:root {
  --bg: #f7f7f5;
  --fg: #0b0d10;
  --muted: #6b6f76;
  --accent: #0b0d10;
  --accent-fg: #f7f7f5;
  --border: #e2e2dc;
  --card: #ffffff;
  --radius: 14px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0d10;
    --fg: #f1f1ee;
    --muted: #8a8f96;
    --accent: #f1f1ee;
    --accent-fg: #0b0d10;
    --border: #1f232a;
    --card: #14171c;
  }
}

* { box-sizing: border-box; }

html, body {
  margin: 0;
  padding: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: -apple-system, BlinkMacSystemFont, "Inter", "Segoe UI", Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
  font-feature-settings: "tnum" 1;
}

body {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
}

a { color: inherit; }

.visually-hidden {
  position: absolute;
  width: 1px; height: 1px;
  margin: -1px; padding: 0; border: 0;
  clip: rect(0 0 0 0); overflow: hidden;
  white-space: nowrap;
}

.lang {
  position: fixed;
  top: max(env(safe-area-inset-top), 14px);
  right: 16px;
  font-size: 14px;
  display: flex; gap: 8px; align-items: center;
  color: var(--muted);
  z-index: 10;
}
.lang a { text-decoration: none; padding: 4px 6px; border-radius: 6px; }
.lang a[aria-current="page"] { color: var(--fg); font-weight: 600; }

main {
  flex: 1;
  width: 100%;
  max-width: 560px;
  margin: 0 auto;
  padding: 0 20px 40px;
  display: flex;
  flex-direction: column;
}

.clock {
  min-height: 100dvh;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 8px;
}

.date {
  font-size: clamp(13px, 3.5vw, 16px);
  color: var(--muted);
  letter-spacing: 0.04em;
  margin-bottom: 14px;
  font-weight: 500;
}

.time {
  font-size: clamp(64px, 20vw, 144px);
  font-weight: 600;
  letter-spacing: -0.04em;
  line-height: 1;
  font-variant-numeric: tabular-nums;
}
.time .sec {
  color: var(--muted);
}

.suffix {
  font-size: clamp(28px, 8vw, 56px);
  font-weight: 500;
  color: var(--muted);
  letter-spacing: 0.04em;
  min-height: 1em;
}

.toggle {
  margin-top: 28px;
  display: inline-flex;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 4px;
  gap: 2px;
}
.toggle button {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--muted);
  font: inherit;
  font-size: 14px;
  padding: 10px 18px;
  border-radius: 999px;
  cursor: pointer;
  transition: background .15s, color .15s;
}
.toggle button[aria-selected="true"] {
  background: var(--accent);
  color: var(--accent-fg);
}

.converter, .explainer {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 24px;
  margin-top: 24px;
}

.converter { text-align: center; }

.converter h2, .explainer h2 {
  margin: 0 0 4px;
  font-size: 20px;
  font-weight: 600;
}
.hint {
  margin: 0 0 22px;
  color: var(--muted);
  font-size: 14px;
}

.row { display: flex; flex-direction: column; align-items: center; gap: 10px; }
.row + .arrow { text-align: center; color: var(--muted); margin: 14px 0; font-size: 18px; }
.row label {
  font-size: 13px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.inputs {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  flex-wrap: wrap;
}
.inputs input[type="text"] {
  width: 64px;
  font-size: 28px;
  font-variant-numeric: tabular-nums;
  text-align: center;
  padding: 10px 8px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--bg);
  color: var(--fg);
  font-family: inherit;
}
.inputs input[type="text"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}
.inputs span { font-size: 24px; color: var(--muted); }

.ampm {
  display: inline-flex;
  gap: 6px;
  margin-top: 4px;
}
.ampm label {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  padding: 6px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  font-size: 14px;
  cursor: pointer;
}
.ampm input { accent-color: var(--accent); }

.explainer ul { margin: 8px 0 0; padding-left: 20px; color: var(--muted); line-height: 1.6; }
.explainer strong { color: var(--fg); }

footer {
  text-align: center;
  padding: 24px 16px max(24px, env(safe-area-inset-bottom));
  font-size: 13px;
  color: var(--muted);
}
footer a { color: var(--fg); text-decoration: underline; text-underline-offset: 3px; }