:root {
  color-scheme: dark;
  --bg: #161410;
  --bg-raise: #211d17;
  --ink: #f4efe4;
  --muted: #9c9486;
  --line: #3a342b;
  --brass: #e0a64a;
  --brass-dim: #8a6b2c;
  --card: #262119;
  --card-hover: #31291f;
  --danger: #d27a5a;
  --shadow: 0 18px 40px rgba(0, 0, 0, 0.28);
  font-family: "IBM Plex Sans", "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--ink);
}

* {
  box-sizing: border-box;
}

html,
body {
  margin: 0;
  min-height: 100%;
}

body {
  background:
    radial-gradient(1200px 500px at 10% -10%, rgba(224, 166, 74, 0.09), transparent 50%),
    var(--bg);
}

#app {
  width: 100%;
  margin: 0;
  padding: 0 0 72px;
}

.chrome {
  position: sticky;
  top: 0;
  z-index: 40;
  background: rgba(22, 20, 16, 0.96);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(10px);
}

.chrome-inner {
  width: min(1040px, calc(100% - 32px));
  margin: 0 auto;
  padding: 12px 0 14px;
}

.chrome-brand {
  margin: 0 0 10px;
  color: var(--brass);
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.78rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

.section-bar {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 6px;
}

.section-link {
  display: block;
  padding: 13px 8px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--card);
  color: var(--ink);
  text-align: center;
  text-decoration: none;
  font-size: 1.02rem;
  font-weight: 600;
}

.section-link.is-active {
  border-color: var(--brass);
  background: var(--bg-raise);
  color: var(--brass);
}

.page-bar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.page-link {
  padding: 9px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
  color: var(--ink);
  text-decoration: none;
  font-size: 0.98rem;
}

.page-link.is-active {
  border-color: var(--brass);
  color: var(--brass);
  background: var(--bg-raise);
}

.page-body {
  width: min(1040px, calc(100% - 32px));
  margin: 0 auto;
  padding-top: 22px;
}

.hero,
.page-head {
  max-width: 720px;
  margin-bottom: 36px;
}

.brand {
  margin: 0 0 8px;
  color: var(--brass);
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.82rem;
  letter-spacing: 0.16em;
  text-transform: uppercase;
}

h1 {
  margin: 0 0 12px;
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  line-height: 1.15;
  font-weight: 650;
}

h2 {
  margin: 0 0 14px;
  font-size: 0.78rem;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--muted);
}

.lede,
.card-detail,
.result-eq,
.result-sub {
  color: var(--muted);
}

.lede {
  margin: 0;
  font-size: 1.05rem;
  line-height: 1.5;
}

.section + .section {
  margin-top: 36px;
}

.card-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(210px, 1fr));
  gap: 12px;
}

.card,
.panel {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 16px;
}

.card {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 18px 18px 16px;
  color: inherit;
  text-decoration: none;
  min-height: 132px;
  box-shadow: var(--shadow);
  transition: transform 0.15s ease, background 0.15s ease, border-color 0.15s ease;
}

.card:hover,
.card:focus-visible {
  background: var(--card-hover);
  border-color: var(--brass-dim);
  transform: translateY(-2px);
}

.card-kicker {
  font-family: "IBM Plex Mono", monospace;
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--brass);
}

.card strong {
  font-size: 1.2rem;
}

.card-detail {
  margin-top: auto;
  font-size: 0.92rem;
}

.tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin: -8px 0 22px;
}

.tab {
  padding: 8px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--card);
  color: var(--ink);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
}

.tab:hover,
.tab:focus-visible {
  border-color: var(--brass-dim);
}

.tab.is-active {
  border-color: var(--brass);
  background: var(--bg-raise);
  color: var(--brass);
}

.tab-blurb {
  margin: 0 0 8px;
  color: var(--muted);
}

.tab-note {
  margin: 0 0 14px;
  color: var(--brass-dim);
  font-size: 0.9rem;
}

.back {
  display: inline-block;
  margin-bottom: 22px;
  color: var(--brass);
  text-decoration: none;
  font-weight: 500;
}

.back:hover,
.back:focus-visible {
  text-decoration: underline;
}

.panel {
  padding: 22px;
  box-shadow: var(--shadow);
}

.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
  font-size: 0.85rem;
  color: var(--muted);
}

input,
select {
  width: 100%;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-raise);
  color: var(--ink);
  font: 500 1.05rem/1.2 "IBM Plex Mono", monospace;
}

input:focus,
select:focus {
  outline: 2px solid var(--brass);
  outline-offset: 1px;
}

.unit-row,
.grid-2,
.grid-3 {
  display: grid;
  gap: 12px;
  margin-top: 16px;
}

.unit-row {
  grid-template-columns: 1fr auto 1fr;
  align-items: end;
}

.grid-2 {
  grid-template-columns: repeat(2, minmax(0, 1fr));
}

.grid-3 {
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.swap {
  width: 48px;
  height: 48px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-raise);
  color: var(--brass);
  font-size: 1.2rem;
  cursor: pointer;
}

.swap:hover,
.swap:focus-visible {
  border-color: var(--brass-dim);
}

.result {
  margin-top: 22px;
  padding-top: 18px;
  border-top: 1px solid var(--line);
}

.result-top {
  margin: 0 0 12px;
  padding: 12px 14px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-raise);
}

.result-main {
  margin: 0;
  font-size: clamp(1.8rem, 4vw, 2.4rem);
  font-weight: 650;
  letter-spacing: -0.03em;
}

.result-main span {
  font-size: 1rem;
  font-weight: 500;
  color: var(--muted);
}

.result-sub,
.result-eq {
  margin: 8px 0 0;
}

.muted {
  color: var(--muted);
  font-size: 1.2rem;
}

input.is-keypad-target {
  outline: 2px solid var(--brass);
  outline-offset: 1px;
}

.keypad {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
  margin-top: 20px;
}

.keypad-key {
  min-height: 64px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: var(--bg-raise);
  color: var(--ink);
  font: 600 1.35rem/1 "IBM Plex Mono", monospace;
  cursor: pointer;
}

.keypad-key:hover,
.keypad-key:focus-visible {
  border-color: var(--brass-dim);
  background: var(--card-hover);
}

.keypad-key:active {
  transform: translateY(1px);
}

.keypad-action {
  color: var(--brass);
}

.keypad-clear {
  color: #161410;
  background: var(--brass);
  border-color: var(--brass);
}

.keypad-wide {
  grid-column: span 2;
}

@media (max-width: 720px) {
  #app {
    padding-bottom: 8px;
  }

  .chrome-inner,
  .page-body {
    width: min(100% - 16px, 1040px);
  }

  .chrome-brand {
    display: none;
  }

  .chrome-inner {
    padding: 6px 0 8px;
  }

  .section-bar {
    gap: 4px;
  }

  .section-link {
    font-size: 0.88rem;
    padding: 10px 4px;
    border-radius: 8px;
  }

  .page-bar {
    gap: 6px;
    margin-top: 8px;
  }

  .page-link {
    padding: 7px 11px;
    font-size: 0.85rem;
  }

  .page-body {
    padding-top: 8px;
  }

  .tab-blurb,
  .tab-note,
  .result-eq {
    display: none;
  }

  .result-sub {
    display: block;
    font-size: 0.78rem;
  }

  .panel {
    padding: 10px;
    border-radius: 12px;
  }

  .field {
    gap: 4px;
    font-size: 0.72rem;
  }

  input,
  select {
    padding: 8px 10px;
    font-size: 0.95rem;
    border-radius: 8px;
  }

  .unit-row {
    grid-template-columns: 1fr 36px 1fr;
    gap: 6px;
    margin-top: 8px;
    align-items: end;
  }

  .grid-2,
  .grid-3 {
    grid-template-columns: 1fr 1fr;
    gap: 6px;
    margin-top: 8px;
  }

  .swap {
    width: 36px;
    height: 36px;
    font-size: 1rem;
  }

  .keypad {
    gap: 7px;
    margin-top: 10px;
  }

  .keypad-key {
    min-height: 54px;
    border-radius: 10px;
    font-size: 1.2rem;
  }

  .result,
  .result-top {
    margin: 0 0 8px;
    padding: 8px 10px;
    border: 1px solid var(--line);
    border-radius: 8px;
    background: var(--bg-raise);
  }

  .result-main {
    font-size: 1.25rem;
  }

  .result-main span,
  .muted {
    font-size: 0.85rem;
  }
}