/* ==========================================================================
   モトタビラボ — Night Ride theme
   Dark-first: asphalt panel + headlight amber. Light mode = morning fog.
   ========================================================================== */

:root {
  --bg: #14161b;
  --bg-deep: #0e1013;
  --panel: #1d2129;
  --panel-edge: #2c323d;
  --text: #eae7df;
  --muted: #9aa1ad;
  --amber: #ffb547;
  --amber-deep: #e08a00;
  --amber-glow: rgba(255, 181, 71, 0.18);
  --danger: #ff6b5e;
  --radius: 10px;
  --font-jp: "Zen Kaku Gothic New", "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  --font-num: "Chakra Petch", "Zen Kaku Gothic New", monospace;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #f4f2ec;
    --bg-deep: #e9e6de;
    --panel: #ffffff;
    --panel-edge: #d8d4c9;
    --text: #23252a;
    --muted: #6b7280;
    --amber: #d97e00;
    --amber-deep: #b96a00;
    --amber-glow: rgba(217, 126, 0, 0.12);
  }
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-jp);
  background: var(--bg);
  color: var(--text);
  line-height: 1.85;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  /* asphalt noise */
  background-image:
    radial-gradient(ellipse 120% 60% at 50% -10%, var(--amber-glow), transparent 55%),
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='140' height='140'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.9' numOctaves='2'/%3E%3CfeColorMatrix values='0 0 0 0 0.5 0 0 0 0 0.5 0 0 0 0 0.5 0 0 0 0.035 0'/%3E%3C/filter%3E%3Crect width='140' height='140' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ---------- layout ---------- */

.wrap {
  max-width: 880px;
  margin: 0 auto;
  padding: 0 20px;
}

/* horizon line: the signature motif */
.horizon {
  height: 3px;
  background: linear-gradient(90deg, transparent, var(--amber) 30%, var(--amber) 70%, transparent);
  opacity: 0.85;
  border: none;
}

header.site {
  padding: 20px 0 14px;
  border-bottom: 1px solid var(--panel-edge);
  background: color-mix(in srgb, var(--bg-deep) 70%, transparent);
}

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

.brand {
  font-weight: 900;
  font-size: 1.35rem;
  letter-spacing: 0.06em;
  text-decoration: none;
  color: var(--text);
}

.brand .lab { color: var(--amber); }

nav.site a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
  margin-left: 18px;
}

nav.site a:hover { color: var(--amber); }

main { padding: 40px 0 64px; }

footer.site {
  border-top: 1px solid var(--panel-edge);
  padding: 28px 0 40px;
  color: var(--muted);
  font-size: 0.85rem;
}

footer.site a { color: var(--muted); }
footer.site a:hover { color: var(--amber); }

/* ---------- typography ---------- */

h1 {
  font-size: 1.9rem;
  font-weight: 900;
  letter-spacing: 0.03em;
  line-height: 1.4;
  margin-bottom: 0.6em;
}

h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin: 2.2em 0 0.7em;
  padding-left: 12px;
  border-left: 4px solid var(--amber);
}

p { margin-bottom: 1em; }

.lede { color: var(--muted); font-size: 1.02rem; }

/* ---------- hero ---------- */

.hero { padding: 24px 0 8px; }

.hero .kicker {
  font-family: var(--font-num);
  color: var(--amber);
  font-size: 0.8rem;
  letter-spacing: 0.35em;
  text-transform: uppercase;
  margin-bottom: 10px;
}

/* ---------- tool cards ---------- */

.tools {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(240px, 1fr));
  gap: 16px;
  margin-top: 24px;
}

.tool-card {
  display: block;
  background: var(--panel);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius);
  padding: 20px 18px 18px;
  text-decoration: none;
  color: var(--text);
  position: relative;
  overflow: hidden;
  transition: transform 0.15s ease, border-color 0.15s ease;
}

.tool-card::after {
  content: "";
  position: absolute;
  left: 0; right: 0; bottom: 0;
  height: 2px;
  background: linear-gradient(90deg, var(--amber-deep), var(--amber));
  transform: scaleX(0);
  transform-origin: left;
  transition: transform 0.25s ease;
}

.tool-card:hover { transform: translateY(-2px); border-color: var(--amber-deep); }
.tool-card:hover::after { transform: scaleX(1); }

.tool-card h3 { font-size: 1.05rem; margin-bottom: 6px; }
.tool-card p { color: var(--muted); font-size: 0.88rem; margin: 0; }

.tool-card .soon {
  display: inline-block;
  font-family: var(--font-num);
  font-size: 0.7rem;
  letter-spacing: 0.15em;
  color: var(--amber);
  border: 1px solid var(--amber-deep);
  border-radius: 999px;
  padding: 1px 10px;
  margin-bottom: 8px;
}

.tool-card.disabled { opacity: 0.65; pointer-events: none; }

/* ---------- calculator UI ---------- */

.calc {
  background: var(--panel);
  border: 1px solid var(--panel-edge);
  border-radius: var(--radius);
  padding: 24px 20px;
  margin: 20px 0 28px;
}

.tabs { display: flex; gap: 8px; margin-bottom: 20px; }

.tabs button {
  font-family: var(--font-jp);
  font-size: 0.92rem;
  font-weight: 700;
  color: var(--muted);
  background: transparent;
  border: 1px solid var(--panel-edge);
  border-radius: 999px;
  padding: 8px 16px;
  cursor: pointer;
}

.tabs button[aria-selected="true"] {
  color: var(--bg-deep);
  background: var(--amber);
  border-color: var(--amber);
}

.field { margin-bottom: 16px; }

.field label {
  display: block;
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 6px;
}

.field input {
  width: 100%;
  font-family: var(--font-num);
  font-size: 1.25rem;
  color: var(--text);
  background: var(--bg-deep);
  border: 1px solid var(--panel-edge);
  border-radius: 8px;
  padding: 10px 12px;
}

.field input:focus {
  outline: 2px solid var(--amber);
  outline-offset: 1px;
  border-color: var(--amber);
}

.field .unit { font-size: 0.8rem; color: var(--muted); margin-left: 6px; }

.calc .run {
  font-family: var(--font-jp);
  font-weight: 900;
  font-size: 1rem;
  width: 100%;
  padding: 13px;
  color: #14161b;
  background: linear-gradient(180deg, var(--amber), var(--amber-deep));
  border: none;
  border-radius: 8px;
  cursor: pointer;
  letter-spacing: 0.1em;
}

.calc .run:active { transform: translateY(1px); }

.result {
  margin-top: 20px;
  padding: 18px;
  border-radius: 8px;
  background: var(--bg-deep);
  border: 1px dashed var(--panel-edge);
  text-align: center;
}

.result .num {
  font-family: var(--font-num);
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--amber);
  line-height: 1.2;
}

.result .cap { color: var(--muted); font-size: 0.85rem; }

.error {
  color: var(--danger);
  font-size: 0.88rem;
  margin-top: 10px;
  min-height: 1.2em;
}

/* ---------- article / notes ---------- */

.note {
  font-size: 0.95rem;
}

.note ul { padding-left: 1.4em; margin-bottom: 1em; }

table {
  width: 100%;
  border-collapse: collapse;
  margin: 1em 0;
  font-size: 0.92rem;
}

th, td {
  border: 1px solid var(--panel-edge);
  padding: 8px 10px;
  text-align: left;
}

th { background: var(--panel); }

/* ---------- misc ---------- */

.crumbs { font-size: 0.82rem; color: var(--muted); margin-bottom: 18px; }
.crumbs a { color: var(--muted); }

@media (max-width: 480px) {
  h1 { font-size: 1.5rem; }
  .result .num { font-size: 2rem; }
}