/*
  Shared synthwave theme for the parityBits, sortingVisualiser and lamps tools
  (and the landing page). Tool-specific rules live in each tool's own stylesheet.
  pickUpSticks and binaryEscape deliberately do not use this file.
  A lighter "chill" variant is at the bottom, toggled by theme.js via <html data-theme="chill">.

  Link it with:  <link rel="stylesheet" href="../synthwave.css">
                 <script src="../theme.js"></script>   (in <head>)
*/

/* ---------- Design tokens ---------- */
:root {
  --bg: #0d0221;
  --bg-mid: #261447;
  --bg-glow: #4a1a6b;
  --pink: #ff2a6d;
  --cyan: #05d9e8;
  --purple: #7b2ff7;
  --yellow: #f9c80e;
  --green: #39ff14;
  --text: #e8d9ff;
  --muted: #9b7fd1;
  --surface: rgba(13, 2, 33, .8);
  --surface-solid: #1a0b3a;
  --canvas-bg: #07010f;
  --hi: #fff;              /* brightest text: headings, hovered links, key readouts */
  --lit: #f9c80e;          /* fill for "on" lamps and switches */
  --line: rgba(255, 255, 255, .15);
  --line-strong: rgba(255, 255, 255, .35);
  --font: "Share Tech Mono", "Consolas", "Courier New", monospace;
}

/* ---------- Base ---------- */
* { box-sizing: border-box; }
body {
  margin: 0;
  min-height: 100vh;
  overflow-x: hidden;
  color: var(--text);
  font-family: var(--font);
  line-height: 1.5;
  background: linear-gradient(var(--bg) 0%, var(--bg-mid) 60%, var(--bg-glow) 100%) fixed;
}

/* Backdrop: striped sun and a scrolling perspective floor, drawn behind all content */
body::before {
  content: "";
  position: fixed; left: 50%; bottom: 8vh; z-index: -1;
  width: 50vmin; height: 50vmin; transform: translateX(-50%);
  border-radius: 50%; opacity: .35; pointer-events: none;
  background: linear-gradient(var(--yellow), var(--pink) 60%, var(--purple));
  -webkit-mask: repeating-linear-gradient(#000 0 14px, transparent 14px 20px);
  mask: repeating-linear-gradient(#000 0 14px, transparent 14px 20px);
}
body::after {
  content: "";
  position: fixed; left: -50%; right: -50%; bottom: 0; z-index: -1;
  height: 40vh; opacity: .35; pointer-events: none;
  background-image:
    linear-gradient(var(--purple) 1px, transparent 1px),
    linear-gradient(90deg, var(--purple) 1px, transparent 1px);
  background-size: 60px 40px;
  transform: perspective(300px) rotateX(60deg); transform-origin: bottom;
  animation: floor-scroll 2s linear infinite;
}
@keyframes floor-scroll { to { background-position: 0 40px; } }

/* ---------- Layout ---------- */
.page { max-width: 1300px; margin: 0 auto; padding: 24px 16px 60px; }
.page--narrow { max-width: 1024px; }

.site-nav { display: flex; flex-wrap: wrap; gap: 8px 20px; justify-content: space-between; margin-bottom: 12px; text-align: left; }
.site-nav a { color: var(--cyan); text-decoration: none; text-transform: uppercase; letter-spacing: .1em; font-size: .85rem; }
.site-nav a:hover, .site-nav a:focus-visible { color: var(--hi); text-shadow: 0 0 8px var(--cyan); }
.site-nav a[aria-current="page"] { color: var(--pink); pointer-events: none; }

.site-header { text-align: center; margin-bottom: 20px; }
h1 {
  margin: 0 0 4px; font-size: clamp(1.8rem, 6vw, 3.4rem); font-style: italic;
  letter-spacing: .15em;   text-transform: uppercase; color: var(--hi);
  text-shadow: 0 0 6px var(--pink), 0 0 18px var(--pink), 0 0 40px var(--pink);
}
h1 .alt { color: var(--cyan); text-shadow: 0 0 6px var(--cyan), 0 0 18px var(--cyan), 0 0 40px var(--cyan); }
h2 { margin: 0 0 8px; font-size: 1.1rem; color: var(--yellow); text-shadow: 0 0 8px var(--yellow); }

.tagline { margin: 0 0 20px; letter-spacing: .08em; color: var(--cyan); text-shadow: 0 0 8px var(--cyan); }
.tagline::before { content: "> "; color: var(--pink); }
.tagline::after { content: "_"; animation: blink 1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }

/* ---------- Panels ---------- */
.panel {
  background: var(--surface); border: 1px solid var(--pink); border-radius: 12px; padding: 16px;
  box-shadow: 0 0 18px rgba(255, 42, 109, .4);
}
.panel--cyan { border-color: var(--cyan); box-shadow: 0 0 18px rgba(5, 217, 232, .35); }
.panel--purple { border-color: var(--purple); box-shadow: 0 0 20px rgba(123, 47, 247, .5); }

fieldset { border: 1px solid var(--pink); border-radius: 8px; margin: 0; padding: 8px 12px; }
legend { color: var(--pink); padding: 0 6px; text-transform: uppercase; letter-spacing: .1em; font-size: .8rem; }

.controls { display: flex; flex-wrap: wrap; gap: 12px; justify-content: center; align-items: center; }
.row { display: flex; flex-wrap: wrap; gap: 20px; align-items: center; }
label { letter-spacing: .06em; }

/* ---------- Buttons ---------- */
.btn {
  font: inherit; font-weight: 600; text-transform: uppercase; letter-spacing: .08em;
  padding: 8px 16px; cursor: pointer; text-decoration: none; display: inline-block;
  background: var(--surface); color: var(--cyan); border: 2px solid var(--cyan); border-radius: 6px;
  box-shadow: 0 0 8px rgba(5, 217, 232, .6), inset 0 0 8px rgba(5, 217, 232, .25);
  text-shadow: 0 0 6px var(--cyan);
  transition: background .15s, color .15s, box-shadow .15s, transform .05s;
}
.btn:hover:not(:disabled) { background: var(--cyan); color: var(--bg); text-shadow: none; box-shadow: 0 0 18px var(--cyan); }
.btn:active:not(:disabled) { transform: translateY(1px); }
.btn--primary { color: var(--pink); border-color: var(--pink); text-shadow: 0 0 6px var(--pink); box-shadow: 0 0 8px rgba(255, 42, 109, .6), inset 0 0 8px rgba(255, 42, 109, .25); }
.btn--primary:hover:not(:disabled) { background: var(--pink); color: #fff; box-shadow: 0 0 18px var(--pink); }
.btn:disabled { opacity: .35; cursor: default; }
[hidden] { display: none !important; }

/* Two or more buttons that act as a mode switch; the active one is marked with aria-pressed */
.segmented { display: inline-flex; border: 2px solid var(--cyan); border-radius: 6px; overflow: hidden; box-shadow: 0 0 8px rgba(5, 217, 232, .6); }
.segmented button {
  font: inherit; font-weight: 600; text-transform: uppercase; letter-spacing: .06em; cursor: pointer;
  padding: 8px 16px; background: transparent; color: var(--muted); border: 0;
  transition: background .15s, color .15s;
}
.segmented button + button { border-left: 2px solid var(--cyan); }
.segmented button:hover { color: var(--hi); }
.segmented button[aria-pressed="true"] { background: var(--cyan); color: var(--bg); }

/* ---------- Form controls ---------- */
select, input[type="text"], input[type="number"] {
  font: inherit; color: var(--text); background: var(--surface-solid);
  border: 1px solid var(--cyan); border-radius: 6px; padding: 8px 10px;
}
input[type="text"], input[type="number"] { font-variant-numeric: tabular-nums; }
select { cursor: pointer; }
select:hover { box-shadow: 0 0 10px var(--cyan); }
select option { background: var(--bg); color: var(--cyan); }
input::placeholder { color: var(--muted); opacity: .7; }
input[type="range"], input[type="checkbox"], input[type="radio"] { accent-color: var(--pink); }
output { min-width: 2.5ch; color: var(--yellow); }

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

/* ---------- Display boxes (big readouts / targets) ---------- */
.display-box {
  display: flex; flex-direction: column; align-items: center; gap: 6px; padding: 12px 20px; text-align: center;
  background: var(--canvas-bg); border: 2px solid var(--cyan); border-radius: 10px;
  box-shadow: 0 0 14px rgba(5, 217, 232, .35), inset 0 0 14px rgba(5, 217, 232, .12);
}
.display-label { color: var(--muted); font-size: .9rem; text-transform: uppercase; letter-spacing: .1em; }
.display-value {
  font-size: clamp(2rem, 6vw, 3.2rem); font-weight: 700; color: var(--hi); letter-spacing: .08em;
  text-shadow: 0 0 10px var(--cyan); font-variant-numeric: tabular-nums;
}
.display-value.is-concealed { color: var(--muted); text-shadow: none; }
.display-value.is-over { color: var(--pink); text-shadow: 0 0 10px var(--pink); }
.display-value.is-done { color: var(--green); text-shadow: 0 0 10px var(--green); }

.chip { display: inline-block; padding: 2px 12px; border: 1px solid var(--cyan); border-radius: 999px; color: var(--cyan); }
.hint { color: var(--muted); font-size: .95rem; }

/* ---------- Feedback colours ---------- */
.text-good { color: var(--green); text-shadow: 0 0 6px var(--green); }
.text-bad { color: var(--pink); text-shadow: 0 0 6px var(--pink); }
.text-warn { color: var(--yellow); text-shadow: 0 0 6px var(--yellow); }
.feedback { font-weight: 700; min-height: 1.6em; }

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

/* Theme switch, injected by theme.js */
.theme-toggle { margin-left: auto; padding: 4px 12px; font-size: .8rem; }
.theme-toggle[aria-pressed="true"] { background: var(--cyan); color: var(--bg); text-shadow: none; }

/* ---------- Chill theme: soft pastel "chillsynth / dreamwave" variant ----------
   Switched on with <html data-theme="chill"> (see theme.js). Same layout, lighter colours. */
:root[data-theme="chill"] {
  --bg: #fff3fb;
  --bg-mid: #eadcfb;
  --bg-glow: #cfe6ff;
  --pink: #cc3f78;
  --cyan: #0c8599;
  --purple: #8a5cf0;
  --yellow: #b86e00;
  --green: #11805a;
  --text: #3b2a5c;
  --muted: #6f5f96;
  --surface: rgba(255, 255, 255, .65);
  --surface-solid: #fff8fd;
  --canvas-bg: #fffafe;
  --hi: #2a1650;
  --lit: #ffcf5c;
  --line: rgba(138, 92, 240, .25);
  --line-strong: rgba(138, 92, 240, .5);
}
/* Neon glows turn into soft pastel halos */
:root[data-theme="chill"] body *, :root[data-theme="chill"] body *::after { text-shadow: none !important; }
:root[data-theme="chill"] h1 { color: var(--pink); text-shadow: 3px 3px 0 color-mix(in srgb, var(--cyan) 30%, transparent) !important; }
:root[data-theme="chill"] h1 .alt { color: var(--cyan); text-shadow: 3px 3px 0 color-mix(in srgb, var(--pink) 30%, transparent) !important; }
:root[data-theme="chill"] body::before {
  opacity: .6;
  background: linear-gradient(#ffd89b, #ff9ec7 60%, #b79cff);
}
:root[data-theme="chill"] body::after { opacity: .3; }
:root[data-theme="chill"] .panel { box-shadow: 0 6px 24px rgba(204, 63, 120, .18); }
:root[data-theme="chill"] .panel--cyan { box-shadow: 0 6px 24px rgba(12, 133, 153, .18); }
:root[data-theme="chill"] .panel--purple { box-shadow: 0 6px 24px rgba(138, 92, 240, .22); }
:root[data-theme="chill"] .btn,
:root[data-theme="chill"] .segmented { box-shadow: 0 2px 10px rgba(12, 133, 153, .2); }
:root[data-theme="chill"] .btn--primary { box-shadow: 0 2px 10px rgba(204, 63, 120, .22); }
:root[data-theme="chill"] .btn:hover:not(:disabled) { box-shadow: 0 4px 16px rgba(12, 133, 153, .35); }
:root[data-theme="chill"] .btn--primary:hover:not(:disabled) { box-shadow: 0 4px 16px rgba(204, 63, 120, .4); }
:root[data-theme="chill"] .display-box { box-shadow: 0 4px 16px rgba(12, 133, 153, .18); }

@media (prefers-reduced-motion: reduce) {
  body::after, .tagline::after { animation: none; }
}