/* =============================================
   SNAKE GAME — STYLE SHEET
   Theme: retro terminal / neon green on black
   ============================================= */

/* ---------- CSS custom properties (design tokens) ---------- */
:root {
  --bg:          #080d08;          /* deep black-green background */
  --panel:       #0d1a0d;          /* slightly lighter panel */
  --neon:        #39ff14;          /* neon green — primary accent */
  --neon-dim:    #1a7a09;          /* dimmed green for borders / grid */
  --neon-glow:   rgba(57,255,20,.35); /* glow colour */
  --food:        #ff4c4c;          /* food dot red */
  --food-glow:   rgba(255,76,76,.5);
  --white:       #e8ffe8;
  --font:        'Press Start 2P', monospace;
  --cell:        20px;             /* grid cell size (overridden by JS) */
  --canvas-size: 400px;            /* canvas display size */
  --border:      2px solid var(--neon-dim);
  --radius:      4px;
}

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

body {
  background: var(--bg);
  color: var(--neon);
  font-family: var(--font);
  display: flex;
  justify-content: center;
  align-items: flex-start;
  min-height: 100vh;
  padding: 2rem 1rem;

  /* scanline effect via repeating gradient */
  background-image: repeating-linear-gradient(
    0deg,
    rgba(0,0,0,.15) 0px,
    rgba(0,0,0,.15) 1px,
    transparent 1px,
    transparent 3px
  );
}

/* ---------- Main layout wrapper ---------- */
.wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  width: 100%;
  max-width: 460px;
}

/* ---------- Title ---------- */
.title {
  font-size: clamp(1.5rem, 6vw, 2.5rem);
  letter-spacing: .35em;
  text-shadow:
    0 0 8px  var(--neon),
    0 0 24px var(--neon),
    0 0 60px var(--neon-glow);
  /* blinking cursor animation */
  animation: blink-shadow 2s step-end infinite;
}

@keyframes blink-shadow {
  0%, 100% { text-shadow: 0 0 8px var(--neon), 0 0 24px var(--neon), 0 0 60px var(--neon-glow); }
  50%       { text-shadow: none; }
}

/* ---------- HUD (score row) ---------- */
.hud {
  display: flex;
  gap: 1.5rem;
  align-items: baseline;
  font-size: .5rem;
  letter-spacing: .1em;
}

.hud-label {
  color: var(--neon-dim);
  font-size: .45rem;
}

.hud-value {
  font-size: .8rem;
  color: var(--white);
  text-shadow: 0 0 6px var(--neon);
  min-width: 4ch;
  text-align: right;
}

/* ---------- Canvas wrapper & overlay ---------- */
.canvas-wrapper {
  position: relative;
  width:  var(--canvas-size);
  height: var(--canvas-size);
  max-width: 100%;
  border: var(--border);
  box-shadow:
    0 0 12px var(--neon-dim),
    inset 0 0 30px rgba(0,0,0,.8);
  border-radius: var(--radius);
  overflow: hidden;
}

#gameCanvas {
  display: block;
  width:  100%;
  height: 100%;
  image-rendering: pixelated; /* keeps pixels crisp when scaled */
  background: var(--panel);
}

/* Overlay (start screen / game over) */
.overlay {
  position: absolute;
  inset: 0;
  background: rgba(8,13,8,.88);
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 1.2rem;
  backdrop-filter: blur(2px);
  transition: opacity .3s;
}

.overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.overlay-title {
  font-size: clamp(.7rem, 3.5vw, 1rem);
  letter-spacing: .15em;
  color: var(--neon);
  text-shadow: 0 0 12px var(--neon);
  text-align: center;
}

.overlay-sub {
  font-size: .4rem;
  color: var(--neon-dim);
  letter-spacing: .1em;
  text-align: center;
  line-height: 2;
}

/* START / RESTART button */
.btn-start {
  margin-top: .5rem;
  padding: .6rem 1.4rem;
  font-family: var(--font);
  font-size: .5rem;
  letter-spacing: .2em;
  color: var(--bg);
  background: var(--neon);
  border: none;
  border-radius: var(--radius);
  cursor: pointer;
  box-shadow: 0 0 18px var(--neon-glow);
  transition: transform .1s, box-shadow .1s;
}

.btn-start:hover  { transform: scale(1.05); box-shadow: 0 0 28px var(--neon); }
.btn-start:active { transform: scale(.97); }

/* ---------- Speed selector ---------- */
.speed-row {
  display: flex;
  align-items: center;
  gap: 1rem;
  font-size: .4rem;
}

.speed-btns { display: flex; gap: .4rem; }

.speed-btn {
  font-family: var(--font);
  font-size: .38rem;
  letter-spacing: .08em;
  color: var(--neon-dim);
  background: transparent;
  border: 1px solid var(--neon-dim);
  border-radius: var(--radius);
  padding: .3rem .6rem;
  cursor: pointer;
  transition: color .15s, border-color .15s, box-shadow .15s;
}

.speed-btn:hover,
.speed-btn.active {
  color: var(--neon);
  border-color: var(--neon);
  box-shadow: 0 0 8px var(--neon-glow);
}

/* ---------- Touch / mobile controls ---------- */
.touch-controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: .3rem;
  margin-top: .5rem;
}

.touch-row { display: flex; gap: .3rem; }

.touch-btn {
  width: 3.2rem;
  height: 3.2rem;
  font-size: 1rem;
  font-family: var(--font);
  color: var(--neon);
  background: var(--panel);
  border: var(--border);
  border-radius: var(--radius);
  cursor: pointer;
  box-shadow: 0 0 6px var(--neon-dim);
  transition: background .1s, box-shadow .1s;
  /* prevent text selection on rapid taps */
  user-select: none;
}

.touch-btn:active {
  background: var(--neon-dim);
  box-shadow: 0 0 14px var(--neon);
}

/* ---------- Responsive tweaks ---------- */
@media (max-width: 460px) {
  :root { --canvas-size: min(90vw, 360px); }
}