:root {
  --bg: #f4f5f9;
  --surface: #ffffff;
  --surface-2: #f0f1f6;
  --text: #171a23;
  --muted: #5b6273;
  --border: #dfe2ea;
  --accent: #4338ca;
  --accent-hover: #3730a3;
  --accent-contrast: #ffffff;
  --focus: #6366f1;
  --digit: #1d4ed8;
  --symbol: #b45309;
  --danger: #b91c1c;
  --s0: #dc2626;
  --s1: #ea580c;
  --s2: #ca8a04;
  --s3: #16a34a;
  --s4: #15803d;
  --radius: 14px;
  --mono: ui-monospace, 'SF Mono', Menlo, Consolas, monospace;
  color-scheme: light;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0f1117;
    --surface: #181b24;
    --surface-2: #11141b;
    --text: #e8eaf0;
    --muted: #9aa1b2;
    --border: #2a2f3c;
    --accent: #818cf8;
    --accent-hover: #a5b4fc;
    --accent-contrast: #0f1117;
    --focus: #a5b4fc;
    --digit: #7dd3fc;
    --symbol: #fdba74;
    --danger: #f87171;
    --s0: #f87171;
    --s1: #fb923c;
    --s2: #facc15;
    --s3: #4ade80;
    --s4: #22c55e;
    color-scheme: dark;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
}

.app {
  max-width: 640px;
  margin: 0 auto;
  padding: 32px 16px 64px;
  display: grid;
  gap: 16px;
}

.app-header h1 { margin: 0; font-size: 1.75rem; letter-spacing: -0.01em; }
.tagline { margin: 4px 0 0; color: var(--muted); }

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.tabs {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 4px;
  padding: 4px;
  background: var(--surface-2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}
.tabs button {
  border: 0;
  background: transparent;
  color: var(--muted);
  padding: 8px 4px;
  border-radius: 10px;
  font: inherit;
  font-weight: 600;
  font-size: 0.9rem;
  cursor: pointer;
}
.tabs button[aria-selected='true'] {
  background: var(--surface);
  color: var(--text);
  box-shadow: 0 1px 3px rgb(0 0 0 / 0.12);
}

.result-card { display: grid; gap: 12px; }
.result {
  font-family: var(--mono);
  font-size: 1.35rem;
  line-height: 1.4;
  word-break: break-all;
  padding: 16px;
  min-height: 64px;
  background: var(--surface-2);
  border: 1px dashed var(--border);
  border-radius: 10px;
  cursor: copy;
}
.result.multi { font-size: 0.95rem; }
.result ol { margin: 0; padding-left: 2.2em; }
.result li + li { margin-top: 4px; }
.c-digit { color: var(--digit); }
.c-symbol { color: var(--symbol); }
.c-space { color: var(--muted); }

.error { margin: 0; color: var(--danger); font-weight: 500; }

.meter { display: grid; grid-template-columns: repeat(5, 1fr); gap: 4px; }
.meter span { height: 6px; border-radius: 3px; background: var(--border); transition: background 0.2s; }
.strength[data-level='0'] .meter span:nth-child(-n + 1) { background: var(--s0); }
.strength[data-level='1'] .meter span:nth-child(-n + 2) { background: var(--s1); }
.strength[data-level='2'] .meter span:nth-child(-n + 3) { background: var(--s2); }
.strength[data-level='3'] .meter span:nth-child(-n + 4) { background: var(--s3); }
.strength[data-level='4'] .meter span:nth-child(-n + 5) { background: var(--s4); }
.strength-text { margin: 6px 0 0; font-size: 0.85rem; color: var(--muted); }

.primary {
  font: inherit;
  font-weight: 700;
  font-size: 1.05rem;
  padding: 14px 20px;
  border: 0;
  border-radius: 12px;
  background: var(--accent);
  color: var(--accent-contrast);
  cursor: pointer;
  transition: background 0.15s, transform 0.05s;
}
.primary:hover { background: var(--accent-hover); }
.primary:active { transform: scale(0.99); }

.hint { margin: 0; text-align: center; font-size: 0.85rem; color: var(--muted); }
kbd {
  font-family: var(--mono);
  font-size: 0.8em;
  padding: 1px 6px;
  border: 1px solid var(--border);
  border-bottom-width: 2px;
  border-radius: 5px;
  background: var(--surface-2);
}

.panel { display: grid; gap: 18px; }
.panel-intro { margin: 0; color: var(--muted); font-size: 0.95rem; }

.presets { display: flex; flex-wrap: wrap; gap: 8px; align-items: center; }
.presets-label { font-size: 0.8rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.05em; color: var(--muted); margin-right: 4px; }
.chip {
  font: inherit;
  font-size: 0.85rem;
  padding: 4px 12px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--surface-2);
  color: var(--text);
  cursor: pointer;
}
.chip:hover { border-color: var(--accent); }

.field { display: grid; gap: 6px; }
.field > label, legend { font-weight: 600; font-size: 0.95rem; }
.field small { color: var(--muted); }

.range-row { display: grid; grid-template-columns: 1fr 80px; gap: 12px; align-items: center; }
input[type='range'] { width: 100%; accent-color: var(--accent); }

input[type='number'], input[type='text'], select {
  font: inherit;
  width: 100%;
  padding: 8px 10px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--surface-2);
  color: var(--text);
}
input[type='text'] { font-family: var(--mono); }

fieldset.checks { border: 0; margin: 0; padding: 0; display: grid; gap: 8px; }
fieldset.checks legend { padding: 0; margin-bottom: 6px; }
fieldset.checks label { display: flex; gap: 10px; align-items: center; cursor: pointer; flex-wrap: wrap; }
input[type='checkbox'] { width: 18px; height: 18px; accent-color: var(--accent); margin: 0; }
code { font-family: var(--mono); font-size: 0.85em; color: var(--muted); }

details summary { cursor: pointer; font-weight: 600; }
details[open] { display: grid; gap: 16px; }

.link {
  font: inherit;
  font-size: 0.85rem;
  background: none;
  border: 0;
  padding: 0;
  color: var(--accent);
  cursor: pointer;
  justify-self: start;
}
.link:hover { text-decoration: underline; }

.history-head { display: flex; justify-content: space-between; align-items: baseline; }
.history-head h2 { margin: 0; font-size: 1.1rem; }
.history { list-style: none; margin: 8px 0 0; padding: 0; display: grid; gap: 8px; }
.history li { display: flex; gap: 12px; align-items: center; flex-wrap: wrap; }
.history li code { flex: 1 1 200px; min-width: 0; word-break: break-all; color: var(--text); font-size: 0.9rem; }
.history li code.masked { color: var(--muted); letter-spacing: 0.1em; }
.muted { color: var(--muted); }
.small { font-size: 0.85rem; margin: 0; }

.toast {
  position: fixed;
  left: 50%;
  bottom: 24px;
  transform: translate(-50%, 20px);
  background: var(--text);
  color: var(--bg);
  padding: 10px 18px;
  border-radius: 999px;
  font-weight: 600;
  font-size: 0.95rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s, transform 0.2s;
  max-width: calc(100% - 32px);
  text-align: center;
}
.toast.show { opacity: 1; transform: translate(-50%, 0); }

:focus-visible { outline: 2px solid var(--focus); outline-offset: 2px; }

[hidden] { display: none !important; }

@media (max-width: 420px) {
  .tabs button { font-size: 0.8rem; }
  .result { font-size: 1.1rem; }
}

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; }
}