/* ==========================================================================
   Rubik's Trainer — design system
   Light, airy, generous whitespace. Content stretches to 90% of the viewport
   on desktop and goes edge-to-edge (with gutters) on phones.
   ========================================================================== */

:root {
  /* Cube colours double as the accent palette — one per CFOP phase. */
  --cube-white: #f7f7f7;
  --cube-yellow: #ffd500;
  --cube-green: #009b48;
  --cube-blue: #0045ad;
  --cube-red: #b71234;
  --cube-orange: #ff5800;

  --phase-cross: #0045ad;
  --phase-f2l: #009b48;
  --phase-oll: #f0a500;
  --phase-pll: #b71234;

  /* Neutrals — cool, low contrast, plenty of air. */
  --ink-900: #14161a;
  --ink-700: #363b44;
  --ink-500: #5f6773;
  --ink-400: #868e9c;
  --ink-300: #b6bdc8;
  --ink-200: #dde1e8;
  --ink-100: #eceff4;
  --ink-050: #f5f7fa;
  --paper: #ffffff;
  --canvas: #f7f9fc;

  --accent: #3d5afe;
  --accent-soft: #eaeeff;
  --success: #12855c;
  --success-soft: #e4f5ee;
  --warn: #b8760a;
  --warn-soft: #fdf2dd;
  --danger: #c62b3f;
  --danger-soft: #fdeaec;

  --radius-sm: 8px;
  --radius: 14px;
  --radius-lg: 20px;
  --radius-pill: 999px;

  --shadow-xs: 0 1px 2px rgba(20, 22, 26, 0.05);
  --shadow-sm: 0 2px 8px rgba(20, 22, 26, 0.06);
  --shadow-md: 0 8px 28px rgba(20, 22, 26, 0.08);
  --shadow-lg: 0 20px 60px rgba(20, 22, 26, 0.12);

  --space-1: 4px;
  --space-2: 8px;
  --space-3: 12px;
  --space-4: 16px;
  --space-5: 24px;
  --space-6: 32px;
  --space-7: 48px;
  --space-8: 64px;

  --font-sans: system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue",
    Arial, "Noto Sans", sans-serif;
  --font-mono: ui-monospace, "SF Mono", "JetBrains Mono", "Fira Code",
    "Cascadia Code", Menlo, Consolas, monospace;

  --content-max: 90vw;
  --content-cap: 1560px;
  --header-h: 64px;

  --ease: cubic-bezier(0.22, 0.61, 0.36, 1);
  --dur-fast: 120ms;
  --dur: 220ms;
  --dur-slow: 420ms;
}

/* --------------------------------------------------------------------- */
/* Reset                                                                  */
/* --------------------------------------------------------------------- */

*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.55;
  color: var(--ink-700);
  background: var(--canvas);
  background-image:
    radial-gradient(1100px 500px at 12% -8%, rgba(61, 90, 254, 0.06), transparent 62%),
    radial-gradient(900px 460px at 96% 0%, rgba(0, 155, 72, 0.05), transparent 60%);
  background-attachment: fixed;
  min-height: 100vh;
  -webkit-font-smoothing: antialiased;
}

h1, h2, h3, h4, h5 {
  margin: 0 0 var(--space-3);
  color: var(--ink-900);
  font-weight: 620;
  line-height: 1.2;
  letter-spacing: -0.018em;
}

h1 { font-size: clamp(1.6rem, 1.15rem + 1.5vw, 2.35rem); }
h2 { font-size: clamp(1.25rem, 1.05rem + 0.8vw, 1.6rem); }
h3 { font-size: 1.12rem; }
h4 { font-size: 1rem; }

p { margin: 0 0 var(--space-4); }
p:last-child { margin-bottom: 0; }

a {
  color: var(--accent);
  text-decoration: none;
  transition: color var(--dur-fast) var(--ease);
}
a:hover { color: #2a41d8; text-decoration: underline; }

img, svg, canvas { max-width: 100%; }
img { height: auto; display: block; }

code, kbd, pre { font-family: var(--font-mono); }

hr {
  border: 0;
  border-top: 1px solid var(--ink-200);
  margin: var(--space-6) 0;
}

:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
  border-radius: 4px;
}

/* The `hidden` attribute must always win.
   The UA rule is `[hidden] { display: none }` — a bare element selector, so
   any class that sets `display` outranks it and silently makes `el.hidden =
   true` do nothing. That shipped once already: the dashboard's radar tooltip
   used `display: flex` and never went away when the pointer left the dot. */
[hidden] { display: none !important; }

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

.skip-link {
  position: absolute;
  left: var(--space-4);
  top: -60px;
  z-index: 200;
  background: var(--paper);
  padding: var(--space-2) var(--space-4);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-md);
  transition: top var(--dur) var(--ease);
}
.skip-link:focus { top: var(--space-3); }

/* --------------------------------------------------------------------- */
/* Layout                                                                 */
/* --------------------------------------------------------------------- */

.shell {
  width: min(var(--content-max), var(--content-cap));
  margin-inline: auto;
  padding-inline: var(--space-4);
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 60;
  background: rgba(255, 255, 255, 0.82);
  backdrop-filter: saturate(180%) blur(14px);
  -webkit-backdrop-filter: saturate(180%) blur(14px);
  border-bottom: 1px solid var(--ink-200);
}

.site-header__inner {
  display: flex;
  align-items: center;
  gap: var(--space-5);
  min-height: var(--header-h);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-weight: 680;
  color: var(--ink-900);
  letter-spacing: -0.02em;
  white-space: nowrap;
}
.brand:hover { text-decoration: none; color: var(--ink-900); }

.brand__mark {
  width: 30px;
  height: 30px;
  border-radius: 7px;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  grid-template-rows: repeat(3, 1fr);
  gap: 1.5px;
  padding: 2.5px;
  background: var(--ink-900);
  box-shadow: var(--shadow-xs);
}
.brand__mark i { border-radius: 1.5px; display: block; }

.brand__name { font-size: 1.02rem; }
.brand__name small {
  display: block;
  font-size: 0.68rem;
  font-weight: 500;
  color: var(--ink-400);
  letter-spacing: 0;
}

.nav {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  margin-left: auto;
  flex-wrap: wrap;
}

.nav__link {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-2) var(--space-3);
  border-radius: var(--radius-pill);
  color: var(--ink-500);
  font-size: 0.92rem;
  font-weight: 550;
  transition: background var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
}
.nav__link:hover {
  background: var(--ink-100);
  color: var(--ink-900);
  text-decoration: none;
}
.nav__link[aria-current="page"] {
  background: var(--accent-soft);
  color: #2a41d8;
}

.nav-toggle {
  display: none;
  margin-left: auto;
  background: none;
  border: 1px solid var(--ink-200);
  border-radius: var(--radius-sm);
  padding: var(--space-2) var(--space-3);
  color: var(--ink-700);
  cursor: pointer;
}

.profile-chip {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  padding: var(--space-1) var(--space-3) var(--space-1) var(--space-1);
  border: 1px solid var(--ink-200);
  border-radius: var(--radius-pill);
  background: var(--paper);
  color: var(--ink-700);
  font-size: 0.85rem;
  font-weight: 560;
}
.profile-chip:hover { text-decoration: none; border-color: var(--ink-300); }
.profile-chip__avatar {
  width: 24px;
  height: 24px;
  border-radius: 50%;
  display: grid;
  place-items: center;
  background: var(--accent-soft);
  color: #2a41d8;
  font-size: 0.72rem;
  font-weight: 700;
}

main { padding-block: var(--space-6) var(--space-8); }

.page-head {
  display: flex;
  flex-wrap: wrap;
  align-items: flex-end;
  justify-content: space-between;
  gap: var(--space-4);
  margin-bottom: var(--space-6);
}
.page-head__text { max-width: 68ch; }
.page-head__lede {
  color: var(--ink-500);
  font-size: 1.02rem;
  margin: 0;
}
.page-head__actions {
  display: flex;
  gap: var(--space-2);
  flex-wrap: wrap;
}

.stack   { display: flex; flex-direction: column; gap: var(--space-5); }
.stack-4 { display: flex; flex-direction: column; gap: var(--space-4); }
.stack-3 { display: flex; flex-direction: column; gap: var(--space-3); }
.row {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  flex-wrap: wrap;
}
.row--between { justify-content: space-between; }
.row--end { justify-content: flex-end; }
.grow { flex: 1 1 auto; }

.grid { display: grid; gap: var(--space-5); }
.grid--2 { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
.grid--3 { grid-template-columns: repeat(auto-fit, minmax(260px, 1fr)); }
.grid--4 { grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); }
.grid--split { grid-template-columns: minmax(0, 1.35fr) minmax(0, 1fr); }

@media (max-width: 900px) {
  /* minmax(0, 1fr), not 1fr: a grid item's automatic minimum size is its
     content's min-content width, so a wide table inside a track forces the
     whole page wider than the viewport and the .table-wrap scroller never
     engages. Measured: a 527px phase table widened a 375px page to 593px. */
  .grid--split { grid-template-columns: minmax(0, 1fr); }
}

/* --------------------------------------------------------------------- */
/* Surfaces                                                               */
/* --------------------------------------------------------------------- */

.card {
  background: var(--paper);
  border: 1px solid var(--ink-200);
  border-radius: var(--radius);
  box-shadow: var(--shadow-xs);
  padding: var(--space-5);
}
.card--flush { padding: 0; overflow: hidden; }
.card--quiet { background: var(--ink-050); box-shadow: none; }
.card__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
  margin-bottom: var(--space-4);
}
.card__title { margin: 0; font-size: 1.02rem; font-weight: 620; color: var(--ink-900); }
.card__hint { color: var(--ink-400); font-size: 0.85rem; }

.panel {
  background: var(--paper);
  border: 1px solid var(--ink-200);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: var(--space-6);
}

/* --------------------------------------------------------------------- */
/* Buttons                                                                */
/* --------------------------------------------------------------------- */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  /* min-height, not more padding: padding-derived sizing measured 37px for
     .btn and 30px for .btn--sm, both under the ~40px touch floor, and three
     page stylesheets had each grown their own override. A floor here fixes
     every button at once without changing how any of them look on desktop. */
  min-height: 40px;
  padding: 9px 16px;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  background: var(--ink-900);
  color: #fff;
  font: inherit;
  font-size: 0.92rem;
  font-weight: 580;
  line-height: 1.2;
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  transition: transform var(--dur-fast) var(--ease),
    background var(--dur-fast) var(--ease), box-shadow var(--dur-fast) var(--ease),
    border-color var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
}
.btn:hover { background: #22262d; color: #fff; text-decoration: none; box-shadow: var(--shadow-sm); }
.btn:active { transform: translateY(1px); }
.btn[disabled], .btn.is-disabled {
  opacity: 0.45;
  pointer-events: none;
}

.btn--primary { background: var(--accent); }
.btn--primary:hover { background: #2a41d8; }

.btn--ghost {
  background: var(--paper);
  color: var(--ink-700);
  border-color: var(--ink-200);
}
.btn--ghost:hover { background: var(--ink-050); color: var(--ink-900); border-color: var(--ink-300); }

.btn--subtle {
  background: var(--ink-100);
  color: var(--ink-700);
}
.btn--subtle:hover { background: var(--ink-200); color: var(--ink-900); }

.btn--danger { background: var(--danger); }
.btn--danger:hover { background: #a92132; }

.btn--sm { min-height: 36px; padding: 6px 12px; font-size: 0.84rem; }
.btn--lg { padding: 13px 26px; font-size: 1rem; }
.btn--block { width: 100%; }
.btn--icon { padding: 8px; width: 40px; height: 40px; min-height: 40px; border-radius: 50%; }

.btn-group {
  display: inline-flex;
  background: var(--ink-100);
  border-radius: var(--radius-pill);
  padding: 3px;
  gap: 2px;
}
.btn-group button, .btn-group a {
  border: 0;
  background: transparent;
  border-radius: var(--radius-pill);
  padding: 6px 14px;
  font: inherit;
  font-size: 0.86rem;
  font-weight: 560;
  color: var(--ink-500);
  cursor: pointer;
  transition: background var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
}
.btn-group button:hover, .btn-group a:hover { color: var(--ink-900); text-decoration: none; }
.btn-group [aria-pressed="true"], .btn-group .is-active {
  background: var(--paper);
  color: var(--ink-900);
  box-shadow: var(--shadow-xs);
}

/* --------------------------------------------------------------------- */
/* Forms                                                                  */
/* --------------------------------------------------------------------- */

label { font-size: 0.88rem; font-weight: 560; color: var(--ink-700); }

.field { display: flex; flex-direction: column; gap: var(--space-2); }
.field__hint { font-size: 0.8rem; color: var(--ink-400); font-weight: 400; }

input[type="text"], input[type="number"], input[type="search"], input[type="url"],
select, textarea {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--ink-200);
  border-radius: var(--radius-sm);
  background: var(--paper);
  color: var(--ink-900);
  font: inherit;
  font-size: 0.94rem;
  transition: border-color var(--dur-fast) var(--ease), box-shadow var(--dur-fast) var(--ease);
}
input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}
textarea { min-height: 96px; resize: vertical; font-family: var(--font-mono); font-size: 0.88rem; }

input[type="range"] { width: 100%; accent-color: var(--accent); }
input[type="checkbox"], input[type="radio"] { accent-color: var(--accent); width: 16px; height: 16px; }

.switch { display: inline-flex; align-items: center; gap: var(--space-2); cursor: pointer; }

/* --------------------------------------------------------------------- */
/* Badges, pills, meters                                                  */
/* --------------------------------------------------------------------- */

.badge {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 2px 10px;
  border-radius: var(--radius-pill);
  font-size: 0.76rem;
  font-weight: 620;
  letter-spacing: 0.01em;
  background: var(--ink-100);
  color: var(--ink-600, var(--ink-500));
  white-space: nowrap;
}
.badge--ok { background: var(--success-soft); color: var(--success); }
.badge--warn { background: var(--warn-soft); color: var(--warn); }
.badge--bad { background: var(--danger-soft); color: var(--danger); }
.badge--accent { background: var(--accent-soft); color: #2a41d8; }
.badge--phase { color: #fff; }
.badge--f2l { background: var(--phase-f2l); color: #fff; }
.badge--oll { background: var(--phase-oll); color: #4a3200; }
.badge--pll { background: var(--phase-pll); color: #fff; }
.badge--cross { background: var(--phase-cross); color: #fff; }

.meter {
  --meter-value: 0;
  --meter-color: var(--accent);
  height: 6px;
  border-radius: var(--radius-pill);
  background: var(--ink-100);
  overflow: hidden;
}
.meter > i {
  display: block;
  height: 100%;
  width: calc(var(--meter-value) * 1%);
  background: var(--meter-color);
  border-radius: inherit;
  transition: width var(--dur-slow) var(--ease);
}

.stat {
  display: flex;
  flex-direction: column;
  gap: 2px;
}
.stat__label {
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-400);
  font-weight: 620;
}
.stat__value {
  font-size: clamp(1.5rem, 1.2rem + 1vw, 2rem);
  font-weight: 660;
  color: var(--ink-900);
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
}
.stat__delta { font-size: 0.82rem; color: var(--ink-400); }

.alg {
  font-family: var(--font-mono);
  font-size: 0.92rem;
  color: var(--ink-900);
  background: var(--ink-050);
  border: 1px solid var(--ink-200);
  border-radius: var(--radius-sm);
  padding: 6px 10px;
  display: inline-block;
  word-spacing: 0.12em;
  overflow-wrap: anywhere;
}
.alg--primary { background: var(--accent-soft); border-color: #cfd8ff; }

/* --------------------------------------------------------------------- */
/* Tables                                                                 */
/* --------------------------------------------------------------------- */

.table-wrap { overflow-x: auto; -webkit-overflow-scrolling: touch; }

table.data {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
}
table.data th, table.data td {
  padding: var(--space-3) var(--space-4);
  text-align: left;
  border-bottom: 1px solid var(--ink-100);
  vertical-align: middle;
}
table.data th {
  font-size: 0.76rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--ink-400);
  font-weight: 660;
  white-space: nowrap;
}
table.data tbody tr:hover { background: var(--ink-050); }
table.data td.num { text-align: right; font-variant-numeric: tabular-nums; }

/* --------------------------------------------------------------------- */
/* Flash messages                                                         */
/* --------------------------------------------------------------------- */

.flashes {
  position: fixed;
  top: calc(var(--header-h) + var(--space-3));
  right: var(--space-4);
  z-index: 120;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  max-width: min(420px, 90vw);
}
.flash {
  display: flex;
  align-items: flex-start;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius);
  background: var(--paper);
  border: 1px solid var(--ink-200);
  box-shadow: var(--shadow-md);
  font-size: 0.9rem;
  animation: flash-in var(--dur) var(--ease);
}
.flash--success { border-left: 3px solid var(--success); }
.flash--error { border-left: 3px solid var(--danger); }
.flash--warning { border-left: 3px solid var(--warn); }
.flash button {
  background: none;
  border: 0;
  color: var(--ink-400);
  cursor: pointer;
  font-size: 1.1rem;
  line-height: 1;
  padding: 0;
}

@keyframes flash-in {
  from { opacity: 0; transform: translateY(-8px); }
  to { opacity: 1; transform: none; }
}

/* --------------------------------------------------------------------- */
/* Empty states                                                           */
/* --------------------------------------------------------------------- */

.empty {
  text-align: center;
  padding: var(--space-7) var(--space-5);
  color: var(--ink-500);
  border: 1px dashed var(--ink-200);
  border-radius: var(--radius);
  background: var(--paper);
}
.empty h3, .empty h4 { color: var(--ink-700); }

/* --------------------------------------------------------------------- */
/* Footer                                                                 */
/* --------------------------------------------------------------------- */

.site-footer {
  border-top: 1px solid var(--ink-200);
  padding-block: var(--space-5);
  color: var(--ink-400);
  font-size: 0.84rem;
}
.site-footer a { color: var(--ink-500); }

/* --------------------------------------------------------------------- */
/* Responsive                                                             */
/* --------------------------------------------------------------------- */

@media (max-width: 860px) {
  :root { --content-max: 100vw; }

  .nav-toggle { display: inline-flex; }
  .nav {
    display: none;
    position: absolute;
    top: var(--header-h);
    left: 0;
    right: 0;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    background: var(--paper);
    border-bottom: 1px solid var(--ink-200);
    box-shadow: var(--shadow-md);
    padding: var(--space-2);
  }
  .nav.is-open { display: flex; }
  .nav__link { border-radius: var(--radius-sm); padding: var(--space-3); }

  .site-header__inner { position: relative; }
  main { padding-block: var(--space-5) var(--space-7); }
  .panel { padding: var(--space-4); }
  .flashes { left: var(--space-3); right: var(--space-3); max-width: none; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

@media print {
  .site-header, .site-footer, .page-head__actions, .flashes { display: none !important; }
  body { background: #fff; }
  .card, .panel { box-shadow: none; border-color: #ccc; }
}

/* --------------------------------------------------------------------- */
/* Shared macro components (partials/_macros.html)                        */
/* --------------------------------------------------------------------- */

.score-meter {
  display: inline-flex;
  align-items: center;
  gap: var(--space-2);
  min-width: 92px;
}
.score-meter .meter { flex: 1 1 auto; min-width: 48px; }
.score-meter b {
  font-size: 0.82rem;
  font-variant-numeric: tabular-nums;
  color: var(--ink-500);
  font-weight: 640;
}

.star-btn {
  display: inline-grid;
  place-items: center;
  width: 32px;
  height: 32px;
  padding: 0;
  border: 0;
  border-radius: 50%;
  background: transparent;
  color: var(--ink-300);
  cursor: pointer;
  transition: color var(--dur-fast) var(--ease), background var(--dur-fast) var(--ease),
    transform var(--dur-fast) var(--ease);
}
.star-btn:hover { background: var(--ink-100); color: var(--ink-400); }
.star-btn[aria-pressed="true"] { color: #f0a500; }
.star-btn[aria-pressed="true"] svg { fill: #ffc93c; }
.star-btn:active { transform: scale(0.9); }
.star-btn svg { fill: none; }

.stat-tile { display: flex; align-items: center; }

.alg[role="button"] { cursor: pointer; }
.alg[role="button"]:hover { border-color: var(--ink-300); }

/* On a touch device the small variant gets the full floor too. Pointer-coarse
   rather than a width query: a stylus or a touchscreen laptop needs the
   bigger target at any viewport size. */
@media (pointer: coarse) {
  .btn--sm { min-height: 40px; }
  .nav-toggle { min-height: 40px; min-width: 40px; }
}