/* ── Reset ───────────────────────────────────────────────────── */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

/* ── Design Tokens ───────────────────────────────────────────── */
:root {
  --clr-bg:        #63C2FF;
  --clr-primary:   #4CAF50;
  --clr-secondary: #2196F3;
  --clr-pink:      #FF4081;
  --clr-accent:    #FFD700;
  --clr-green:     #4caf50;
  --clr-text:      #ffffff;
  --clr-text-dim:  rgba(255, 255, 255, 0.75);
  --clr-overlay:   rgba(15, 65, 155, 0.82);
  --clr-border:    rgba(255, 255, 255, 0.25);

  --radius-btn:  12px;
  --radius-card: 18px;

  --btn-h:        56px;
  --btn-w-min:    220px;
  --icon-btn-sz:  56px;

  /* Safe area (iPhone notch / Android navigation bar) */
  --safe-t: env(safe-area-inset-top,    0px);
  --safe-r: env(safe-area-inset-right,  0px);
  --safe-b: env(safe-area-inset-bottom, 0px);
  --safe-l: env(safe-area-inset-left,   0px);
}

/* ── Base ────────────────────────────────────────────────────── */
html, body {
  width: 100%;
  height: 100%;
  overflow: hidden;
  background: var(--clr-bg);
  font-family: system-ui, -apple-system, 'Segoe UI', sans-serif;
  color: var(--clr-text);
  -webkit-tap-highlight-color: transparent;
  -webkit-font-smoothing: antialiased;
}

/* ── App root ────────────────────────────────────────────────── */
#app {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  /* Sky gradient visible in the strips around the canvas */
  background: linear-gradient(
    to bottom,
    #1E70B0 0%,
    #3298D8 10%,
    #4AAEE8 20%,
    #63C2FF 38%,
    #88D4FF 60%,
    #A8E8FF 78%,
    #C0F4FF 100%
  );
}

/* Ground/earth strip fills the space below the canvas.
   height = (viewport_h - canvas_h) / 2, where canvas_h = min(100vh, 56.25vw) */
#app::after {
  content: '';
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: calc((100vh - min(100vh, 56.25vw)) / 2);
  background: linear-gradient(
    to bottom,
    #7ECC6E 0%,
    #5CB85C 12%,
    #4CAF50 24%,
    #3A8840 48%,
    #276427 72%,
    #1A4A1A 100%
  );
  pointer-events: none;
  z-index: 0;
}

/* ── Canvas ──────────────────────────────────────────────────── */
#game-canvas {
  position: relative;
  z-index: 1;
  display: block;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
  image-rendering: pixelated;
  image-rendering: crisp-edges;
}

/* ── Screens (overlay system) ────────────────────────────────── */
.screen {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 10;
}

.screen--hidden {
  display: none;
}

.screen--active {
  display: flex;
}

/* Transparent overlay: used for HUD */
.screen--overlay {
  background: transparent;
  pointer-events: none;
}

.screen--overlay > * {
  pointer-events: auto;
}

/* ── Screen Inner (card) ─────────────────────────────────────── */
.screen__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 14px;
  padding: 32px 28px;
  padding-top:    calc(32px + var(--safe-t));
  padding-bottom: calc(32px + var(--safe-b));
  background: var(--clr-overlay);
  border-radius: var(--radius-card);
  border: 1px solid var(--clr-border);
  min-width: 280px;
  max-width: 380px;
  width: 90vw;
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.screen__inner--loading {
  background: transparent;
  border: none;
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
}

.screen__inner--shop {
  max-height: 90svh;
  overflow-y: auto;
  overscroll-behavior: contain;
}

/* ── Loading Screen ──────────────────────────────────────────── */
#loading-screen {
  background: var(--clr-bg);
  z-index: 100;
}

/* ── Logo ────────────────────────────────────────────────────── */
.logo__sub {
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 8px;
  color: var(--clr-accent);
  text-transform: uppercase;
}

.logo__title {
  font-size: 56px;
  font-weight: 900;
  letter-spacing: 6px;
  line-height: 1;
  color: var(--clr-text);
  text-shadow: 0 0 24px rgba(255, 64, 129, 0.65);
}

/* ── Progress Bar ────────────────────────────────────────────── */
.progress-bar {
  width: 240px;
  height: 6px;
  background: rgba(255, 255, 255, 0.12);
  border-radius: 3px;
  overflow: hidden;
}

.progress-bar__fill {
  height: 100%;
  width: 0%;
  background: var(--clr-primary);
  border-radius: 3px;
  transition: width 0.25s ease;
  will-change: width;
}

.progress-text {
  font-size: 13px;
  letter-spacing: 1px;
  color: var(--clr-text-dim);
}

/* ── Screen Title ────────────────────────────────────────────── */
.screen__title {
  font-size: 26px;
  font-weight: 800;
  letter-spacing: 3px;
  text-align: center;
}

/* ── Record Block ────────────────────────────────────────────── */
.record-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 2px;
}

.record-block__label {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 3px;
  color: var(--clr-text-dim);
  text-transform: uppercase;
}

.record-block__value {
  font-size: 34px;
  font-weight: 800;
  color: var(--clr-accent);
}

/* ── Buttons ─────────────────────────────────────────────────── */
.btn {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: var(--btn-h);
  min-width: var(--btn-w-min);
  width: 100%;
  padding: 0 20px;
  border: none;
  border-radius: var(--radius-btn);
  font-size: 15px;
  font-weight: 700;
  letter-spacing: 1.5px;
  text-transform: uppercase;
  cursor: pointer;
  touch-action: manipulation;
  transition: transform 0.12s ease, opacity 0.12s ease;
  -webkit-tap-highlight-color: transparent;
}

.btn:active {
  transform: scale(0.95);
  opacity: 0.88;
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn--primary   { background: var(--clr-primary);   color: var(--clr-text); }
.btn--secondary { background: var(--clr-secondary);  color: var(--clr-text); }
.btn--rewarded  { background: var(--clr-green);      color: var(--clr-text); font-size: 13px; }

.btn--icon {
  min-width:  var(--icon-btn-sz);
  width:      var(--icon-btn-sz);
  min-height: var(--icon-btn-sz);
  height:     var(--icon-btn-sz);
  padding: 0;
  border-radius: 50%;
  background: var(--clr-pink);
  font-size: 20px;
}

/* ── HUD ─────────────────────────────────────────────────────── */
.hud {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 10px 16px;
  padding-top:   calc(10px + var(--safe-t));
  padding-left:  calc(16px + var(--safe-l));
  padding-right: calc(16px + var(--safe-r));
  pointer-events: none;
}

.hud__btn {
  pointer-events: auto;
  width:  48px;
  height: 48px;
  border: none;
  border-radius: 50%;
  background: rgba(0, 0, 0, 0.38);
  color: var(--clr-text);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  touch-action: manipulation;
  -webkit-tap-highlight-color: transparent;
  transition: background 0.15s ease;
}

.hud__btn:active { background: rgba(0, 0, 0, 0.6); }

.hud__distance {
  font-size: 20px;
  font-weight: 700;
  text-shadow: 0 1px 6px rgba(0, 0, 0, 0.7);
}

.hud__coins {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 20px;
  font-weight: 700;
  color: var(--clr-accent);
  text-shadow: 0 1px 6px rgba(0, 0, 0, 0.7);
}

/* ── Stats Grid ──────────────────────────────────────────────── */
.stats-grid {
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.stats-grid__row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 10px 0;
  border-bottom: 1px solid var(--clr-border);
}

.stats-grid__label {
  font-size: 13px;
  color: var(--clr-text-dim);
  letter-spacing: 0.5px;
}

.stats-grid__value {
  font-size: 18px;
  font-weight: 700;
}

.stats-grid__row--accent .stats-grid__value {
  color: var(--clr-accent);
  font-size: 22px;
}

/* ── Shop ────────────────────────────────────────────────────── */
.shop-balance {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 26px;
  font-weight: 800;
  color: var(--clr-accent);
}

.shop-items {
  width: 100%;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

/* ── CSS Icons ───────────────────────────────────────────────── */

/* Pause: two vertical bars */
.icon-pause {
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

.icon-pause::before,
.icon-pause::after {
  content: '';
  display: block;
  width: 4px;
  height: 16px;
  background: currentColor;
  border-radius: 2px;
}

/* Sound note */
.icon-sound::before {
  content: '\266A';
  font-size: 20px;
  line-height: 1;
}

.icon-sound--off::before {
  content: '\2715';
  font-size: 18px;
  color: var(--clr-text-dim);
}

/* Coin dot */
.coin-icon {
  display: inline-block;
  width:  16px;
  height: 16px;
  background: var(--clr-accent);
  border-radius: 50%;
  border: 2px solid rgba(255, 255, 255, 0.35);
  flex-shrink: 0;
}

/* ── Scrollbar (Shop) ────────────────────────────────────────── */
.screen__inner--shop::-webkit-scrollbar        { width: 4px; }
.screen__inner--shop::-webkit-scrollbar-track  { background: transparent; }
.screen__inner--shop::-webkit-scrollbar-thumb  { background: rgba(255,255,255,0.2); border-radius: 2px; }

/* ── HUD Toast notification ──────────────────────────────────── */
.hud-toast {
  position: absolute;
  top: calc(56px + var(--safe-t));
  left: 50%;
  transform: translateX(-50%) translateY(-8px);
  background: rgba(245, 166, 35, 0.92);
  color: #1a1a2e;
  font-size: 14px;
  font-weight: 800;
  letter-spacing: 1px;
  padding: 6px 18px;
  border-radius: 20px;
  white-space: nowrap;
  pointer-events: none;
  transition: opacity 0.25s ease, transform 0.25s ease;
}

.hud-toast--hidden  { opacity: 0; transform: translateX(-50%) translateY(-12px); }
.hud-toast--visible { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ── FPS counter (debug overlay) ─────────────────────────────── */
.hud__fps {
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.5px;
  color: rgba(255, 255, 255, 0.4);
  min-width: 44px;
  text-align: right;
}

/* ── Fullscreen icon ─────────────────────────────────────────── */
.icon-fullscreen::before {
  content: '\26F6';   /* ⛶ expand symbol */
  font-size: 20px;
  line-height: 1;
}

.icon-fullscreen--exit::before {
  content: '\2715';   /* exit symbol */
  font-size: 18px;
  color: var(--clr-text-dim);
}

/* ── GPU compositing hints ───────────────────────────────────── */
/* Promote frequently animated elements to their own compositor layer */
#game-canvas,
.progress-bar__fill,
.hud-toast,
.screen {
  will-change: transform;
}