:root {
  color-scheme: light dark;

  --bg: #121419;
  --panel: #16181f;
  --panel-2: #1c1f28;
  --line: #2a2e3a;
  --line-soft: #22252f;
  --text: #e7e9ef;
  --muted: #939aad;
  --faint: #6c7385;
  --accent: #b9c0cf;
  --accent-soft: #b9c0cf1f;
  --danger: #ff6b6b;
  --ok: #4ade80;

  /* Concentric: controls are 8px and surfaces pad them by 16px, so the
     surrounding surface must be 8 + 16 = 24px for the corners to nest. */
  --r-control: 8px;
  --pad: 16px;
  --radius: 24px;

  /* Swatch edges must be pure white/black at low opacity, never a tinted
     neutral — a tinted line picks up the surface under it and reads as dirt
     against the color it is supposed to be delineating. */
  --swatch-outline: rgba(255, 255, 255, 0.1);
  --shadow: 0 1px 2px rgba(0, 0, 0, .28), 0 6px 18px -6px rgba(0, 0, 0, .45);

  --ease: cubic-bezier(0.2, 0, 0, 1);
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
}
:root[data-theme="light"] {
  --bg: #f9fafb;
  --panel: #ffffff;
  --panel-2: #f6f7f9;
  --line: #dfe3ea;
  --line-soft: #e9ecf1;
  --text: #14161c;
  --muted: #5d6577;
  --faint: #8b93a5;
  --accent: #3f4653;
  --accent-soft: #3f465314;
  --danger: #d13b3b;
  --ok: #16a34a;
  --swatch-outline: rgba(0, 0, 0, 0.1);
  --shadow: 0 1px 2px rgba(0, 0, 0, .04), 0 6px 16px -8px rgba(0, 0, 0, .10);
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  background: var(--bg);
  color: var(--text);
  font: 14px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
  padding: 80px 20px;
}
.wrap { max-width: 1100px; margin: 0 auto; }

/* ---------- header ---------- */
header {
  display: grid; grid-template-columns: 1fr auto;
  align-items: center; column-gap: 12px; row-gap: 6px;
  margin-bottom: 60px;
}
h1 {
  font-size: 19px; margin: 0; letter-spacing: -0.01em;
  font-family: var(--mono); font-weight: 600; text-wrap: balance;
}
h1 .paren { color: var(--faint); font-weight: 400; }
header p {
  grid-column: 1 / -1;                 /* its own line, under the title */
  margin: 0; color: var(--muted); font-size: 13px; max-width: 68ch;
  text-wrap: pretty;
}
/* Grouped so they centre against each other rather than against the header's
   text baseline — an icon button has no baseline of its own, so `align-items:
   baseline` would synthesize one from its bottom edge and knock it out of line. */
.header-actions {
  grid-column: 2; grid-row: 1;         /* stays beside the title, above the blurb */
  display: flex; align-items: center; gap: 10px;
  margin-left: auto; align-self: center;
}
.theme-btn {
  background: var(--panel); border: 1px solid var(--line);
  color: var(--muted); border-radius: 9px; cursor: pointer;
  width: 34px; height: 34px; flex: none; padding: 0;
  display: grid; place-items: center;
}
.theme-btn:hover { color: var(--text); border-color: var(--faint); }

/* ---------- panels ---------- */
.panel {
  background: var(--panel); border: 1px solid var(--line-soft);
  border-radius: var(--radius); padding: var(--pad);
  box-shadow: var(--shadow);
}
.panel + .panel { margin-top: 18px; }
/* section headings live above their box, not inside it */
.section-head { display: flex; align-items: center; gap: 10px; margin: 40px 2px 12px; }
.section-head h2 {
  margin: 0 auto 0 0; font-size: 14px; font-weight: 600; color: var(--text);
  letter-spacing: -0.005em; text-wrap: balance;
}
.section-head .meta { color: var(--faint); font-family: var(--mono); font-size: 12px; }

/* ---------- color cards ---------- */
.colors { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; align-items: start; position: relative; }
/* sits in the gutter, straddling the seam between the two cards */
.swap-btn {
  position: absolute; left: 50%; top: 50%; transform: translate(-50%, -50%);
  width: 34px; height: 34px; padding: 0; border-radius: 50%; z-index: 2;
  background: var(--panel-2); border: 1px solid var(--line); color: var(--muted);
  display: grid; place-items: center; cursor: pointer;
}
.swap-btn:hover { color: var(--text); border-color: var(--faint); background: var(--panel); }
.swap-btn:active { scale: 0.96; }
.swap-btn svg {
  display: block; fill: none; stroke: currentColor;
  stroke-width: 2; stroke-linecap: round; stroke-linejoin: round;
  transition-property: rotate;
  transition-duration: .3s; transition-timing-function: var(--ease);
}
.color-card {
  background: var(--panel); border: 1px solid var(--line-soft);
  border-radius: var(--radius); padding: var(--pad);
  box-shadow: var(--shadow);
}
.color-card .label {
  font-size: 11px; text-transform: uppercase; letter-spacing: .09em;
  color: var(--faint); font-weight: 600; margin-bottom: 10px;
  display: flex; align-items: center; gap: 8px;
}
.color-card .label .dot {
  width: 8px; height: 8px; border-radius: 50%; background: var(--faint);
}
.color-row { display: flex; gap: 10px; align-items: center; }

.picker-well {
  position: relative; width: 46px; height: 46px; flex: 0 0 46px;
  border-radius: var(--r-control); overflow: hidden;
  border: 1px solid var(--swatch-outline);
  background-image: var(--checker); background-size: 10px 10px;
  background-position: 0 0, 5px 5px;
  background-clip: padding-box;   /* keep the checker out from under the outline */
}
.picker-well .fill { position: absolute; inset: 0; }
.picker-well input[type="color"] {
  position: absolute; inset: 0; width: 100%; height: 100%;
  opacity: 0; cursor: pointer; border: 0; padding: 0;
}

input[type="text"], input[type="number"], select {
  background: var(--panel-2); border: 1px solid var(--line); color: var(--text);
  border-radius: var(--r-control); padding: 8px 10px; font: inherit; width: 100%;
  transition-property: border-color, background-color;
  transition-duration: .15s; transition-timing-function: var(--ease);
}
input[type="text"] { font-family: var(--mono); font-size: 13px; }
input:focus, select:focus, button:focus-visible {
  outline: 2px solid var(--accent); outline-offset: 1px; border-color: transparent;
}
input.invalid { border-color: var(--danger); }
select { cursor: pointer; appearance: none; padding-right: 26px;
  background-image: linear-gradient(45deg, transparent 50%, var(--faint) 50%),
                    linear-gradient(135deg, var(--faint) 50%, transparent 50%);
  background-position: right 12px center, right 7px center;
  background-size: 5px 5px, 5px 5px; background-repeat: no-repeat;
}
select:disabled { opacity: .4; cursor: not-allowed; }

/* alpha sits inline after the value field, only as wide as it needs to be */
.color-row input[type="text"] { flex: 1 1 auto; width: auto; min-width: 0; }
.alpha-field { display: flex; align-items: center; gap: 6px; flex: none; }
.alpha-field label { font-family: var(--mono); font-size: 14px; color: var(--faint); cursor: default; }
.alpha-field input[type="number"] {
  width: 76px; padding: 8px 6px 8px 8px; text-align: right;
  font-family: var(--mono); font-size: 13px;
}

.chip-row { display: flex; gap: 6px; margin-top: 10px; flex-wrap: wrap; }
.chip {
  background: var(--panel-2); border: 1px solid var(--line); color: var(--muted);
  border-radius: 999px; padding: 3px 9px; font-size: 11px; cursor: pointer;
  font-family: var(--mono);
}
.chip:hover { color: var(--text); border-color: var(--faint); }
.chip.active { background: var(--accent-soft); border-color: var(--accent); color: var(--accent); }
.seg { display: flex; gap: 5px; text-transform: none; letter-spacing: 0; }

/* ---------- settings ---------- */
.settings { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; }
.field { display: flex; flex-direction: column; gap: 5px; }
.field > span { font-size: 11px; color: var(--muted); font-weight: 400; }

button.btn {
  background: var(--panel-2); border: 1px solid var(--line); color: var(--text);
  border-radius: 8px; padding: 7px 12px; cursor: pointer; font: inherit; font-size: 13px;
}
button.btn:hover { border-color: var(--faint); }
button.btn.ghost { background: transparent; color: var(--muted); }

/* ---------- result ---------- */
.pct-field {
  display: flex; align-items: center; gap: 6px;
  text-transform: none; letter-spacing: 0; font-family: var(--mono); font-size: 12px;
}
.pct-field input[type="number"] {
  width: 66px; padding: 4px 6px 4px 8px; font-size: 13px; text-align: right;
  font-family: var(--mono); font-weight: 600; color: var(--text);
}

.result { display: grid; grid-template-columns: 132px 1fr; gap: 18px; align-items: stretch; }
.result-swatch {
  border-radius: var(--r-control); border: 1px solid var(--swatch-outline); min-height: 122px;
  background-image: var(--checker); background-size: 14px 14px; background-position: 0 0, 7px 7px;
  background-clip: padding-box;   /* keep the checker out from under the outline */
  position: relative; overflow: hidden;
  display: block; width: 100%; padding: 0; cursor: pointer; font: inherit;
}
.result-swatch:hover { border-color: var(--muted); }
.result-swatch .fill { position: absolute; inset: 0; }

.value-row { display: flex; align-items: center; gap: 8px; min-width: 0; }
.value-row .big-value { min-width: 0; }
.copy-btn {
  flex: none; background: transparent; border: 1px solid transparent; color: var(--faint);
  border-radius: 7px; width: 28px; height: 28px; padding: 0; cursor: pointer;
  display: grid; place-items: center;
}
.copy-btn:hover { color: var(--text); background: var(--panel); border-color: var(--line); }
.copy-btn svg {
  display: block; fill: none; stroke: currentColor;
  stroke-width: 2; stroke-linecap: round; stroke-linejoin: round;
}
.copy-btn.copied { color: var(--ok); }
.result-main { display: flex; flex-direction: column; gap: 20px; min-width: 0; }
.big-value {
  font-family: var(--mono); font-size: clamp(20px, 4vw, 32px); font-weight: 600;
  letter-spacing: -0.01em; word-break: break-all; line-height: 1.2;
}
/* expression sits on one row with the mix % — the box hugs its text */
.expr-row { display: flex; align-items: center; gap: 12px; flex-wrap: wrap; }
.expr {
  font-family: var(--mono); font-size: 12.5px; color: var(--text);
  background: var(--panel-2); border: 1px solid var(--line-soft);
  border-radius: var(--r-control); padding: 5px 5px 5px 10px; word-break: break-all;
  display: flex; align-items: center; gap: 8px; min-height: 36px;
  flex: 0 1 auto; min-width: 0;
}
/* keeps the mix field on the right edge even when the expression wraps it to its own line */
.expr-row .pct-field { margin-left: auto; }
.badges { display: flex; gap: 6px; flex-wrap: wrap; }
.badges:empty { display: none; }
.badge {
  font-size: 11px; padding: 2px 8px; border-radius: 999px;
  border: 1px solid var(--line); color: var(--muted); font-family: var(--mono);
}
.badge.warn { color: #f5a524; border-color: #f5a52455; background: #f5a52411; }
.badge.err { color: var(--danger); border-color: color-mix(in srgb, var(--danger), transparent 60%); }

/* ---------- ramp ---------- */
.ramp {
  height: 26px; border-radius: var(--r-control); border: 1px solid var(--swatch-outline);
  background-image: var(--checker); background-size: 10px 10px; background-position: 0 0, 5px 5px;
  background-clip: padding-box;   /* keep the checker out from under the outline */
  position: relative; overflow: hidden; margin-bottom: 16px;
}
.ramp .fill { position: absolute; inset: 0; }

/* one swatch per column, single row — --cols is set from the step count */
.steps { display: grid; gap: 8px; grid-template-columns: repeat(var(--cols, 11), minmax(0, 1fr)); }
.steps.compact { gap: 2px; }
.step {
  background: none; border: 0; padding: 0; cursor: pointer; text-align: left;
  display: flex; flex-direction: column; gap: 5px; font: inherit; color: inherit;
  border-radius: 8px;
}
.step .chip-box {
  height: 62px; border-radius: var(--r-control); border: 1px solid var(--swatch-outline);
  background-image: var(--checker); background-size: 10px 10px; background-position: 0 0, 5px 5px;
  background-clip: padding-box;   /* keep the checker out from under the outline */
  position: relative; overflow: hidden;
}
.step .chip-box .fill { position: absolute; inset: 0; }
.step:hover .chip-box { border-color: var(--muted); }
.step .pct { font-family: var(--mono); font-size: 11px; color: var(--muted); }
.step .val { font-family: var(--mono); font-size: 10.5px; color: var(--faint); word-break: break-all; line-height: 1.35; }
.steps.compact .chip-box { height: 54px; border-radius: 3px; border-width: 1px; }
.steps.compact .pct, .steps.compact .val { display: none; }

/* ---------- code ---------- */
pre.code {
  margin: 0; font-family: var(--mono); font-size: 12px; line-height: 1.7;
  background: var(--panel-2); border: 1px solid var(--line-soft); border-radius: var(--r-control);
  padding: 12px 14px; overflow-x: auto; color: var(--text);
  max-height: 320px; overflow-y: auto;
}
pre.code .c { color: var(--faint); }
pre.code .p { color: var(--accent); }

.hint { color: var(--faint); font-size: 12px; margin: 10px 0 0; }
.result-main .hint { margin: 0; }   /* spacing comes from the column gap instead */
.hint kbd {
  font-family: var(--mono); font-size: 11px; border: 1px solid var(--line);
  border-radius: 4px; padding: 0 4px; background: var(--panel-2);
}

.banner {
  border: 1px solid color-mix(in srgb, var(--danger), transparent 60%);
  background: color-mix(in srgb, var(--danger), transparent 92%);
  color: var(--danger); border-radius: var(--r-control); padding: 10px 12px; font-size: 13px;
  margin-bottom: 14px;
}

#toast {
  position: fixed; left: 50%; bottom: 28px; transform: translate(-50%, 14px);
  background: var(--text); color: var(--bg); font-size: 13px; font-weight: 500;
  padding: 8px 14px; border-radius: 999px; opacity: 0; pointer-events: none;
  transition: opacity .18s ease, transform .18s ease; z-index: 20;
  font-family: var(--mono);
}
#toast.show { opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 720px) {
  .colors { grid-template-columns: 1fr; }
  /* cards stack, so the arrows should point up/down */
  .swap-btn { transform: translate(-50%, -50%) rotate(90deg); }

  .result { grid-template-columns: 1fr; }
  .result-swatch { min-height: 90px; }
  /* too narrow for one row — let the swatches wrap instead of hairlining */
  .steps { grid-template-columns: repeat(auto-fit, minmax(84px, 1fr)); }
  .steps.compact { grid-template-columns: repeat(auto-fit, minmax(14px, 1fr)); }
}

/* ---------- page nav ---------- */
.nav { display: flex; gap: 4px; align-items: center; }
.nav-link {
  font-size: 12.5px; color: var(--muted); text-decoration: none;
  display: inline-flex; align-items: center; height: 34px; padding: 0 12px;
  border-radius: 9px; border: 1px solid transparent;   /* matches .theme-btn */
}
.nav-link:hover { color: var(--text); background: var(--panel); }
.nav-link[aria-current="page"] { color: var(--text); background: var(--panel); border-color: var(--line); }

/* ---------- scale page ---------- */
.single-card { margin-bottom: 4px; }
.name-field { display: flex; align-items: center; gap: 6px; flex: none; }
.name-field label {
  font-size: 11px; color: var(--faint); text-transform: uppercase;
  letter-spacing: .07em; font-weight: 600;
}
.name-field input[type="text"] { width: 168px; flex: none; }

/* the base color the user actually picked, sitting mid-scale */
.step.base .chip-box { outline: 2px solid var(--accent); outline-offset: 2px; }
.step.base .pct { color: var(--accent); font-weight: 600; }
.steps.tokens .pct { font-size: 11.5px; }

/* =============================================================================
   INTERACTION POLISH
   ============================================================================= */

/* --- Contextual icon animation -------------------------------------------
   Both icons stay in the DOM stacked in the same grid cell and cross-fade with
   scale + blur, so the swap has an exit as well as an enter. Toggling
   `display` gave a hard cut and no exit at all. */
.theme-btn svg,
.copy-btn svg {
  grid-area: 1 / 1;
  opacity: 0; scale: 0.25; filter: blur(4px);
  transition-property: opacity, scale, filter;
  transition-duration: .25s;
  transition-timing-function: var(--ease);
}
:root[data-theme="dark"] .theme-btn .i-sun,
:root[data-theme="light"] .theme-btn .i-moon,
.copy-btn .i-copy,
.copy-btn.copied .i-check {
  opacity: 1; scale: 1; filter: blur(0px);
}
.copy-btn.copied .i-copy { opacity: 0; scale: 0.25; filter: blur(4px); }

/* --- Interruptible hover / press ----------------------------------------- */
.theme-btn, .swap-btn, .copy-btn, .nav-link, .chip, button.btn,
.step .chip-box, .result-swatch {
  transition-property: color, background-color, border-color, box-shadow, scale;
  transition-duration: .15s;
  transition-timing-function: var(--ease);
}

/* Tactile press. 0.96 is the floor — anything smaller reads as exaggerated. */
.theme-btn:active, .copy-btn:active, .nav-link:active,
.chip:active, button.btn:active, .step:active, .result-swatch:active {
  scale: 0.96;
}
/* .result-swatch already lists scale above — only .step needs its own rule */
.step {
  transition-property: scale; transition-duration: .15s;
  transition-timing-function: var(--ease);
}

/* --- Minimum 40x40 hit area ----------------------------------------------
   The visible controls are deliberately small; the pseudo-element grows only
   the touch target. Widths use max() so nothing spills into a neighbour's
   target — every chip is already wider than 40px, so only height grows. */
/* .swap-btn is deliberately absolute already — don't reset it to relative */
.theme-btn, .copy-btn, .nav-link, .chip, button.btn { position: relative; }
.theme-btn::after, .swap-btn::after, .copy-btn::after,
.nav-link::after, .chip::after, button.btn::after {
  content: ""; position: absolute; left: 50%; top: 50%;
  width: max(100%, 40px); height: max(100%, 40px);
  transform: translate(-50%, -50%);
}

/* --- Numerals ------------------------------------------------------------
   Values rewrite on every keystroke; tabular figures keep them from jittering
   even if the monospace stack falls back to a proportional face. */
.big-value, .step .pct, .step .val, .badge, .section-head .meta,
.expr, pre.code, input[type="number"] {
  font-variant-numeric: tabular-nums;
}

.hint { text-wrap: pretty; }

/* --- Staged enter --------------------------------------------------------
   Split by section and staggered rather than fading the page in as one block.
   `.ready` is set after the first paint so the icon cross-fades above don't
   play their enter animation on load. */
@media (prefers-reduced-motion: no-preference) {
  :root.ready .wrap > * { animation: section-enter .45s var(--ease) backwards; }
  :root.ready .wrap > *:nth-child(2)  { animation-delay: .04s; }
  :root.ready .wrap > *:nth-child(3)  { animation-delay: .08s; }
  :root.ready .wrap > *:nth-child(4)  { animation-delay: .12s; }
  :root.ready .wrap > *:nth-child(5)  { animation-delay: .16s; }
  :root.ready .wrap > *:nth-child(6)  { animation-delay: .20s; }
  :root.ready .wrap > *:nth-child(7)  { animation-delay: .24s; }
  :root.ready .wrap > *:nth-child(8)  { animation-delay: .28s; }
  :root.ready .wrap > *:nth-child(n+9) { animation-delay: .32s; }
}
@keyframes section-enter {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: none; }
}
:root:not(.ready) .theme-btn svg,
:root:not(.ready) .copy-btn svg { transition: none; }