/*
 * coolmaths — shared styles for the home page and every game.
 * Colours are tokens so the whole site follows the light/dark theme:
 * the OS preference by default, or the header toggle (html[data-theme]).
 */

:root {
  color-scheme: light;
  --bg: #ffffff;
  --card: #ffffff;
  --surface: #f5f6f8;
  --surface-2: #eceef2;
  --text: #0f1115;
  --muted: #5d6472;
  --border: #e4e7ec;
  --border-strong: #cdd2da;
  --accent: #5b4ee8;
  --accent-hover: #4a3dd6;
  --accent-soft: rgba(91, 78, 232, 0.10);
  --accent-text: #ffffff;
  --good: #15803d;
  --bad: #c2362b;
  --focus: rgba(91, 78, 232, 0.45);
  --shadow: 0 1px 2px rgba(16, 18, 24, 0.05), 0 4px 16px rgba(16, 18, 24, 0.06);
  --shadow-hover: 0 2px 4px rgba(16, 18, 24, 0.06), 0 12px 32px rgba(16, 18, 24, 0.10);

  /* game art */
  --stage: #f3f5f8;
  --ink: #1f2430;
  --board-a: #e9edf3;
  --board-b: #d5dce7;
  --highlight: rgba(255, 214, 10, 0.35);

  --radius: 14px;
  --font: ui-sans-serif, system-ui, -apple-system, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --mono: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    color-scheme: dark;
    --bg: #0b0c0f;
    --card: #14161b;
    --surface: #16181e;
    --surface-2: #1f222a;
    --text: #eceef2;
    --muted: #9aa1ad;
    --border: #252932;
    --border-strong: #363b46;
    --accent: #8f86ff;
    --accent-hover: #a39cff;
    --accent-soft: rgba(143, 134, 255, 0.14);
    --accent-text: #0b0c0f;
    --good: #4ade80;
    --bad: #f87171;
    --focus: rgba(143, 134, 255, 0.55);
    --shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-hover: 0 2px 4px rgba(0, 0, 0, 0.5), 0 12px 32px rgba(0, 0, 0, 0.45);
    --stage: #15171d;
    --ink: #c9cfda;
    --board-a: #262b35;
    --board-b: #1b1f27;
    --highlight: rgba(255, 214, 10, 0.22);
  }
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0b0c0f;
  --card: #14161b;
  --surface: #16181e;
  --surface-2: #1f222a;
  --text: #eceef2;
  --muted: #9aa1ad;
  --border: #252932;
  --border-strong: #363b46;
  --accent: #8f86ff;
  --accent-hover: #a39cff;
  --accent-soft: rgba(143, 134, 255, 0.14);
  --accent-text: #0b0c0f;
  --good: #4ade80;
  --bad: #f87171;
  --focus: rgba(143, 134, 255, 0.55);
  --shadow: 0 1px 2px rgba(0, 0, 0, 0.4);
  --shadow-hover: 0 2px 4px rgba(0, 0, 0, 0.5), 0 12px 32px rgba(0, 0, 0, 0.45);
  --stage: #15171d;
  --ink: #c9cfda;
  --board-a: #262b35;
  --board-b: #1b1f27;
  --highlight: rgba(255, 214, 10, 0.22);
}

/* ---------- base ---------- */

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

/* The page's content sits in <main>, laid out exactly as <body> lays out
   its own children: one centred column. */
main {
  display: flex;
  flex-direction: column;
  align-items: center;
  align-self: stretch;
  min-width: 0;
}
main:focus { outline: none; }

/* Hidden until a keyboard user tabs to it; then the first thing on the page. */
.skip-link {
  position: absolute;
  left: 8px;
  top: -100px;
  z-index: 600;
  padding: 10px 16px;
  border-radius: 10px;
  background: var(--accent);
  color: var(--accent-text);
  font-weight: 650;
  text-decoration: none;
}
.skip-link:focus { top: 8px; color: var(--accent-text); }

body {
  margin: 0;
  /* max(): on a phone with a notch or rounded corners, stay clear of them
     (the viewport is viewport-fit=cover, for when this runs inside an app). */
  padding: 0 max(16px, env(safe-area-inset-right)) max(48px, env(safe-area-inset-bottom)) max(16px, env(safe-area-inset-left));
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  display: flex;
  flex-direction: column;
  align-items: center;
}

a { color: var(--accent); text-decoration-thickness: 1px; text-underline-offset: 2px; }
a:hover { color: var(--accent-hover); }

:focus-visible { outline: 3px solid var(--focus); outline-offset: 2px; }

h1 {
  /* a rem part as well as vw, so it grows when the player asks for bigger text */
  font-size: clamp(1.6rem, 1.1rem + 2vw, 2.1rem);
  line-height: 1.15;
  letter-spacing: -0.02em;
  font-weight: 750;
  margin: 8px 0 10px;
  text-align: center;
}

p.byline { margin: 10px 0 24px; color: var(--muted); font-size: 0.9rem; text-align: center; }

code {
  font-family: var(--mono);
  font-size: 0.88em;
  background: var(--surface-2);
  padding: 1px 5px;
  border-radius: 5px;
}

/* ---------- header / footer ---------- */

.site-header {
  align-self: stretch;
  margin: 0 -16px 24px;
  padding: 10px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  border-bottom: 1px solid var(--border);
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: saturate(1.4) blur(10px);
  -webkit-backdrop-filter: saturate(1.4) blur(10px);
  position: sticky;
  top: 0;
  z-index: 500;
}
.site-header .brand { display: flex; align-items: center; line-height: 0; }
.site-header .brand img { height: 42px; width: auto; }
.site-header nav { display: flex; align-items: center; gap: 6px; }
.site-header nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 550;
  padding: 7px 12px;
  border-radius: 999px;
}
.site-header nav a:hover { color: var(--text); background: var(--surface-2); }
body.home .site-header .brand { visibility: hidden; }

.theme-toggle {
  width: 38px;
  height: 38px;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--text);
  cursor: pointer;
}
.theme-toggle:hover { background: var(--surface-2); }
.theme-toggle svg { width: 18px; height: 18px; }
.theme-toggle .moon { display: none; }

/* Show the logo (and icon) that matches the active theme. */
.logo-dark { display: none; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .logo-light { display: none; }
  :root:not([data-theme="light"]) .logo-dark { display: inline; }
  :root:not([data-theme="light"]) .theme-toggle .sun { display: none; }
  :root:not([data-theme="light"]) .theme-toggle .moon { display: inline; }
}
:root[data-theme="dark"] .logo-light { display: none; }
:root[data-theme="dark"] .logo-dark { display: inline; }
:root[data-theme="dark"] .theme-toggle .sun { display: none; }
:root[data-theme="dark"] .theme-toggle .moon { display: inline; }

.site-footer {
  align-self: stretch;
  margin: 56px -16px -48px;
  padding: 24px 20px 32px;
  border-top: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.82rem;
  text-align: center;
  line-height: 1.6;
}
.site-footer a { color: inherit; }

/* ---------- tags ---------- */

.tags { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; }
.tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.76rem;
  font-weight: 600;
  letter-spacing: 0.01em;
  padding: 3px 10px;
  border-radius: 999px;
  background: var(--accent-soft);
  color: var(--accent);
  text-decoration: none;
  white-space: nowrap;
  border: 1px solid transparent;
}
a.tag:hover { border-color: var(--accent); color: var(--accent); }
.tag .count { color: var(--muted); font-weight: 500; }

/* ---------- game page building blocks ---------- */

.stage {
  background: var(--stage);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
}

button {
  font: inherit;
  font-size: 0.9rem;
  font-weight: 550;
  padding: 8px 16px;
  border-radius: 10px;
  border: 1px solid var(--border-strong);
  background: var(--card);
  color: var(--text);
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
}
button:hover:not(:disabled) { background: var(--surface-2); }
button:disabled { opacity: 0.45; cursor: not-allowed; }
button[hidden] { display: none; }
button.primary {
  background: var(--accent);
  border-color: var(--accent);
  color: var(--accent-text);
}
button.primary:hover:not(:disabled) { background: var(--accent-hover); border-color: var(--accent-hover); }

input[type="number"], input[type="text"], select {
  font: inherit;
  font-size: 0.92rem;
  padding: 5px 8px;
  border-radius: 8px;
  border: 1px solid var(--border-strong);
  background: var(--card);
  color: var(--text);
}
input[type="radio"], input[type="checkbox"] { accent-color: var(--accent); }
select { max-width: 100%; min-width: 0; }

.controls {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  align-items: center;
  justify-content: center;
  margin-top: 18px;
  font-size: 0.9rem;
}
.controls label { display: flex; align-items: center; gap: 6px; white-space: nowrap; }
.controls input[type="number"] { width: 4em; }

fieldset {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 8px 12px 10px;
  background: var(--card);
}
legend { font-size: 0.75rem; font-weight: 600; text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted); padding: 0 6px; }

kbd {
  font-family: var(--mono);
  font-size: 0.85em;
  border: 1px solid var(--border-strong);
  border-bottom-width: 2px;
  border-radius: 5px;
  padding: 0 5px;
  background: var(--card);
}

#status { margin-top: 14px; min-height: 1.5em; font-size: 1rem; text-align: center; max-width: 560px; }
.win, #status.win { color: var(--good); font-weight: 650; }
.lose, #status.lose { color: var(--bad); font-weight: 650; }
/* finished, with nobody winning or losing */
#status.done { color: var(--accent); font-weight: 650; }

#rules {
  max-width: 600px;
  width: 100%;
  margin: 0 0 20px;
  padding: 14px 18px;
  font-size: 0.9rem;
  color: var(--muted);
  line-height: 1.55;
  text-align: center;
  background: var(--surface);
  border-radius: 12px;
}
#rules strong { color: var(--text); }

/* "Look for the math" */
details#math {
  max-width: 640px;
  width: 100%;
  margin-top: 20px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--card);
}
details#math summary {
  cursor: pointer;
  list-style: none;
  padding: 14px 18px;
  font-weight: 650;
  font-size: 1rem;
  color: var(--text);
  display: flex;
  align-items: center;
  gap: 10px;
}
details#math summary::-webkit-details-marker { display: none; }
details#math summary::before {
  content: "";
  width: 8px;
  height: 8px;
  border-right: 2px solid var(--accent);
  border-bottom: 2px solid var(--accent);
  transform: rotate(-45deg);
  transition: transform 0.2s;
}
details#math[open] summary::before { transform: rotate(45deg); }
details#math summary:hover { color: var(--accent); }
details#math .math-body {
  padding: 0 22px 18px;
  font-size: 0.95rem;
  line-height: 1.65;
  color: var(--text);
}
details#math .math-body h2 { font-size: 1rem; margin: 22px 0 4px; letter-spacing: -0.01em; }
details#math .math-body blockquote {
  margin: 10px 0;
  padding: 6px 14px;
  border-left: 3px solid var(--accent);
  background: var(--surface);
  border-radius: 0 8px 8px 0;
  color: var(--muted);
}

/* Wikipedia-style hover cards */
.wiki-term {
  text-decoration: underline dotted;
  text-decoration-color: var(--muted);
  text-underline-offset: 3px;
  color: inherit;
  cursor: help;
}
.wiki-card {
  position: absolute;
  z-index: 1000;
  width: 300px;
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 12px;
  box-shadow: var(--shadow-hover);
  padding: 12px;
  font-size: 0.82rem;
  line-height: 1.45;
  color: var(--text);
  display: none;
}
.wiki-card.visible { display: block; }
.wiki-card img {
  float: right;
  width: 72px;
  height: 72px;
  object-fit: cover;
  border-radius: 8px;
  margin-left: 10px;
}
.wiki-card h4 { margin: 0 0 4px; font-size: 0.92rem; }
.wiki-card p { margin: 0; }
.wiki-card a.wiki-more { display: inline-block; margin-top: 8px; font-size: 0.78rem; }
.wiki-card .wiki-loading { color: var(--muted); }

/* For a player who has asked for less motion: every transition and
   animation, here and in any page's own styles, finishes at once. They are
   cut short rather than removed, so code waiting for one to end still hears. */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    transition-duration: 0.01ms !important;
    transition-delay: 0s !important;
    animation-duration: 0.01ms !important;
    animation-delay: 0s !important;
    animation-iteration-count: 1 !important;
    scroll-behavior: auto !important;
  }
}

details#math .tip { font-size: 0.85rem; color: var(--muted); margin-top: 18px; }

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  white-space: nowrap;
}