg: 22px;
  --r-xl: 32px;
  --r-pill: 999px;

  --sp-1: 4px;
  --sp-2: 8px;
  --sp-3: 12px;
  --sp-4: 16px;
  --sp-5: 24px;
  --sp-6: 32px;
  --sp-7: 48px;
  --sp-8: 64px;
  --sp-9: 96px;
  --sp-10: 140px;

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-soft: cubic-bezier(0.4, 0, 0.2, 1);

  --hdr-h: 62px;
}

/* ---- light : 白い世界 -------------------------------------------------- */
:root,
:root[data-theme="light"] {
  --bg: #ffffff;
  --bg-2: #fbfdff;
  --bg-3: #f2f7fc;
  --bg-warm: #fdfdfe;

  --ink: #121722;
  --ink-2: #414f63;
  --ink-3: #5d6b83;
  --ink-4: #606d84;

  --line: rgba(24, 56, 96, 0.10);
  --line-2: rgba(24, 56, 96, 0.055);
  --line-strong: rgba(24, 56, 96, 0.2);

  --sky-1: #8ed8ff;
  --sky-2: #45a9f0;
  --sky-3: #186db6;
  --sky-deep: #0a4f8f;

  --accent: #0a68b8;
  --accent-ink: #ffffff;
  --accent-soft: rgba(69, 169, 240, 0.12);

  --glass: rgba(255, 255, 255, 0.58);
  --glass-2: rgba(255, 255, 255, 0.78);
  --glass-line: rgba(255, 255, 255, 0.9);
  --glass-edge: rgba(24, 70, 120, 0.11);
  --glass-shadow: 0 1px 2px rgba(20, 50, 90, 0.04),
    0 8px 24px -12px rgba(20, 60, 110, 0.16);
  --glass-shadow-lg: 0 2px 4px rgba(20, 50, 90, 0.05),
    0 24px 60px -28px rgba(16, 70, 130, 0.28);

  --beam-1: rgba(126, 200, 255, 0.5);
  --beam-2: rgba(168, 220, 255, 0.34);
  --glow: rgba(120, 195, 255, 0.5);
  --glow-2: rgba(210, 235, 255, 0.65);

  --rain: rgba(96, 165, 220, 0.3);
  --droplet: rgba(120, 190, 240, 0.55);

  --code-bg: #f6fafd;
  --code-line: rgba(24, 70, 120, 0.09);

  --shadow-text: 0 1px 0 rgba(255, 255, 255, 0.9);
  --sel: rgba(69, 169, 240, 0.22);
  color-scheme: light;
}

/* ---- dark : 夜の雨 ----------------------------------------------------- */
:root[data-theme="dark"] {
  --bg: #05080f;
  --bg-2: #080d17;
  --bg-3: #0c1422;
  --bg-warm: #0a1019;

  --ink: #e9f2fc;
  --ink-2: #aec3db;
  --ink-3: #97a8be;
  --ink-4: #8092a9;

  --line: rgba(150, 200, 255, 0.13);
  --line-2: rgba(150, 200, 255, 0.07);
  --line-strong: rgba(160, 210, 255, 0.28);

  --sky-1: #a8e4ff;
  --sky-2: #55b8ff;
  --sky-3: #2196f0;
  --sky-deep: #7fd0ff;

  --accent: #6ccaff;
  --accent-ink: #04121f;
  --accent-soft: rgba(85, 184, 255, 0.16);

  --glass: rgba(17, 30, 49, 0.55);
  --glass-2: rgba(22, 37, 58, 0.74);
  --glass-line: rgba(180, 225, 255, 0.16);
  --glass-edge: rgba(150, 200, 255, 0.11);
  --glass-shadow: 0 1px 2px rgba(0, 0, 0, 0.3), 0 10px 30px -14px rgba(0, 0, 0, 0.7);
  --glass-shadow-lg: 0 2px 6px rgba(0, 0, 0, 0.4),
    0 30px 70px -30px rgba(0, 0, 0, 0.85);

  --beam-1: rgba(90, 180, 255, 0.4);
  --beam-2: rgba(70, 150, 235, 0.24);
  --glow: rgba(60, 150, 240, 0.42);
  --glow-2: rgba(120, 200, 255, 0.4);

  --rain: rgba(150, 210, 255, 0.28);
  --droplet: rgba(140, 205, 255, 0.5);

  --code-bg: #0a1421;
  --code-line: rgba(150, 200, 255, 0.1);

  --shadow-text: 0 1px 0 rgba(0, 0, 0, 0.5);
  --sel: rgba(85, 184, 255, 0.28);
  color-scheme: dark;
}

/* ---------- 2. Reset ----------------------------------------------------- */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--hdr-h) + 24px);
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.8;
  letter-spacing: 0.012em;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
  transition: background-color 0.6s var(--ease-soft), color 0.4s var(--ease-soft);
}

::selection {
  background: var(--sel);
  color: var(--ink);
}

h1,
h2,
h3,
h4,
h5,
h6 {
  margin: 0;
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.45;
  letter-spacing: 0.01em;
  color: var(--ink);
  text-shadow: var(--shadow-text);
}

p {
  margin: 0;
}

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

img,
svg {
  display: block;
  max-width: 100%;
}

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

input {
  font: inherit;
  color: inherit;
}

ul,
ol {
  margin: 0;
  padding: 0;
}

dl,
dd {
  margin: 0;
}

hr {
  border: 0;
  border-top: 1px solid var(--line);
  margin: var(--sp-8) 0;
}

:focus-visible {
  outline: 2px solid var(--sky-2);
  outline-offset: 3px;
  border-radius: var(--r-xs);
}

:focus:not(:focus-visible) {
  outline: none;
}

/* ---------- 3. Boot / app root ------------------------------------------ */

.boot {
  position: fixed;
  inset: 0;
  display: grid;
  place-content: center;
  justify-items: center;
  gap: var(--sp-4);
  background: var(--bg);
  z-index: 999;
}

.boot-mark {
  width: 46px;
  height: 46px;
  fill: var(--sky-2);
  animation: boot-pulse 1.6s var(--ease-soft) infinite;
}

.boot-text {
  font-family: var(--font-serif);
  font-size: 15px;
  letter-spacing: 0.3em;
  color: var(--ink-3);
}

.boot-dots {
  animation: boot-dots 1.2s steps(4, end) infinite;
}

.boot-noscript {
  max-width: 34ch;
  text-align: center;
  font-size: 13px;
  color: var(--ink-3);
  line-height: 1.9;
}

@keyframes boot-pulse {
  0%, 100% { opacity: 0.35; transform: translateY(0); }
  50% { opacity: 1; transform: translateY(-3px); }
}

@keyframes boot-dots {
  0% { opacity: 0.2; }
  50% { opacity: 1; }
  100% { opacity: 0.2; }
}

#ame-app {
  animation: app-in 0.7s var(--ease-out) both;
}

@keyframes app-in {
  from { opacity: 0; }
  to { opacity: 1; }
}

/* ---------- 4. Sky (背景：青空・光条・雨) --------------------------------- */

.sky {
  position: fixed;
  inset: 0;
  z-index: -2;
  overflow: hidden;
  pointer-events: none;
  background: var(--bg);
}

/* 青空のグラデーション */
.sky-base {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(120% 80% at 50% -18%, var(--glow-2) 0%, transparent 58%),
    radial-gradient(90% 60% at 12% 8%, var(--glow) 0%, transparent 62%),
    radial-gradient(80% 55% at 92% 22%, var(--glow) 0%, transparent 60%),
    linear-gradient(180deg, var(--bg-3) 0%, var(--bg-2) 42%, var(--bg) 100%);
  opacity: 0.9;
}

/* 光条（orangestar） */
.sky-beams {
  position: absolute;
  top: -40vh;
  left: 50%;
  width: 190vmax;
  height: 190vmax;
  margin-left: -95vmax;
  transform-origin: 50% 50%;
  animation: beams-spin 140s linear infinite;
  mix-blend-mode: screen;
  opacity: 0.85;
}

:root[data-theme="dark"] .sky-beams {
  opacity: 0.6;
}

.sky-beam {
  position: absolute;
  top: 0;
  left: 50%;
  width: 34vmax;
  height: 190vmax;
  margin-left: -17vmax;
  transform-origin: 50% 0;
  background: linear-gradient(
    180deg,
    var(--beam-1) 0%,
    var(--beam-2) 42%,
    transparent 88%
  );
  filter: blur(28px);
}

@keyframes beams-spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* 雨 */
.sky-rain {
  position: absolute;
  inset: -10% -10% 0 -10%;
  opacity: 0.75;
}

.raindrop {
  position: absolute;
  top: -12vh;
  width: 1px;
  border-radius: var(--r-pill);
  background: linear-gradient(
    180deg,
    transparent 0%,
    var(--rain) 55%,
    var(--rain) 100%
  );
  transform: rotate(9deg);
  animation: rain-fall linear infinite;
}

@keyframes rain-fall {
  0% { transform: translate3d(0, -14vh, 0) rotate(9deg); opacity: 0; }
  6% { opacity: 1; }
  78% { opacity: 1; }
  100% { transform: translate3d(-9vh, 118vh, 0) rotate(9deg); opacity: 0; }
}

/* 水面のリボン */
.sky-ripple {
  position: absolute;
  border-radius: 50%;
  border: 1px solid var(--droplet);
  opacity: 0;
  animation: ripple linear infinite;
}

@keyframes ripple {
  0% { transform: scale(0.15); opacity: 0; }
  18% { opacity: 0.5; }
  100% { transform: scale(1); opacity: 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .sky-beams,
  .rain-drop,
  .raindrop,
  .sky-ripple {
    animation: none !important;
  }
  .sky-beams { opacity: 0.4; }
  .raindrop { opacity: 0.25; }
}

/* ---------- 5. Layout ---------------------------------------------------- */

.shell {
  position: relative;
  z-index: 1;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

.container {
  width: 100%;
  max-width: var(--wide);
  margin: 0 auto;
  padding: 0 var(--sp-5);
}

.container-narrow {
  width: 100%;
  max-width: 900px;
  margin: 0 auto;
  padding: 0 var(--sp-5);
}

.main {
  flex: 1 0 auto;
  padding-bottom: var(--sp-9);
}

/* ---------- 6. Glass ----------------------------------------------------- */

.glass {
  position: relative;
  background: var(--glass);
  border: 1px solid var(--glass-edge);
  border-radius: var(--r-lg);
  box-shadow: var(--glass-shadow);
  backdrop-filter: blur(22px) saturate(1.5);
  -webkit-backdrop-filter: blur(22px) saturate(1.5);
}

/* 上辺の光を強調する疑似要素 */
.glass::before {
  content: "";
  position: absolute;
  inset: 0;
  border-radius: inherit;
  padding: 1px;
  background: linear-gradient(
    150deg,
    var(--glass-line) 0%,
    transparent 34%,
    transparent 66%,
    var(--glass-line) 100%
  );
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  mask-composite: exclude;
  pointer-events: none;
  opacity: 0.85;
}

:root[data-theme="light"] .glass::before {
  opacity: 1;
}

.glass-hover {
  transition: transform 0.5s var(--ease-out), box-shadow 0.5s var(--ease-out),
    border-color 0.5s var(--ease-out), background-color 0.4s var(--ease-soft);
}

.glass-hover:hover {
  transform: translateY(-3px);
  border-color: var(--line-strong);
  background: var(--glass-2);
  box-shadow: var(--glass-shadow-lg);
}

/* ---------- 7. Header --------------------------------------------------- */

.hdr {
  position: sticky;
  top: 0;
  z-index: 60;
  background: var(--glass-2);
  backdrop-filter: blur(26px) saturate(1.6);
  -webkit-backdrop-filter: blur(26px) saturate(1.6);
  border-bottom: 1px solid var(--line);
  transition: background-color 0.5s var(--ease-soft), border-color 0.5s var(--ease-soft);
}

.hdr-inner {
  display: flex;
  align-items: center;
  gap: var(--sp-5);
  height: var(--hdr-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-3);
  flex-shrink: 0;
}

.brand-mark {
  width: 26px;
  height: 26px;
  overflow: visible;
}

.brand-mark .drop {
  fill: none;
  stroke: var(--sky-2);
  stroke-width: 2.2;
  stroke-linejoin: round;
}

.brand-mark .drop-fill {
  fill: var(--sky-2);
  opacity: 0.16;
}

.brand-mark .arc {
  fill: none;
  stroke: var(--sky-1);
  stroke-width: 1.4;
  stroke-linecap: round;
  opacity: 0.85;
}

.brand-text {
  display: flex;
  flex-direction: column;
  line-height: 1.1;
}

.brand-name {
  font-family: var(--font-serif);
  font-size: 16px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--ink);
}

.brand-kana {
  font-size: 9px;
  letter-spacing: 0.34em;
  color: var(--ink-4);
  text-transform: uppercase;
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--sp-1);
  margin-left: auto;
}

.nav-link {
  position: relative;
  padding: 6px 13px;
  border-radius: var(--r-pill);
  font-size: 13.5px;
  font-weight: 500;
  letter-spacing: 0.03em;
  color: var(--ink-2);
  white-space: nowrap;
  transition: color 0.3s var(--ease-soft), background-color 0.3s var(--ease-soft);
}

.nav-link:hover {
  color: var(--ink);
  background: var(--accent-soft);
}

.nav-link.on {
  color: var(--accent);
  background: var(--accent-soft);
}

.nav-link.on::after {
  content: "";
  position: absolute;
  left: 50%;
  bottom: -1px;
  width: 16px;
  height: 2px;
  margin-left: -8px;
  border-radius: var(--r-pill);
  background: var(--sky-2);
}

.hdr-actions {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  flex-shrink: 0;
}

/* ---------- 8. Theme switch --------------------------------------------- */

.theme-switch {
  position: relative;
  display: inline-flex;
  align-items: center;
  gap: 2px;
  padding: 3px;
  border-radius: var(--r-pill);
  background: var(--bg-3);
  border: 1px solid var(--line);
}

.theme-thumb {
  position: absolute;
  top: 3px;
  bottom: 3px;
  border-radius: var(--r-pill);
  background: var(--bg);
  border: 1px solid var(--line);
  box-shadow: 0 1px 4px rgba(20, 60, 110, 0.12);
  transition: transform 0.45s var(--ease-out), width 0.45s var(--ease-out),
    background-color 0.4s var(--ease-soft);
  pointer-events: none;
  z-index: 0;
}

:root[data-theme="dark"] .theme-thumb {
  background: var(--bg-3);
}

.theme-opt {
  position: relative;
  z-index: 1;
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 5px 9px;
  border-radius: var(--r-pill);
  font-size: 11.5px;
  font-weight: 500;
  letter-spacing: 0.02em;
  color: var(--ink-3);
  transition: color 0.3s var(--ease-soft);
  white-space: nowrap;
}

.theme-opt:hover {
  color: var(--ink-2);
}

.theme-opt.on {
  color: var(--accent);
}

.theme-opt svg {
  width: 13px;
  height: 13px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
}

@media (max-width: 720px) {
  .theme-opt .lbl {
    display: none;
  }
}

/* ---------- 9. Hero ------------------------------------------------------ */

.hero {
  position: relative;
  padding: var(--sp-10) 0 var(--sp-9);
}

.hero-inner {
  max-width: 860px;
}

.hero-kicker {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-3);
  margin-bottom: var(--sp-5);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.24em;
  text-transform: uppercase;
  color: var(--sky-3);
}

:root[data-theme="dark"] .hero-kicker {
  color: var(--sky-1);
}

.hero-kicker::before {
  content: "";
  width: 34px;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--sky-2));
}

.hero h1 {
  font-size: clamp(38px, 6.6vw, 74px);
  font-weight: 500;
  line-height: 1.16;
  letter-spacing: -0.005em;
  margin-bottom: var(--sp-5);
}

.hero h1 .h1-latin {
  font-family: var(--font-serif);
  letter-spacing: 0.02em;
}

.hero h1 .h1-jp {
  display: block;
  margin-top: var(--sp-3);
  font-size: clamp(17px, 2.1vw, 24px);
  font-weight: 400;
  letter-spacing: 0.16em;
  color: var(--ink-3);
}

.hero-lede {
  max-width: 60ch;
  font-family: var(--font-serif);
  font-size: clamp(16px, 1.5vw, 19px);
  font-weight: 400;
  line-height: 2.15;
  color: var(--ink-2);
}

.hero-creed {
  margin-top: var(--sp-6);
  padding: var(--sp-5) var(--sp-6);
  border-left: 2px solid var(--sky-2);
  font-family: var(--font-serif);
  font-size: clamp(17px, 2vw, 22px);
  line-height: 1.95;
  color: var(--ink);
  background: linear-gradient(90deg, var(--accent-soft), transparent 78%);
  border-radius: 0 var(--r-md) var(--r-md) 0;
}

.hero-creed cite {
  display: block;
  margin-top: var(--sp-3);
  font-family: var(--font-sans);
  font-size: 11px;
  font-style: normal;
  letter-spacing: 0.18em;
  color: var(--ink-4);
}

.hero-cta {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-3);
  margin-top: var(--sp-7);
}

/* ---------- 10. Buttons -------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 12px 24px;
  border-radius: var(--r-pill);
  font-size: 14px;
  font-weight: 500;
  letter-spacing: 0.04em;
  white-space: nowrap;
  transition: transform 0.4s var(--ease-out), box-shadow 0.4s var(--ease-out),
    background-color 0.3s var(--ease-soft), border-color 0.3s var(--ease-soft),
    color 0.3s var(--ease-soft);
}

.btn svg {
  width: 15px;
  height: 15px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition: transform 0.4s var(--ease-out);
}

.btn:hover {
  transform: translateY(-2px);
}

.btn:hover svg {
  transform: translateX(3px);
}

.btn-primary {
  color: var(--accent-ink);
  background: linear-gradient(135deg, var(--accent), var(--sky-3));
  box-shadow: 0 4px 16px -4px var(--glow), 0 1px 3px rgba(10, 50, 90, 0.2);
}

.btn-primary:hover {
  box-shadow: 0 10px 30px -6px var(--glow), 0 2px 6px rgba(10, 50, 90, 0.24);
}

.btn-ghost {
  color: var(--ink);
  background: var(--glass);
  border: 1px solid var(--line);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.btn-ghost:hover {
  border-color: var(--line-strong);
  background: var(--glass-2);
}

.btn-sm {
  padding: 8px 15px;
  font-size: 12.5px;
}

.btn-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-3);
}

/* ---------- 11. Sections / typography ----------------------------------- */

.sec {
  padding: var(--sp-8) 0;
}

.sec-head {
  margin-bottom: var(--sp-6);
}

.sec-eyebrow {
  display: block;
  margin-bottom: var(--sp-3);
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.26em;
  text-transform: uppercase;
  color: var(--sky-3);
}

:root[data-theme="dark"] .sec-eyebrow {
  color: var(--sky-1);
}

.sec-title {
  font-size: clamp(24px, 3.1vw, 34px);
  font-weight: 500;
  letter-spacing: 0.02em;
}

.sec-desc {
  max-width: 58ch;
  margin-top: var(--sp-3);
  font-size: 15px;
  line-height: 2;
  color: var(--ink-2);
}

.sec-rule {
  margin-top: var(--sp-5);
  height: 1px;
  border: 0;
  background: linear-gradient(90deg, var(--line-strong), transparent 65%);
}

/* ---------- 12. Grid & cards -------------------------------------------- */

.grid {
  display: grid;
  gap: var(--sp-4);
}

.grid-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(190px, 1fr)); }

.card {
  display: block;
  padding: var(--sp-6);
  border-radius: var(--r-lg);
  color: inherit;
}

.card-kicker {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  margin-bottom: var(--sp-3);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-4);
}

.card-title {
  font-size: 18px;
  font-weight: 600;
  letter-spacing: 0.02em;
  transition: color 0.3s var(--ease-soft);
}

.glass-hover:hover .card-title {
  color: var(--accent);
}

.card-desc {
  margin-top: var(--sp-3);
  font-size: 13.5px;
  line-height: 1.95;
  color: var(--ink-2);
}

.card-more {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  margin-top: var(--sp-4);
  font-size: 12px;
  letter-spacing: 0.06em;
  color: var(--accent);
  opacity: 0.85;
}

.card-more svg {
  width: 13px;
  height: 13px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.9;
  stroke-linecap: round;
  stroke-linejoin: round;
  transition: transform 0.4s var(--ease-out);
}

.glass-hover:hover .card-more svg {
  transform: translateX(4px);
}

/* ---------- 13. Badges / status ----------------------------------------- */

.badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 3px 10px;
  border-radius: var(--r-pill);
  border: 1px solid var(--line);
  background: var(--bg-3);
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0.08em;
  line-height: 1.7;
  white-space: nowrap;
  color: var(--ink-2);
}

.badge-dot {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: currentColor;
  flex-shrink: 0;
}

.badge-ok { color: #0f8a52; border-color: rgba(15, 138, 82, 0.3); background: rgba(15, 138, 82, 0.08); }
.badge-prog { color: var(--sky-3); border-color: rgba(28, 127, 212, 0.3); background: rgba(28, 127, 212, 0.08); }
.badge-todo { color: var(--ink-4); }
.badge-research { color: #7a4fd1; border-color: rgba(122, 79, 209, 0.3); background: rgba(122, 79, 209, 0.08); }

:root[data-theme="dark"] .badge-ok { color: #4fdba0; }
:root[data-theme="dark"] .badge-prog { color: var(--sky-1); }
:root[data-theme="dark"] .badge-research { color: #b79bff; }

.badge-row {
  display: flex;
  flex-wrap: wrap;
  gap: var(--sp-2);
}

/* ---------- 14. Stats ---------------------------------------------------- */

.stats {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
  gap: var(--sp-4);
  padding: var(--sp-6);
}

.stat {
  text-align: center;
}

.stat-num {
  font-family: var(--font-serif);
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 500;
  line-height: 1.2;
  color: var(--sky-3);
  font-variant-numeric: tabular-nums;
}

:root[data-theme="dark"] .stat-num {
  color: var(--sky-1);
}

.stat-lbl {
  margin-top: var(--sp-2);
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-4);
  font-family: var(--font-mono);
}

/* ---------- 15. Page header --------------------------------------------- */

.page-head {
  padding: var(--sp-9) 0 var(--sp-7);
}

.page-title {
  font-size: clamp(30px, 4.6vw, 50px);
  font-weight: 500;
  letter-spacing: 0.015em;
  margin-top: var(--sp-4);
}

.page-lede {
  max-width: 60ch;
  margin-top: var(--sp-4);
  font-family: var(--font-serif);
  font-size: 16px;
  line-height: 2.1;
  color: var(--ink-2);
}

.crumbs {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-4);
}

.crumbs a:hover {
  color: var(--accent);
}

.crumb-sep {
  opacity: 0.5;
}

/* ---------- 16. Doc layout ---------------------------------------------- */

.doc {
  display: grid;
  grid-template-columns: 250px minmax(0, 1fr);
  gap: var(--sp-7);
  align-items: start;
  padding-bottom: var(--sp-9);
}

.doc-side {
  position: sticky;
  top: calc(var(--hdr-h) + 24px);
  max-height: calc(100vh - var(--hdr-h) - 48px);
  overflow-y: auto;
  padding-right: var(--sp-2);
  scrollbar-width: thin;
}

.doc-side::-webkit-scrollbar { width: 4px; }
.doc-side::-webkit-scrollbar-thumb {
  background: var(--line-strong);
  border-radius: var(--r-pill);
}

.side-group {
  margin-bottom: var(--sp-5);
}

.side-label {
  padding: 0 var(--sp-3);
  margin-bottom: var(--sp-2);
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-4);
}

.side-link {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 7px var(--sp-3);
  border-radius: var(--r-sm);
  font-size: 13.5px;
  line-height: 1.5;
  color: var(--ink-2);
  transition: color 0.25s var(--ease-soft), background-color 0.25s var(--ease-soft);
}

.side-link:hover {
  color: var(--ink);
  background: var(--accent-soft);
}

.side-link.on {
  color: var(--accent);
  background: var(--accent-soft);
  font-weight: 500;
}

.side-num {
  font-family: var(--font-mono);
  font-size: 10.5px;
  color: var(--ink-4);
  flex-shrink: 0;
  width: 20px;
}

.side-link.on .side-num {
  color: var(--accent);
}

.side-sub {
  padding: var(--sp-4) var(--sp-3) var(--sp-2);
  font-family: var(--font-mono);
  font-size: 9.5px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-4);
  border-top: 1px solid var(--line-2);
  margin-top: var(--sp-3);
}

.doc-body {
  min-width: 0;
  max-width: var(--measure);
}

/* ---------- 17. Prose ---------------------------------------------------- */

.prose {
  font-size: 15.5px;
  line-height: 2.05;
  color: var(--ink-2);
}

.prose > * + * {
  margin-top: var(--sp-5);
}

.prose h2 {
  position: relative;
  margin-top: var(--sp-8);
  padding-top: var(--sp-6);
  font-size: clamp(21px, 2.4vw, 26px);
  font-weight: 600;
  letter-spacing: 0.02em;
}

.prose h2::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  width: 46px;
  height: 2px;
  background: linear-gradient(90deg, var(--sky-2), transparent);
}

.prose h3 {
  margin-top: var(--sp-6);
  font-size: 18px;
  font-weight: 600;
  letter-spacing: 0.03em;
  color: var(--ink);
}

.prose h4 {
  margin-top: var(--sp-5);
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--ink);
}

.prose strong {
  font-weight: 600;
  color: var(--ink);
}

.prose em {
  font-style: normal;
  background: linear-gradient(transparent 62%, var(--accent-soft) 62%);
  padding: 0 2px;
}

.prose ul,
.prose ol {
  padding-left: 1.35em;
}

.prose li + li {
  margin-top: var(--sp-2);
}

.prose li::marker {
  color: var(--sky-3);
}

.prose blockquote {
  margin: var(--sp-6) 0;
  padding: var(--sp-5) var(--sp-6);
  border-left: 2px solid var(--sky-2);
  border-radius: 0 var(--r-md) var(--r-md) 0;
  background: var(--bg-3);
  font-family: var(--font-serif);
  font-size: 16px;
  line-height: 2;
  color: var(--ink);
}

.prose blockquote p + p {
  margin-top: var(--sp-4);
}

.prose a:not(.btn) {
  color: var(--accent);
  text-decoration: underline;
  text-decoration-color: var(--accent-soft);
  text-underline-offset: 3px;
  text-decoration-thickness: 1px;
  transition: text-decoration-color 0.3s var(--ease-soft);
}

.prose a:not(.btn):hover {
  text-decoration-color: var(--sky-2);
}

.prose hr {
  margin: var(--sp-7) 0;
}

.prose code:not(pre code) {
  padding: 2px 6px;
  border-radius: var(--r-xs);
  border: 1px solid var(--code-line);
  background: var(--code-bg);
  font-family: var(--font-mono);
  font-size: 0.855em;
  color: var(--sky-3);
  word-break: break-word;
}

:root[data-theme="dark"] .prose code:not(pre code) {
  color: var(--sky-1);
}

/* ---------- 18. Code blocks --------------------------------------------- */

.code {
  position: relative;
  border-radius: var(--r-md);
  border: 1px solid var(--code-line);
  background: var(--code-bg);
  overflow: hidden;
}

.code-head {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
  padding: 8px var(--sp-4);
  border-bottom: 1px solid var(--code-line);
  background: var(--bg-3);
}

.code-dots {
  display: flex;
  gap: 5px;
}

.code-dots i {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--line-strong);
  display: block;
}

.code-title {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink-4);
}

.code-lang {
  margin-left: auto;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-4);
}

.code pre {
  margin: 0;
  padding: var(--sp-4) var(--sp-5);
  overflow-x: auto;
  font-family: var(--font-mono);
  font-size: 12.8px;
  line-height: 1.85;
  color: var(--ink-2);
  tab-size: 4;
}

.code pre code {
  font-family: inherit;
  background: none;
  border: 0;
  padding: 0;
  color: inherit;
  font-size: inherit;
}

.code pre::-webkit-scrollbar { height: 6px; }
.code pre::-webkit-scrollbar-thumb {
  background: var(--line-strong);
  border-radius: var(--r-pill);
}

/* ---------- 19. Tables --------------------------------------------------- */

.tbl-wrap {
  overflow-x: auto;
  border: 1px solid var(--line);
  border-radius: var(--r-md);
  background: var(--glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
}

.tbl {
  width: 100%;
  border-collapse: collapse;
  font-size: 13.5px;
}

.tbl th,
.tbl td {
  padding: 11px var(--sp-4);
  text-align: left;
  border-bottom: 1px solid var(--line-2);
  vertical-align: top;
}

.tbl th {
  font-family: var(--font-mono);
  font-size: 10.5px;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--ink-4);
  white-space: nowrap;
  background: var(--bg-3);
}

.tbl td {
  color: var(--ink-2);
}

.tbl tbody tr:last-child td {
  border-bottom: 0;
}

.tbl tbody tr {
  transition: background-color 0.25s var(--ease-soft);
}

.tbl tbody tr:hover {
  background: var(--accent-soft);
}

.tbl td:first-child {
  color: var(--ink);
  font-weight: 500;
}

.tbl code {
  font-family: var(--font-mono);
  font-size: 12px;
  color: var(--sky-3);
}

:root[data-theme="dark"] .tbl code {
  color: var(--sky-1);
}

/* ---------- 20. News / list --------------------------------------------- */

.item {
  display: grid;
  grid-template-columns: 132px minmax(0, 1fr);
  gap: var(--sp-5);
  padding: var(--sp-6);
  align-items: start;
}

.item-date {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--ink-4);
  padding-top: 3px;
  line-height: 1.7;
}

.item-title {
  font-size: 19px;
  font-weight: 600;
  letter-spacing: 0.015em;
  transition: color 0.3s var(--ease-soft);
}

.glass-hover:hover .item-title {
  color: var(--accent);
}

.item-sum {
  margin-top: var(--sp-3);
  font-size: 13.5px;
  line-height: 1.95;
  color: var(--ink-2);
}

.item-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--sp-2);
  margin-top: var(--sp-4);
}

@media (max-width: 640px) {
  .item {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--sp-3);
  }
  .item-date {
    padding-top: 0;
  }
}

/* ---------- 21. Article -------------------------------------------------- */

.article {
  max-width: 720px;
  margin: 0 auto;
}

.article-meta {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--sp-3);
  padding-bottom: var(--sp-5);
  margin-bottom: var(--sp-6);
  border-bottom: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--ink-4);
}

.article h1 {
  font-size: clamp(27px, 4.2vw, 42px);
  font-weight: 500;
  line-height: 1.35;
  letter-spacing: 0.015em;
  margin-bottom: var(--sp-4);
}

.article-lede {
  font-family: var(--font-serif);
  font-size: 17px;
  line-height: 2.1;
  color: var(--ink-2);
}

/* ---------- 22. Search --------------------------------------------------- */

.search {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  padding: 12px var(--sp-5);
  border-radius: var(--r-pill);
}

.search svg {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  fill: none;
  stroke: var(--ink-4);
  stroke-width: 1.8;
  stroke-linecap: round;
}

.search input {
  flex: 1;
  min-width: 0;
  border: 0;
  outline: none;
  background: none;
  font-size: 14.5px;
  letter-spacing: 0.02em;
  color: var(--ink);
}

.search input::placeholder {
  color: var(--ink-4);
}

.search-count {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  color: var(--ink-4);
  white-space: nowrap;
}

.search-clear {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  color: var(--ink-4);
  transition: background-color 0.25s var(--ease-soft), color 0.25s var(--ease-soft);
}

.search-clear:hover {
  background: var(--accent-soft);
  color: var(--accent);
}

/* 検索欄のラッパと結果パネル */

.search-wrap {
  position: relative;
  z-index: 20;
}

.search-panel {
  position: absolute;
  left: 0;
  right: 0;
  top: calc(100% + 8px);
  max-height: 62vh;
  overflow-y: auto;
  padding: var(--sp-4) 0;
  z-index: 30;
}

.search-count {
  padding: 0 var(--sp-5) var(--sp-3);
  border-bottom: 1px solid var(--line-2);
  margin-bottom: var(--sp-2);
  white-space: normal;
}

.search-hit {
  display: grid;
  grid-template-columns: 84px minmax(0, 1fr);
  gap: 2px var(--sp-4);
  padding: var(--sp-3) var(--sp-5);
  transition: background-color 0.2s var(--ease-soft);
}

.search-hit:hover {
  background: var(--bg-3);
}

.search-kind {
  grid-row: 1 / span 2;
  font-size: 9.5px;
  letter-spacing: 0.1em;
  color: var(--sky-3);
  padding-top: 3px;
}

:root[data-theme="dark"] .search-kind {
  color: var(--sky-1);
}

.search-hit-t {
  font-size: 14px;
  font-weight: 600;
  color: var(--ink);
}

.search-sum {
  font-size: 12px;
  line-height: 1.7;
}

@media (max-width: 560px) {
  .search-hit {
    grid-template-columns: minmax(0, 1fr);
  }

  .search-kind {
    grid-row: auto;
  }
}

mark {
  background: linear-gradient(transparent 58%, var(--accent-soft) 58%);
  color: inherit;
  padding: 0 1px;
}

/* ---------- 23. TOC (in-article) ---------------------------------------- */

.toc {
  padding: var(--sp-5);
  border-radius: var(--r-md);
}

.toc-title {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-4);
  margin-bottom: var(--sp-3);
}

.toc a {
  display: block;
  padding: 4px 0 4px var(--sp-3);
  border-left: 2px solid var(--line);
  font-size: 13px;
  line-height: 1.7;
  color: var(--ink-3);
  transition: color 0.25s var(--ease-soft), border-color 0.25s var(--ease-soft);
}

.toc a:hover {
  color: var(--accent);
  border-left-color: var(--sky-2);
}

/* ---------- 24. Layer diagram ------------------------------------------- */

.layers {
  display: flex;
  flex-direction: column-reverse;
  gap: 2px;
}

.layer {
  display: grid;
  grid-template-columns: 74px 1fr auto;
  gap: var(--sp-4);
  align-items: center;
  padding: var(--sp-4) var(--sp-5);
  border-radius: var(--r-sm);
  background: var(--glass);
  border: 1px solid var(--glass-edge);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: transform 0.4s var(--ease-out), border-color 0.3s var(--ease-soft);
}

.layer:hover {
  transform: translateX(4px);
  border-color: var(--line-strong);
}

.layer-n {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  color: var(--sky-3);
}

:root[data-theme="dark"] .layer-n {
  color: var(--sky-1);
}

.layer-name {
  font-family: var(--font-serif);
  font-size: 15.5px;
  font-weight: 600;
  letter-spacing: 0.02em;
}

.layer-desc {
  font-size: 12.5px;
  line-height: 1.7;
  color: var(--ink-3);
  margin-top: 2px;
}

@media (max-width: 640px) {
  .layer {
    grid-template-columns: 60px 1fr;
  }
  .layer .badge {
    grid-column: 2;
    justify-self: start;
  }
}

/* ---------- 25. ISO / release ------------------------------------------- */

.release {
  padding: var(--sp-6);
}

.release-top {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-start;
  gap: var(--sp-4);
  justify-content: space-between;
}

.release-ver {
  font-family: var(--font-serif);
  font-size: 26px;
  font-weight: 600;
  letter-spacing: 0.03em;
}

.release-date {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.12em;
  color: var(--ink-4);
  margin-top: 4px;
}

.release-note {
  margin-top: var(--sp-4);
  font-size: 13.5px;
  line-height: 1.95;
  color: var(--ink-2);
}

.assets {
  margin-top: var(--sp-5);
  border-top: 1px solid var(--line-2);
}

.asset {
  display: grid;
  grid-template-columns: minmax(0, 1fr) auto auto;
  gap: var(--sp-4);
  align-items: center;
  padding: var(--sp-4) 0;
  border-bottom: 1px solid var(--line-2);
}

.asset:last-child {
  border-bottom: 0;
}

.asset-name {
  display: flex;
  align-items: center;
  gap: var(--sp-3);
  font-family: var(--font-mono);
  font-size: 13px;
  color: var(--ink);
  word-break: break-all;
}

.asset-ico {
  width: 26px;
  height: 26px;
  flex-shrink: 0;
  display: grid;
  place-items: center;
  border-radius: var(--r-xs);
  background: var(--bg-3);
  border: 1px solid var(--line);
  font-family: var(--font-mono);
  font-size: 8px;
  font-weight: 600;
  letter-spacing: 0.02em;
  color: var(--sky-3);
}

:root[data-theme="dark"] .asset-ico {
  color: var(--sky-1);
}

.asset-meta {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink-4);
  white-space: nowrap;
}

@media (max-width: 700px) {
  .asset {
    grid-template-columns: minmax(0, 1fr) auto;
  }
  .asset-meta {
    grid-column: 1 / -1;
  }
}

/* ---------- 26. Term / dl ----------------------------------------------- */

.terms {
  display: grid;
  gap: var(--sp-3);
  margin: 0;
}

.term {
  display: grid;
  grid-template-columns: minmax(150px, 200px) minmax(0, 1fr);
  gap: var(--sp-4);
  padding: var(--sp-4) 0;
  border-bottom: 1px solid var(--line-2);
}

.term:last-child {
  border-bottom: 0;
}

.term-k {
  font-family: var(--font-serif);
  font-size: 15px;
  font-weight: 600;
  color: var(--ink);
  letter-spacing: 0.02em;
}

.term-v {
  font-size: 13.5px;
  line-height: 1.95;
  color: var(--ink-2);
}

@media (max-width: 640px) {
  .term {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--sp-2);
  }
}

/* ---------- 27. Steps --------------------------------------------------- */

.steps {
  display: grid;
  gap: var(--sp-3);
  counter-reset: step;
}

.step {
  display: grid;
  grid-template-columns: 40px minmax(0, 1fr);
  gap: var(--sp-4);
  padding: var(--sp-5);
  border-radius: var(--r-md);
}

.step-n {
  display: grid;
  place-items: center;
  width: 34px;
  height: 34px;
  border-radius: 50%;
  border: 1px solid var(--line-strong);
  background: var(--bg);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  color: var(--sky-3);
}

:root[data-theme="dark"] .step-n {
  color: var(--sky-1);
}

.step-t {
  font-family: var(--font-serif);
  font-size: 16.5px;
  font-weight: 600;
  letter-spacing: 0.02em;
  margin-bottom: var(--sp-2);
}

.step-d {
  font-size: 13.5px;
  line-height: 1.95;
  color: var(--ink-2);
}

/* ---------- 28. Principles --------------------------------------------- */

.principle {
  padding: var(--sp-5);
  border-radius: var(--r-md);
  position: relative;
  overflow: hidden;
}

.principle-n {
  position: absolute;
  top: -6px;
  right: var(--sp-4);
  font-family: var(--font-serif);
  font-size: 64px;
  font-weight: 700;
  line-height: 1;
  color: var(--sky-2);
  opacity: 0.11;
  pointer-events: none;
}

.principle-t {
  font-family: var(--font-serif);
  font-size: 17px;
  font-weight: 600;
  letter-spacing: 0.04em;
  color: var(--ink);
}

.principle-d {
  margin-top: var(--sp-3);
  font-size: 13px;
  line-height: 1.95;
  color: var(--ink-2);
}

.principle-x {
  margin-top: var(--sp-3);
  padding-top: var(--sp-3);
  border-top: 1px solid var(--line-2);
  font-size: 12px;
  line-height: 1.85;
  color: var(--ink-3);
}

.principle-x b {
  color: var(--ink-2);
  font-weight: 500;
}

/* ---------- 29. Callout ------------------------------------------------- */

.callout {
  display: grid;
  grid-template-columns: auto minmax(0, 1fr);
  gap: var(--sp-3);
  padding: var(--sp-4) var(--sp-5);
  border-radius: var(--r-md);
  border: 1px solid var(--line);
  background: var(--bg-3);
  font-size: 13.5px;
  line-height: 1.9;
}

.callout-ico {
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.06em;
  color: var(--sky-3);
  padding-top: 2px;
}

:root[data-theme="dark"] .callout-ico {
  color: var(--sky-1);
}

.callout-warn {
  border-color: rgba(200, 120, 20, 0.28);
  background: rgba(200, 120, 20, 0.06);
}

.callout-warn .callout-ico {
  color: #96640c;
}

:root[data-theme="dark"] .callout-warn .callout-ico {
  color: #ffc061;
}

.callout-danger {
  border-color: rgba(200, 50, 50, 0.28);
  background: rgba(200, 50, 50, 0.06);
}

.callout-danger .callout-ico {
  color: #b33232;
}

:root[data-theme="dark"] .callout-danger .callout-ico {
  color: #ff8a8a;
}

.callout p + p {
  margin-top: var(--sp-2);
}

/* ---------- 30. Footer -------------------------------------------------- */

.ftr {
  margin-top: var(--sp-9);
  border-top: 1px solid var(--line);
  background: var(--glass);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
}

.ftr-top {
  display: grid;
  grid-template-columns: minmax(220px, 1.4fr) repeat(auto-fit, minmax(140px, 1fr));
  gap: var(--sp-6);
  padding: var(--sp-8) 0 var(--sp-6);
}

.ftr-brand {
  max-width: 40ch;
}

.ftr-tag {
  margin-top: var(--sp-4);
  font-family: var(--font-serif);
  font-size: 13.5px;
  line-height: 2;
  color: var(--ink-3);
}

.ftr-col-title {
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.2em;
  text-transform: uppercase;
  color: var(--ink-4);
  margin-bottom: var(--sp-4);
}

.ftr-link {
  display: block;
  padding: 4px 0;
  font-size: 13px;
  color: var(--ink-2);
  transition: color 0.25s var(--ease-soft), transform 0.35s var(--ease-out);
}

.ftr-link:hover {
  color: var(--accent);
  transform: translateX(3px);
}

.ftr-bottom {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: var(--sp-4);
  justify-content: space-between;
  padding: var(--sp-5) 0;
  border-top: 1px solid var(--line-2);
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.06em;
  color: var(--ink-4);
}

/* ---------- 31. Utilities ---------------------------------------------- */

.stack-2 > * + * { margin-top: var(--sp-2); }
.stack-3 > * + * { margin-top: var(--sp-3); }
.stack-4 > * + * { margin-top: var(--sp-4); }
.stack-5 > * + * { margin-top: var(--sp-5); }
.stack-6 > * + * { margin-top: var(--sp-6); }
.stack-7 > * + * { margin-top: var(--sp-7); }

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

.dim {
  color: var(--ink-3);
}

.dim-2 {
  color: var(--ink-4);
}

.tiny {
  font-size: 12px;
}

.center {
  text-align: center;
}

.nowrap {
  white-space: nowrap;
}

.mt-2 { margin-top: var(--sp-2); }
.mt-3 { margin-top: var(--sp-3); }
.mt-4 { margin-top: var(--sp-4); }
.mt-5 { margin-top: var(--sp-5); }
.mt-6 { margin-top: var(--sp-6); }
.mt-7 { margin-top: var(--sp-7); }
.mt-8 { margin-top: var(--sp-8); }

.mb-4 { margin-bottom: var(--sp-4); }
.mb-5 { margin-bottom: var(--sp-5); }
.mb-6 { margin-bottom: var(--sp-6); }
.mb-7 { margin-bottom: var(--sp-7); }
.mb-8 { margin-bottom: var(--sp-8); }

.mt-2 › * + *, .mt-3 › * + *, .mt-4 › * + * {
  margin-top: 0;
}

.flex {
  display: flex;
}

.flex-wrap {
  flex-wrap: wrap;
}

.items-center {
  align-items: center;
}

.gap-2 { gap: var(--sp-2); }
.gap-3 { gap: var(--sp-3); }
.gap-4 { gap: var(--sp-4); }

.between {
  justify-content: space-between;
}

/* ---------- 32. Mobile nav --------------------------------------------- */

.burger {
  display: none;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: var(--r-sm);
  border: 1px solid var(--line);
  background: var(--bg-3);
  color: var(--ink-2);
}

.burger svg {
  width: 17px;
  height: 17px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.8;
  stroke-linecap: round;
}

@media (max-width: 900px) {
  .burger {
    display: inline-flex;
    order: 3;
  }
  .nav {
    position: fixed;
    inset: var(--hdr-h) 0 auto 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    margin: 0;
    padding: var(--sp-4) var(--sp-5) var(--sp-6);
    background: var(--bg-2);
    border-bottom: 1px solid var(--line);
    backdrop-filter: blur(26px);
    -webkit-backdrop-filter: blur(26px);
    transform: translateY(-8px);
    opacity: 0;
    pointer-events: none;
    /* visibility を落とさないと、閉じた nav のリンクにキーボードフォーカスが
       当たる（透明な看不见リンクに Tab できてしまう）。 */
    visibility: hidden;
    transition: opacity 0.3s var(--ease-soft), transform 0.3s var(--ease-out),
      visibility 0s linear 0.3s;
    max-height: calc(100vh - var(--hdr-h));
    overflow-y: auto;
  }
  .nav.open {
    opacity: 1;
    transform: translateY(0);
    pointer-events: auto;
    visibility: visible;
    transition: opacity 0.3s var(--ease-soft), transform 0.3s var(--ease-out),
      visibility 0s linear 0s;
  }
  .nav-link {
    padding: 12px var(--sp-3);
    border-radius: var(--r-sm);
    font-size: 15px;
  }
  .nav-link.on::after {
    display: none;
  }
  .nav-link.on {
    border-left: 2px solid var(--sky-2);
  }
  .doc {
    grid-template-columns: minmax(0, 1fr);
    gap: var(--sp-5);
  }
  .doc-side {
    position: static;
    max-height: none;
    padding: var(--sp-4);
    border-radius: var(--r-md);
    background: var(--glass);
    border: 1px solid var(--line);
  }
  .hero {
    padding: var(--sp-8) 0 var(--sp-7);
  }
  .page-head {
    padding: var(--sp-7) 0 var(--sp-5);
  }
  .ftr-top {
    padding: var(--sp-6) 0 var(--sp-5);
  }
}

@media (max-width: 520px) {
  .container,
  .container-narrow {
    padding: 0 var(--sp-4);
  }
  .brand-kana {
    display: none;
  }
}

/* ---------- 33. Route transition --------------------------------------- */

.fade-in {
  animation: fade-in 0.45s var(--ease-out) both;
}

@keyframes fade-in {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

/* skip link */
.skip {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 200;
  padding: 10px 18px;
  background: var(--bg);
  border: 1px solid var(--line);
  border-radius: 0 0 var(--r-sm) 0;
  font-size: 13px;
}

.skip:focus {
  left: 0;
}

/* print */
@media print {
  .sky, .hdr, .ftr, .doc-side, .theme-switch, .btn-row { display: none !important; }
  body { background: #fff; color: #000; }
  .glass { box-shadow: none; background: #fff; border-color: #ccc; }
}
/* ---------- 33. 追加ユーティリティ ---------------------------------------- */

.dot {
  display: inline-block;
  width: 3px;
  height: 3px;
  border-radius: 50%;
  background: currentColor;
  opacity: 0.55;
  margin: 0 0.6em;
  vertical-align: middle;
}

.theme-ico {
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.theme-ico svg {
  width: 14px;
  height: 14px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.7;
  stroke-linecap: round;
}

.badge-warn {
  color: #8d5a0c;
  border-color: rgba(141, 90, 12, 0.3);
  background: rgba(164, 105, 14, 0.09);
}

:root[data-theme="dark"] .badge-warn {
  color: #e0a83a;
}

.is-disabled,
[aria-disabled="true"] {
  opacity: 0.45;
  pointer-events: none;
  cursor: not-allowed;
}

.prose-html > *:first-child {
  margin-top: 0;
}

.prose-html > * + * {
  margin-top: var(--sp-4);
}