/* ============================================================
   Maze Pathfinder — stylesheet
   Palette: dark neutral background, light walls, teal/violet
   search waves, amber shortest path, green/red endpoints.
   ============================================================ */

:root {
  color-scheme: dark;

  /* Surfaces & text */
  --bg: #0e1117;
  --panel: #161b24;
  --panel-border: #262e3d;
  --text: #e8ebf4;
  --text-muted: #8b93a7;

  /* Board */
  --cell: 24px;            /* overwritten by script.js on resize */
  --cell-empty: #1b212d;
  --cell-gap: #10141c;
  --wall: #ccd3e2;

  /* Actors */
  --start: #2fd377;        /* A — green  */
  --end: #ff5d5d;          /* B — red    */

  /* Search waves */
  --wave-a: #1d5f70;       /* settled tint, A side (teal)   */
  --wave-a-bright: #3fd2e8;
  --wave-b: #533070;       /* settled tint, B side (violet) */
  --wave-b-bright: #c084fc;

  /* Result */
  --path: #ffc53d;         /* amber */
  --meet: #ffffff;

  --accent: #4f8cff;
  --radius: 12px;
  --shadow: 0 14px 40px rgba(0, 0, 0, 0.45);
}

* {
  box-sizing: border-box;
}

/* The hidden attribute must always win, even over display: flex rules */
[hidden] {
  display: none !important;
}

html,
body {
  margin: 0;
}

body {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  background: var(--bg);
  color: var(--text);
  font-family:
    Inter,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    Roboto,
    "Helvetica Neue",
    Arial,
    sans-serif;
  -webkit-font-smoothing: antialiased;
}

/* ---------- Header ---------- */

.site-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  padding: 1.1rem 1.5rem 0.4rem;
  max-width: 1060px;
  width: 100%;
  margin: 0 auto;
}

.site-header h1 {
  margin: 0;
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.tagline {
  margin: 0.2rem 0 0;
  color: var(--text-muted);
  font-size: 0.86rem;
  max-width: 46rem;
}

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

.app {
  flex: 1;
  width: 100%;
  max-width: 1060px;
  margin: 0 auto;
  padding: 0.6rem 1.5rem 0.75rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.6rem;
}

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

.btn {
  appearance: none;
  border: 1px solid var(--panel-border);
  background: #1d2430;
  color: var(--text);
  font: inherit;
  font-size: 0.84rem;
  font-weight: 600;
  padding: 0.42rem 0.75rem;
  border-radius: 9px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.42rem;
  transition:
    background 120ms ease,
    border-color 120ms ease,
    transform 80ms ease,
    opacity 120ms ease;
}

.btn:hover:not(:disabled) {
  background: #242c3b;
  border-color: #35405a;
}

.btn:active:not(:disabled) {
  transform: translateY(1px);
}

.btn:disabled {
  opacity: 0.42;
  cursor: not-allowed;
}

.btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: #fff;
}

.btn-primary:hover:not(:disabled) {
  background: #3f7df4;
  border-color: #3f7df4;
}

.btn-ghost {
  background: transparent;
  color: var(--text-muted);
  font-weight: 500;
  text-decoration: none;
}

.btn-ghost:hover {
  background: #1d2430;
  color: var(--text);
}

/* Pressed state for mode / speed toggles */
.mode-btn[aria-pressed="true"],
.speed-btn[aria-pressed="true"] {
  background: #2a3550;
  border-color: var(--accent);
  box-shadow: inset 0 0 0 1px var(--accent);
}

/* ---------- Toolbar ---------- */

.toolbar {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 0.55rem 1.1rem;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  padding: 0.6rem 0.85rem;
  box-shadow: var(--shadow);
}

.tool-group {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  flex-wrap: wrap;
}

.tool-group + .tool-group {
  padding-left: 1.1rem;
  border-left: 1px solid var(--panel-border);
}

.speed-label,
.group-label {
  color: var(--text-muted);
  font-size: 0.78rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}

/* Algorithm dropdown, styled to match the buttons */
.algo-select {
  appearance: none;
  -webkit-appearance: none;
  font: inherit;
  font-size: 0.84rem;
  font-weight: 600;
  color: var(--text);
  background:
    url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='6'%3E%3Cpath d='M1 1l4 4 4-4' stroke='%238b93a7' stroke-width='1.6' fill='none' stroke-linecap='round'/%3E%3C/svg%3E")
      no-repeat right 0.6rem center,
    #1d2430;
  border: 1px solid var(--panel-border);
  border-radius: 9px;
  padding: 0.42rem 1.7rem 0.42rem 0.75rem;
  cursor: pointer;
  transition:
    background-color 120ms ease,
    border-color 120ms ease;
}

.algo-select:hover:not(:disabled) {
  border-color: #35405a;
}

.algo-select:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.algo-select:disabled {
  opacity: 0.42;
  cursor: not-allowed;
}

.algo-select option:disabled {
  color: #5b6273;
}

.speed-btn {
  font-weight: 500;
  padding: 0.34rem 0.6rem;
}

/* ---------- Status line ---------- */

.status {
  margin: 0;
  min-height: 1.3em;
  font-size: 0.88rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

.status strong {
  color: var(--text);
}

.status.is-success {
  color: var(--path);
}

.status.is-error {
  color: var(--end);
}

/* ---------- Board ---------- */

.board-wrap {
  position: relative;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: var(--radius);
  padding: 10px;
  box-shadow: var(--shadow);
  max-width: 100%;
}

.board {
  display: grid;
  gap: 1px;
  background: var(--cell-gap);
  touch-action: none; /* let pointer events handle drag-painting on touch */
  user-select: none;
  border-radius: 6px;
  overflow: hidden;
}

.board.is-locked {
  cursor: progress;
}

.cell {
  width: var(--cell);
  height: var(--cell);
  background: var(--cell-empty);
}

.board:not(.is-locked) .cell:hover {
  filter: brightness(1.35);
}

.cell.wall {
  background: var(--wall);
  box-shadow: inset 0 -2px 0 rgba(0, 0, 0, 0.22);
}

/* Search waves: bloom in bright, settle into the tint */
.cell.visited-a {
  background: var(--wave-a);
  animation: bloom-a 450ms ease-out;
}

.cell.visited-b {
  background: var(--wave-b);
  animation: bloom-b 450ms ease-out;
}

@keyframes bloom-a {
  from {
    background: var(--wave-a-bright);
    transform: scale(0.35);
    border-radius: 50%;
  }
  to {
    background: var(--wave-a);
    transform: scale(1);
    border-radius: 0;
  }
}

@keyframes bloom-b {
  from {
    background: var(--wave-b-bright);
    transform: scale(0.35);
    border-radius: 50%;
  }
  to {
    background: var(--wave-b);
    transform: scale(1);
    border-radius: 0;
  }
}

/* Final shortest path */
.cell.path {
  background: var(--path);
  animation: pop-path 320ms ease-out;
}

@keyframes pop-path {
  from {
    transform: scale(0.3);
    border-radius: 50%;
  }
  60% {
    transform: scale(1.15);
  }
  to {
    transform: scale(1);
    border-radius: 0;
  }
}

/* Meeting point of the two waves */
.cell.meet {
  box-shadow: inset 0 0 0 2px var(--meet);
}

/* Endpoints — drawn as rounded chips with a letter */
.cell.start,
.cell.end {
  position: relative;
  z-index: 1;
}

.cell.start::after,
.cell.end::after {
  content: "A";
  position: absolute;
  inset: 8%;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: 28%;
  font-size: calc(var(--cell) * 0.52);
  font-weight: 800;
  color: #08140c;
  background: var(--start);
  box-shadow: 0 0 0 2px rgba(0, 0, 0, 0.35);
}

.cell.end::after {
  content: "B";
  color: #1c0808;
  background: var(--end);
}

/* ---------- "This is the path" callout ---------- */

.callout {
  position: absolute;
  z-index: 5;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 0.38rem 0.65rem;
  background: #f4f6fb;
  color: #12151c;
  border-radius: 9px;
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.5);
  transform: translate(-50%, calc(-100% - 12px));
  pointer-events: none;
  animation: callout-in 260ms ease-out;
  white-space: nowrap;
}

.callout::after {
  content: "";
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 7px solid transparent;
  border-top-color: #f4f6fb;
}

/* Flipped below the cell when the meeting point is near the top edge */
.callout.below {
  transform: translate(-50%, 12px);
}

.callout.below::after {
  top: auto;
  bottom: 100%;
  border-top-color: transparent;
  border-bottom-color: #f4f6fb;
}

.callout-title {
  font-size: 0.82rem;
  font-weight: 700;
}

.callout-sub {
  font-size: 0.72rem;
  color: #565e70;
}

@keyframes callout-in {
  from {
    opacity: 0;
    margin-top: -6px;
  }
  to {
    opacity: 1;
    margin-top: 0;
  }
}

/* ---------- Legend ---------- */

.legend {
  list-style: none;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.35rem 1.05rem;
  margin: 0;
  padding: 0;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.legend li {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
}

/* Small color chips used in the legend and mode buttons */
.swatch {
  width: 12px;
  height: 12px;
  border-radius: 4px;
  display: inline-block;
  flex: none;
}

.swatch-wall {
  background: var(--wall);
}

.swatch-erase {
  background: var(--cell-empty);
  box-shadow: inset 0 0 0 1px #3a4356;
}

.swatch-start {
  background: var(--start);
}

.swatch-end {
  background: var(--end);
}

.swatch-wave-a {
  background: linear-gradient(135deg, var(--wave-a-bright), var(--wave-a));
}

.swatch-wave-b {
  background: linear-gradient(135deg, var(--wave-b-bright), var(--wave-b));
}

.swatch-path {
  background: var(--path);
}

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

.site-footer {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.7rem;
  padding: 0.55rem 1rem 1rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  letter-spacing: 0.03em;
}

.footer-text {
  font-weight: 600;
}

.footer-links {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
}

.footer-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border-radius: 8px;
  color: var(--text-muted);
  transition:
    color 120ms ease,
    background 120ms ease;
}

.footer-icon:hover {
  color: var(--text);
  background: #1d2430;
}

.footer-icon:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ---------- Small screens ---------- */

@media (max-width: 640px) {
  .site-header {
    padding: 0.9rem 1rem 0.3rem;
  }

  .app {
    padding: 0.5rem 0.6rem 0.6rem;
  }

  .tool-group + .tool-group {
    padding-left: 0;
    border-left: 0;
  }

  .board-wrap {
    padding: 6px;
  }
}

/* Respect users who prefer no motion: skip the bloom/pop animations */
@media (prefers-reduced-motion: reduce) {
  .cell.visited-a,
  .cell.visited-b,
  .cell.path,
  .callout {
    animation: none;
  }
}