:root {
  --bg: #0b1220;
  --bg-soft: #101a2e;
  --card: #131f36;
  --card-edge: #1e2d4d;
  --text: #e7edf7;
  --muted: #8fa3bf;
  --accent: #22d3ee;
  --accent-strong: #06b6d4;
  --accent-ink: #05242b;
  --danger: #f87171;
  --ok: #34d399;
  --radius: 14px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(1200px 500px at 50% -200px, rgba(34, 211, 238, 0.08), transparent),
    var(--bg);
  color: var(--text);
  font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
}

.skip-link {
  position: absolute;
  left: -999px;
  top: 0;
  background: var(--accent);
  color: var(--accent-ink);
  padding: 8px 14px;
  border-radius: 0 0 8px 0;
  z-index: 10;
}
.skip-link:focus { left: 0; }

.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 16px;
  max-width: 720px;
  margin: 0 auto;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
}
.brand img { width: 30px; height: 30px; }
.brand strong { font-size: 18px; letter-spacing: 0.2px; }
.brand .tagline { display: block; font-size: 12px; color: var(--muted); margin-top: -2px; }

.controls { display: flex; gap: 8px; }

select {
  appearance: none;
  background: var(--bg-soft);
  color: var(--text);
  border: 1px solid var(--card-edge);
  border-radius: 10px;
  padding: 8px 30px 8px 10px;
  font: inherit;
  font-size: 14px;
  background-image: url("data:image/svg+xml;charset=utf8,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M0 0l5 6 5-6z' fill='%238fa3bf'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 10px center;
}

main {
  max-width: 720px;
  margin: 0 auto;
  padding: 4px 16px 48px;
}

.hero { text-align: left; }
.hero h1 { margin: 0 0 6px; font-size: 26px; line-height: 1.25; }
.hero p { margin: 0 0 14px; color: var(--muted); }
.hero .badge-c {
  display: inline-block;
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: 11px;
  letter-spacing: 0.4px;
  color: var(--accent);
  border: 1px solid rgba(34, 211, 238, 0.35);
  background: rgba(34, 211, 238, 0.07);
  padding: 3px 9px;
  border-radius: 999px;
  margin-bottom: 12px;
}

.card {
  background: var(--card);
  border: 1px solid var(--card-edge);
  border-radius: var(--radius);
  padding: 16px;
  margin-top: 14px;
}

/* Category chips */
.chips {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 2px;
  scrollbar-width: none;
}
.chips::-webkit-scrollbar { display: none; }
.chip {
  flex: 0 0 auto;
  border: 1px solid var(--card-edge);
  background: var(--bg-soft);
  color: var(--muted);
  border-radius: 999px;
  padding: 8px 14px;
  font: inherit;
  font-size: 14px;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s, background 0.15s;
}
.chip[aria-selected="true"] {
  background: rgba(34, 211, 238, 0.12);
  border-color: var(--accent);
  color: var(--accent);
  font-weight: 600;
}

/* Converter */
.conv-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 10px;
  align-items: end;
  margin-top: 14px;
}
.field { display: flex; flex-direction: column; gap: 6px; }
.field label { font-size: 12px; color: var(--muted); text-transform: uppercase; letter-spacing: 0.6px; }

input[type="number"], input[type="text"] {
  width: 100%;
  background: var(--bg-soft);
  border: 1px solid var(--card-edge);
  color: var(--text);
  border-radius: 10px;
  padding: 12px;
  font: inherit;
  font-size: 18px;
}
input:focus-visible, select:focus-visible, button:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 1px;
}

.btn-swap {
  align-self: end;
  width: 44px;
  height: 44px;
  margin-bottom: 2px;
  border-radius: 50%;
  border: 1px solid var(--card-edge);
  background: var(--bg-soft);
  color: var(--accent);
  font-size: 19px;
  cursor: pointer;
  transition: transform 0.2s, border-color 0.15s;
}
.btn-swap:hover { border-color: var(--accent); }
.btn-swap.spin { transform: rotate(180deg); }

.result-box {
  margin-top: 16px;
  padding: 16px;
  border-radius: 12px;
  background: var(--bg-soft);
  border: 1px solid var(--card-edge);
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}
.result-value {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  font-size: clamp(24px, 7vw, 34px);
  font-weight: 700;
  color: var(--accent);
  word-break: break-all;
}
.result-unit { color: var(--muted); font-size: 15px; }
.btn-copy {
  border: 1px solid var(--card-edge);
  background: transparent;
  color: var(--muted);
  border-radius: 10px;
  padding: 8px 12px;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
}
.btn-copy.ok { color: var(--ok); border-color: var(--ok); }

/* All units table */
.all-table { width: 100%; border-collapse: collapse; margin-top: 6px; }
.all-table th {
  text-align: left;
  font-size: 11px;
  color: var(--muted);
  text-transform: uppercase;
  letter-spacing: 0.6px;
  padding: 6px 8px;
  border-bottom: 1px solid var(--card-edge);
}
.all-table td { padding: 8px; border-bottom: 1px solid rgba(30, 45, 77, 0.55); font-size: 15px; }
.all-table tr:last-child td { border-bottom: none; }
.all-table .num {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  text-align: right;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 190px;
}
.all-table tr.hl td { color: var(--accent); }
.all-table tbody tr { cursor: pointer; }
.all-table tbody tr:hover td { background: rgba(34, 211, 238, 0.05); }
.unit-name { color: var(--muted); font-size: 13px; }
.sym { font-weight: 600; }

h2.section {
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.8px;
  color: var(--muted);
  margin: 4px 0 10px;
}

/* Recents */
.recents { list-style: none; margin: 0; padding: 0; display: flex; flex-direction: column; gap: 8px; }
.recent-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 10px;
  width: 100%;
  text-align: left;
  background: var(--bg-soft);
  border: 1px solid var(--card-edge);
  border-radius: 10px;
  padding: 10px 12px;
  color: var(--text);
  font: inherit;
  cursor: pointer;
}
.recent-item:hover { border-color: var(--accent); }
.recent-item .expr { color: var(--muted); font-size: 13px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.recent-item .val {
  font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
  color: var(--accent);
  white-space: nowrap;
}
.empty { color: var(--muted); font-size: 14px; margin: 4px 0 0; }
.link-btn {
  background: none;
  border: none;
  color: var(--muted);
  text-decoration: underline;
  font: inherit;
  font-size: 13px;
  cursor: pointer;
  padding: 0;
  margin-top: 10px;
}
.link-btn:hover { color: var(--danger); }

footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 0 16px 40px;
  color: var(--muted);
  font-size: 13px;
  text-align: center;
}
footer code { color: var(--accent); font-size: 12px; }

@media (max-width: 420px) {
  .conv-grid { grid-template-columns: 1fr; }
  .btn-swap {
    justify-self: center;
    transform: rotate(90deg);
    margin: -2px 0;
  }
  .btn-swap.spin { transform: rotate(270deg); }
}