/* =================================================================
   Helix Drop - styles
   Mobile-first portrait, scales up.
   ================================================================= */
:root {
  --bg-0: #07081c;
  --bg-1: #1a1145;
  --bg-2: #3a1064;
  --fg: #f5f7ff;
  --fg-dim: #b6bbd9;
  --accent: #4ff0c5;
  --accent-2: #ff5cf2;
  --danger: #ff3b5e;
  --warn: #ffb547;
  --safe: #4ade80;
  --card: rgba(15, 18, 50, 0.85);
  --card-border: rgba(255, 255, 255, 0.08);
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.55);
  --tap-min: 48px;
  --radius: 14px;
  --gap: 12px;
  --gap-lg: 20px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body {
  margin: 0;
  padding: 0;
  width: 100%;
  height: 100%;
  background: var(--bg-0);
  color: var(--fg);
  font-family: var(--font);
  overflow: hidden;
  overscroll-behavior: none;
  touch-action: none;
  user-select: none;
  -webkit-user-select: none;
}
body {
  background:
    radial-gradient(120% 80% at 50% 0%, var(--bg-2) 0%, transparent 60%),
    radial-gradient(140% 120% at 50% 100%, var(--bg-1) 0%, var(--bg-0) 70%);
  background-attachment: fixed;
}

#app {
  position: fixed;
  inset: 0;
  width: 100%;
  height: 100%;
}

/* The canvas fills the whole app. */
#game-canvas {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  display: block;
  touch-action: none;
}

/* ==== Screens (menu overlays) ==== */
.screen {
  position: absolute;
  inset: 0;
  display: flex;
  flex-direction: column;
  padding: env(safe-area-inset-top, 0) env(safe-area-inset-right, 0)
           env(safe-area-inset-bottom, 0) env(safe-area-inset-left, 0);
  padding-top: max(env(safe-area-inset-top, 0), 16px);
  z-index: 10;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}
.screen[hidden] { display: none; }

.screen-header {
  display: flex;
  align-items: center;
  gap: var(--gap);
  padding: var(--gap);
}
.screen-header h2 {
  margin: 0;
  flex: 1;
  text-align: center;
  font-size: clamp(20px, 5vw, 28px);
  letter-spacing: 0.1em;
}

/* ==== Menu Card ==== */
.menu-card {
  margin: auto;
  width: min(440px, 92vw);
  padding: clamp(20px, 5vw, 36px);
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  display: flex;
  flex-direction: column;
  gap: var(--gap);
}
.title {
  margin: 0;
  text-align: center;
  font-size: clamp(36px, 11vw, 64px);
  font-weight: 900;
  letter-spacing: 0.04em;
  background: linear-gradient(180deg, #fff 0%, var(--accent) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.title-accent {
  background: linear-gradient(180deg, var(--accent) 0%, var(--accent-2) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}
.subtitle {
  margin: 0 0 var(--gap) 0;
  text-align: center;
  color: var(--fg-dim);
  font-size: clamp(13px, 3.5vw, 15px);
}

.menu-nav {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

/* ==== Buttons ==== */
.btn {
  appearance: none;
  border: 1px solid var(--card-border);
  background: rgba(255, 255, 255, 0.06);
  color: var(--fg);
  font-family: inherit;
  font-size: clamp(15px, 4vw, 17px);
  font-weight: 700;
  letter-spacing: 0.08em;
  padding: 14px 18px;
  min-height: var(--tap-min);
  border-radius: var(--radius);
  cursor: pointer;
  transition: transform 0.08s ease, background 0.15s ease, border-color 0.15s ease;
  text-align: center;
}
.btn:active {
  transform: scale(0.97);
}
.btn:focus-visible {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}
.btn-primary {
  background: linear-gradient(180deg, var(--accent) 0%, #2cb898 100%);
  color: #04231b;
  border-color: transparent;
}
.btn-ghost {
  background: transparent;
  color: var(--fg-dim);
}
.btn-back {
  flex: 0 0 auto;
  padding: 10px 14px;
  font-size: 14px;
  min-height: 40px;
}
.btn-danger {
  background: rgba(255, 59, 94, 0.15);
  border-color: rgba(255, 59, 94, 0.35);
  color: var(--danger);
}

/* ==== Coin badge ==== */
.coin-display {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  background: rgba(255, 255, 255, 0.06);
  border: 1px solid var(--card-border);
  border-radius: 999px;
  padding: 6px 14px;
  font-weight: 800;
  color: var(--warn);
  align-self: center;
  margin-top: var(--gap);
}
.coin-icon { color: var(--warn); }

/* ==== Level grid ==== */
.level-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(80px, 1fr));
  gap: 10px;
  padding: var(--gap);
}
.level-tile {
  aspect-ratio: 1 / 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  font-weight: 800;
  font-size: clamp(16px, 4vw, 20px);
  color: var(--fg);
  cursor: pointer;
  position: relative;
  min-height: var(--tap-min);
}
.level-tile.locked {
  opacity: 0.4;
  cursor: not-allowed;
}
.level-tile.cleared {
  background: rgba(79, 240, 197, 0.08);
  border-color: rgba(79, 240, 197, 0.4);
}
.level-tile .stars-row {
  font-size: 12px;
  color: var(--warn);
  letter-spacing: 2px;
  margin-top: 4px;
  min-height: 14px;
}
.level-tile .skip-cost {
  position: absolute;
  bottom: 4px;
  right: 6px;
  font-size: 9px;
  color: var(--warn);
}

/* ==== Tabs ==== */
.tab-row {
  display: flex;
  gap: 0;
  padding: 0 var(--gap);
  border-bottom: 1px solid var(--card-border);
}
.tab {
  flex: 1;
  appearance: none;
  background: transparent;
  border: none;
  color: var(--fg-dim);
  padding: 12px;
  font-family: inherit;
  font-weight: 700;
  cursor: pointer;
  border-bottom: 2px solid transparent;
  min-height: var(--tap-min);
}
.tab.is-active {
  color: var(--accent);
  border-bottom-color: var(--accent);
}

/* ==== Leaderboard ==== */
.leaderboard-content {
  padding: var(--gap);
}
.lb-row {
  display: grid;
  grid-template-columns: 30px 1fr 80px 80px;
  gap: 8px;
  align-items: center;
  padding: 10px 12px;
  background: rgba(255, 255, 255, 0.04);
  border-radius: 8px;
  margin-bottom: 6px;
  font-size: 14px;
}
.lb-row .lb-rank { color: var(--accent); font-weight: 800; }
.lb-row .lb-name { font-weight: 700; }
.lb-row .lb-score { text-align: right; }
.lb-row .lb-depth { text-align: right; color: var(--fg-dim); font-size: 12px; }
.lb-empty {
  color: var(--fg-dim);
  text-align: center;
  padding: 32px;
  font-size: 14px;
}

/* ==== Shop ==== */
.shop-sub {
  padding: 0 var(--gap);
  margin: var(--gap) 0 6px 0;
  color: var(--accent);
  font-size: 14px;
  letter-spacing: 0.1em;
}
.skin-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(120px, 1fr));
  gap: 10px;
  padding: var(--gap);
}
.skin-tile {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  padding: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  min-height: 130px;
  position: relative;
}
.skin-tile.owned { border-color: rgba(79, 240, 197, 0.4); }
.skin-tile.equipped {
  background: rgba(79, 240, 197, 0.12);
  border-color: var(--accent);
}
.skin-tile canvas {
  width: 56px;
  height: 56px;
}
.skin-tile .skin-name {
  font-weight: 700;
  font-size: 13px;
}
.skin-tile .skin-cost {
  font-size: 12px;
  color: var(--warn);
  font-weight: 700;
}
.skin-tile .skin-status {
  font-size: 11px;
  color: var(--accent);
  font-weight: 700;
  letter-spacing: 0.1em;
}

/* ==== Settings ==== */
.settings-list {
  padding: var(--gap);
  display: flex;
  flex-direction: column;
  gap: var(--gap);
}
.setting-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--gap);
  padding: 14px 16px;
  background: rgba(255, 255, 255, 0.04);
  border-radius: var(--radius);
  font-weight: 600;
  min-height: var(--tap-min);
}
.setting-row input[type="range"] {
  flex: 1;
  max-width: 60%;
  -webkit-appearance: none;
  appearance: none;
  height: 6px;
  background: rgba(255, 255, 255, 0.1);
  border-radius: 3px;
}
.setting-row input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  appearance: none;
  width: 22px;
  height: 22px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  box-shadow: 0 2px 8px rgba(79, 240, 197, 0.5);
}
.setting-row input[type="range"]::-moz-range-thumb {
  width: 22px;
  height: 22px;
  background: var(--accent);
  border-radius: 50%;
  cursor: pointer;
  border: none;
}
.setting-row input[type="checkbox"] {
  width: 24px;
  height: 24px;
  accent-color: var(--accent);
}

/* ==== Name entry ==== */
.name-entry {
  display: inline-flex;
  gap: 6px;
}
.name-letter {
  width: 36px;
  height: 44px;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  color: var(--fg);
  font-family: inherit;
  font-size: 22px;
  font-weight: 800;
  text-align: center;
  appearance: none;
  cursor: pointer;
}
.name-letter:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

/* ==== How-to & credits body ==== */
.howto-body {
  padding: var(--gap-lg);
  max-width: 480px;
  margin: 0 auto;
  font-size: clamp(14px, 4vw, 16px);
  line-height: 1.6;
  color: var(--fg-dim);
}
.howto-body strong { color: var(--fg); }
.kw-safe { color: var(--safe); font-weight: 800; }
.kw-kill { color: var(--danger); font-weight: 800; }
kbd {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid var(--card-border);
  border-radius: 4px;
  padding: 2px 6px;
  font-family: monospace;
  font-size: 0.9em;
  color: var(--fg);
}

/* ==== HUD ==== */
.hud {
  position: absolute;
  inset: 0;
  pointer-events: none;
  z-index: 5;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  padding: max(env(safe-area-inset-top, 0), 12px) 12px
           max(env(safe-area-inset-bottom, 0), 12px) 12px;
}
.hud[hidden] { display: none; }
.hud-top {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  pointer-events: none;
}
.hud-btn {
  pointer-events: auto;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: rgba(15, 18, 50, 0.7);
  border: 1px solid var(--card-border);
  color: var(--fg);
  font-weight: 800;
  font-size: 16px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}
.hud-stats {
  flex: 1;
  display: flex;
  gap: 10px;
  justify-content: center;
  flex-wrap: wrap;
}
.hud-stat {
  background: rgba(15, 18, 50, 0.7);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 6px 12px;
  text-align: center;
  min-width: 56px;
}
.hud-label {
  display: block;
  font-size: 9px;
  letter-spacing: 0.15em;
  color: var(--fg-dim);
  font-weight: 700;
}
.hud-stat > span:last-child {
  font-size: 18px;
  font-weight: 800;
  color: var(--accent);
}
#hud-combo { color: var(--accent-2); }

.hud-touch-buttons {
  display: flex;
  justify-content: space-between;
  pointer-events: none;
  gap: 12px;
}
.hud-rot {
  pointer-events: auto;
  width: 64px;
  height: 64px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--card-border);
  color: var(--fg);
  font-size: 22px;
  font-weight: 800;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  opacity: 0.5;
}
.hud-rot:active { opacity: 1; background: rgba(79, 240, 197, 0.2); }

@media (min-width: 720px) {
  .hud-touch-buttons { display: none; }
}

/* ==== Overlays ==== */
.overlay {
  position: absolute;
  inset: 0;
  background: rgba(7, 8, 28, 0.75);
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 16px;
}
.overlay[hidden] { display: none; }
.overlay-card {
  width: min(380px, 92vw);
  padding: clamp(20px, 5vw, 32px);
  background: var(--card);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  display: flex;
  flex-direction: column;
  gap: 12px;
  text-align: center;
}
.overlay-card h2 {
  margin: 0;
  font-size: clamp(24px, 7vw, 36px);
  letter-spacing: 0.1em;
}
.result-stats {
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 12px;
  background: rgba(0, 0, 0, 0.3);
  border-radius: 10px;
}
.result-row {
  display: flex;
  justify-content: space-between;
  font-weight: 700;
}
.result-row span:first-child { color: var(--fg-dim); }
.result-row span:last-child { color: var(--accent); }
.newbest {
  font-weight: 900;
  color: var(--accent-2);
  font-size: 18px;
  letter-spacing: 0.15em;
  animation: pulse 1s ease-in-out infinite;
}
@keyframes pulse { 50% { opacity: 0.5; } }
.stars {
  font-size: 36px;
  color: var(--warn);
  letter-spacing: 8px;
}
.stars .empty { color: rgba(255, 181, 71, 0.2); }
.enter-name {
  margin: 0;
  font-size: 13px;
  color: var(--fg-dim);
  letter-spacing: 0.1em;
}

/* ==== Achievement popup ==== */
.achievement-pop {
  position: absolute;
  top: max(env(safe-area-inset-top, 0), 16px);
  left: 50%;
  transform: translateX(-50%);
  background: var(--card);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  padding: 12px 18px;
  display: flex;
  align-items: center;
  gap: 12px;
  z-index: 30;
  box-shadow: 0 4px 16px rgba(79, 240, 197, 0.3);
  animation: ach-slide 3s ease forwards;
}
.achievement-pop[hidden] { display: none; }
.ach-icon {
  font-size: 28px;
  color: var(--warn);
}
.ach-title {
  font-size: 10px;
  letter-spacing: 0.15em;
  color: var(--fg-dim);
}
.ach-name { font-weight: 800; }
@keyframes ach-slide {
  0% { transform: translate(-50%, -100px); opacity: 0; }
  10%, 80% { transform: translate(-50%, 0); opacity: 1; }
  100% { transform: translate(-50%, -100px); opacity: 0; }
}

/* ==== Toast ==== */
.toast {
  position: absolute;
  bottom: 20%;
  left: 50%;
  transform: translateX(-50%);
  background: rgba(0, 0, 0, 0.8);
  border: 1px solid var(--card-border);
  border-radius: 999px;
  padding: 10px 18px;
  font-weight: 700;
  color: var(--fg);
  z-index: 40;
  pointer-events: none;
  animation: toast-fade 2.2s ease forwards;
}
.toast[hidden] { display: none; }
@keyframes toast-fade {
  0%, 80% { opacity: 1; }
  100% { opacity: 0; }
}

/* ==== Tablet / desktop tweaks ==== */
@media (min-width: 720px) {
  .menu-card { width: min(420px, 50vw); }
  .level-grid { grid-template-columns: repeat(auto-fill, minmax(96px, 1fr)); }
}

/* ==== LIGHT THEME ==== */
:root[data-theme="light"] {
  --bg-0: #f6f6fb;
  --bg-1: #e9ebf5;
  --bg-2: #dadeed;
  --fg: #15192e;
  --fg-dim: #5b6280;
  --card: rgba(255, 255, 255, 0.92);
  --card-border: rgba(15, 18, 40, 0.08);
  --shadow: 0 8px 32px rgba(15, 18, 40, 0.12);
}
:root[data-theme="light"] body {
  background:
    radial-gradient(120% 80% at 50% 0%, var(--bg-2) 0%, transparent 60%),
    radial-gradient(140% 120% at 50% 100%, var(--bg-1) 0%, var(--bg-0) 70%);
}
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg-0: #f6f6fb;
    --bg-1: #e9ebf5;
    --bg-2: #dadeed;
    --fg: #15192e;
    --fg-dim: #5b6280;
    --card: rgba(255, 255, 255, 0.92);
    --card-border: rgba(15, 18, 40, 0.08);
    --shadow: 0 8px 32px rgba(15, 18, 40, 0.12);
  }
}