/**
 * BlockShift 3D — Main Stylesheet
 * @version 1.0.0
 * @author codavax
 * @license Commercial License — CodeCanyon / Envato Market
 * @copyright (c) 2026 codavax. All rights reserved.
 *
 * Design System: "Midnight Tech" with Liquid Glass UI
 * Naming: BEM (Block__Element--Modifier)
 * Units: rem/em/% for responsive, px only for borders/shadows
 */

/* ==========================================================================
   1. CSS CUSTOM PROPERTIES (Design Tokens)
   ========================================================================== */

:root {
  /* ── Color Palette: Midnight Tech ── */
  --color-bg-deep: #0f172a;
  --color-bg-surface: #1e293b;
  --color-bg-elevated: #334155;

  --color-text-primary: #f8fafc;
  --color-text-secondary: #94a3b8;
  --color-text-muted: #64748b;

  --color-accent-orange: #f97316;
  --color-accent-emerald: #10b981;
  --color-accent-rose: #e11d48;
  --color-accent-cyan: #06b6d4;

  --color-tile-base: #334155;
  --color-tile-goal: #10b981;
  --color-tile-danger: #e11d48;
  --color-tile-switch: #06b6d4;
  --color-tile-bridge: #8b5cf6;

  --color-block: #f97316;
  --color-block-glow: rgba(249, 115, 22, 0.5);

  /* ── Glass Effect ── */
  --glass-bg: rgba(30, 41, 59, 0.7);
  --glass-border: rgba(148, 163, 184, 0.15);
  --glass-blur: 16px;
  --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);

  /* ── Typography ── */
  --font-display: "Outfit", sans-serif;
  --font-mono: "Space Mono", monospace;
  --font-fallback:
    -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;

  /* ── Spacing Scale ── */
  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* ── Border Radius ── */
  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;
  --radius-pill: 9999px;

  /* ── Transitions ── */
  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --duration-fast: 150ms;
  --duration-normal: 300ms;
  --duration-slow: 500ms;

  /* ── Z-Index Scale ── */
  --z-canvas: 1;
  --z-hud: 10;
  --z-overlay: 100;
  --z-header: 200;
  --z-modal: 1000;
}

/* ==========================================================================
   2. BASE STYLES
   ========================================================================== */

*,
*::before,
*::after {
  -webkit-box-sizing: border-box;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: var(--font-display), var(--font-fallback);
  background-color: var(--color-bg-deep);
  color: var(--color-text-primary);
  min-height: 100vh;
  overflow: hidden;
  -webkit-user-select: none;
  -moz-user-select: none;
  -ms-user-select: none;
  user-select: none;
  overscroll-behavior: none;
  cursor: default;
}

/* Mesh Gradient Background */
body::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background:
    radial-gradient(
      ellipse at 20% 50%,
      rgba(6, 182, 212, 0.08) 0%,
      transparent 50%
    ),
    radial-gradient(
      ellipse at 80% 20%,
      rgba(249, 115, 22, 0.06) 0%,
      transparent 50%
    ),
    radial-gradient(
      ellipse at 50% 80%,
      rgba(139, 92, 246, 0.06) 0%,
      transparent 50%
    );
  pointer-events: none;
  z-index: 0;
}

/* ==========================================================================
   3. GAME LAYOUT
   ========================================================================== */

.game-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: justify;
  -ms-flex-pack: justify;
  justify-content: space-between;
  padding: var(--space-sm) var(--space-lg);
  z-index: var(--z-header);
  pointer-events: none;
}

.game-header__title {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  color: var(--color-text-secondary);
  margin: 0;
  opacity: 0.6;
  text-transform: uppercase;
}

.menu__title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 8vw, 5rem);
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
  margin: 0;
  line-height: 1;
  text-shadow: 0 0 40px var(--color-block-glow);
  text-transform: uppercase;
}

.hud__title {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 800;
  letter-spacing: 0.05em;
  color: var(--color-text-secondary);
  margin-left: var(--space-md);
  text-transform: uppercase;
}

.game-header__nav {
  pointer-events: auto;
}

.game-header__btn {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  color: var(--color-text-primary);
  width: 2.5rem;
  height: 2.5rem;
  border-radius: var(--radius-md);
  cursor: pointer;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  -webkit-transition:
    background var(--duration-fast) var(--ease-out),
    -webkit-transform var(--duration-fast) var(--ease-spring);
  transition:
    background var(--duration-fast) var(--ease-out),
    transform var(--duration-fast) var(--ease-spring);
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
}

.game-header__btn:hover {
  background: rgba(148, 163, 184, 0.2);
  -webkit-transform: scale(1.1);
  transform: scale(1.1);
}

.game-header__btn:active {
  -webkit-transform: scale(0.95);
  transform: scale(0.95);
}

.game-header__btn-icon {
  font-size: 1.125rem;
  line-height: 1;
}

.game-main {
  position: relative;
  width: 100vw;
  height: 100vh;
  z-index: var(--z-canvas);
}

/* ==========================================================================
   4. CANVAS
   ========================================================================== */

.game-canvas {
  display: block;
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  cursor: crosshair;
}

/* Custom cursor feedback when hovering interactive areas (RULE-DESIGN-007) */
.game-canvas:active {
  cursor: -webkit-grabbing;
  cursor: grabbing;
}

/* ==========================================================================
   5. OVERLAY CONTAINER
   ========================================================================== */

.game-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: var(--z-overlay);
  pointer-events: none;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
}

/* ==========================================================================
   6. MENU SCREEN
   ========================================================================== */

.menu {
  pointer-events: auto;
  text-align: center;
  -webkit-animation: fadeSlideUp var(--duration-slow) var(--ease-out) both;
  animation: fadeSlideUp var(--duration-slow) var(--ease-out) both;
}

.menu--hidden {
  display: none;
}

.menu__logo {
  margin-bottom: var(--space-3xl);
}

.menu__title {
  font-family: var(--font-display);
  font-size: clamp(2.5rem, 8vw, 5rem);
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
  margin: 0;
  line-height: 1;
  text-shadow: 0 0 40px var(--color-block-glow);
}

.menu__subtitle {
  display: block;
  font-family: var(--font-mono);
  font-size: clamp(1rem, 3vw, 1.5rem);
  font-weight: 700;
  color: var(--color-accent-orange);
  letter-spacing: 0.3em;
  margin-top: var(--space-xs);
}

.menu__actions {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -ms-flex-direction: column;
  flex-direction: column;
  gap: var(--space-lg);
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
}

/* ==========================================================================
   7. BUTTONS
   ========================================================================== */

.btn {
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: var(--space-md) var(--space-2xl);
  border: 2px solid transparent;
  border-radius: var(--radius-pill);
  cursor: pointer;
  min-width: 14rem;
  -webkit-transition: all var(--duration-normal) var(--ease-out);
  transition: all var(--duration-normal) var(--ease-out);
  position: relative;
  overflow: hidden;
  -webkit-box-shadow: 0 4px 24px rgba(249, 115, 22, 0.15);
  box-shadow: 0 4px 24px rgba(249, 115, 22, 0.15);
}

.btn::after {
  content: "";
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: -webkit-linear-gradient(
    left,
    transparent,
    rgba(255, 255, 255, 0.08),
    transparent
  );
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.08),
    transparent
  );
  -webkit-transition: left var(--duration-slow) var(--ease-out);
  transition: left var(--duration-slow) var(--ease-out);
}

.btn:hover::after {
  left: 100%;
}

/* ── All menu buttons share the same gradient style ── */
.btn--primary,
.btn--secondary {
  background: -webkit-linear-gradient(
    135deg,
    var(--color-accent-orange),
    #ea580c
  );
  background: linear-gradient(135deg, var(--color-accent-orange), #ea580c);
  color: var(--color-text-primary);
  border-color: var(--color-accent-orange);
}

.btn--primary:hover,
.btn--secondary:hover {
  border-color: var(--color-accent-orange);
  -webkit-box-shadow:
    0 0 0 4px var(--color-bg-deep),
    0 0 0 6px var(--color-accent-orange),
    0 8px 32px rgba(249, 115, 22, 0.5);
  box-shadow:
    0 0 0 4px var(--color-bg-deep),
    0 0 0 6px var(--color-accent-orange),
    0 8px 32px rgba(249, 115, 22, 0.5);
  -webkit-transform: translateY(-2px);
  transform: translateY(-2px);
}

.btn--primary:active,
.btn--secondary:active {
  -webkit-transform: translateY(0);
  transform: translateY(0);
}

.btn--back {
  background: transparent;
  color: var(--color-text-secondary);
  border-color: transparent;
  min-width: auto;
  padding: var(--space-sm) var(--space-lg);
  font-size: 0.875rem;
  -webkit-box-shadow: none;
  box-shadow: none;
}

.btn--back:hover {
  color: var(--color-text-primary);
  -webkit-box-shadow: none;
  box-shadow: none;
}

/* ==========================================================================
   7b. LOADING SCREEN
   ========================================================================== */

.loading {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  background: var(--color-bg-deep);
  z-index: var(--z-overlay);
  pointer-events: auto;
  opacity: 0;
  visibility: hidden;
  -webkit-transition: opacity var(--duration-normal) var(--ease-out);
  transition: opacity var(--duration-normal) var(--ease-out);
}

.loading--visible {
  opacity: 1;
  visibility: visible;
}

/* ── 3D Rotating Block ── */
.loading__scene {
  width: 3.5rem;
  height: 3.5rem;
  -webkit-perspective: 600px;
  perspective: 600px;
  margin-bottom: var(--space-xl);
}

.loading__cube {
  width: 100%;
  height: 100%;
  position: relative;
  -webkit-transform-style: preserve-3d;
  transform-style: preserve-3d;
  -webkit-animation: cubeRotate 2s linear infinite;
  animation: cubeRotate 2s linear infinite;
}

.loading__face {
  position: absolute;
  width: 3.5rem;
  height: 3.5rem;
  border: 2px solid rgba(249, 115, 22, 0.6);
  background: -webkit-linear-gradient(
    135deg,
    var(--color-accent-orange),
    #ea580c
  );
  background: linear-gradient(135deg, var(--color-accent-orange), #ea580c);
  opacity: 0.9;
}

.loading__face--front {
  -webkit-transform: translateZ(1.75rem);
  transform: translateZ(1.75rem);
}
.loading__face--back {
  -webkit-transform: rotateY(180deg) translateZ(1.75rem);
  transform: rotateY(180deg) translateZ(1.75rem);
}
.loading__face--right {
  -webkit-transform: rotateY(90deg) translateZ(1.75rem);
  transform: rotateY(90deg) translateZ(1.75rem);
}
.loading__face--left {
  -webkit-transform: rotateY(-90deg) translateZ(1.75rem);
  transform: rotateY(-90deg) translateZ(1.75rem);
}
.loading__face--top {
  -webkit-transform: rotateX(90deg) translateZ(1.75rem);
  transform: rotateX(90deg) translateZ(1.75rem);
}
.loading__face--bottom {
  -webkit-transform: rotateX(-90deg) translateZ(1.75rem);
  transform: rotateX(-90deg) translateZ(1.75rem);
}

@-webkit-keyframes cubeRotate {
  0% {
    -webkit-transform: rotateX(-20deg) rotateY(0deg);
  }
  100% {
    -webkit-transform: rotateX(-20deg) rotateY(360deg);
  }
}

@keyframes cubeRotate {
  0% {
    -webkit-transform: rotateX(-20deg) rotateY(0deg);
    transform: rotateX(-20deg) rotateY(0deg);
  }
  100% {
    -webkit-transform: rotateX(-20deg) rotateY(360deg);
    transform: rotateX(-20deg) rotateY(360deg);
  }
}

/* ── Progress Bar ── */
.loading__bar {
  width: min(80%, 22rem);
  height: 0.375rem;
  background: var(--color-bg-elevated);
  border-radius: var(--radius-pill);
  overflow: hidden;
  margin-bottom: var(--space-md);
}

.loading__fill {
  width: 0;
  height: 100%;
  background: -webkit-linear-gradient(
    90deg,
    var(--color-accent-orange),
    #ea580c
  );
  background: linear-gradient(90deg, var(--color-accent-orange), #ea580c);
  border-radius: var(--radius-pill);
  -webkit-animation: loadFill 2.2s var(--ease-out) forwards;
  animation: loadFill 2.2s var(--ease-out) forwards;
}

@-webkit-keyframes loadFill {
  0% {
    width: 0;
  }
  60% {
    width: 75%;
  }
  100% {
    width: 100%;
  }
}

@keyframes loadFill {
  0% {
    width: 0;
  }
  60% {
    width: 75%;
  }
  100% {
    width: 100%;
  }
}

/* ── Loading Text ── */
.loading__text {
  font-family: var(--font-display);
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

/* ── Start Button (appears after loading) ── */
.loading__start {
  margin-top: var(--space-xl);
  font-family: var(--font-display);
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  padding: var(--space-md) var(--space-2xl);
  border: 2px solid var(--color-accent-orange);
  border-radius: var(--radius-pill);
  cursor: pointer;
  min-width: 12rem;
  background: -webkit-linear-gradient(
    135deg,
    var(--color-accent-orange),
    #ea580c
  );
  background: linear-gradient(135deg, var(--color-accent-orange), #ea580c);
  color: var(--color-text-primary);
  -webkit-box-shadow:
    0 0 0 4px var(--color-bg-deep),
    0 0 0 6px var(--color-accent-orange),
    0 4px 24px rgba(249, 115, 22, 0.25);
  box-shadow:
    0 0 0 4px var(--color-bg-deep),
    0 0 0 6px var(--color-accent-orange),
    0 4px 24px rgba(249, 115, 22, 0.25);
  opacity: 0;
  visibility: hidden;
  -webkit-transform: translateY(0.5rem);
  transform: translateY(0.5rem);
  -webkit-transition:
    opacity var(--duration-normal) var(--ease-out),
    visibility var(--duration-normal) var(--ease-out),
    -webkit-transform var(--duration-normal) var(--ease-out),
    -webkit-box-shadow var(--duration-fast) var(--ease-out);
  transition:
    opacity var(--duration-normal) var(--ease-out),
    visibility var(--duration-normal) var(--ease-out),
    transform var(--duration-normal) var(--ease-out),
    box-shadow var(--duration-fast) var(--ease-out);
}

.loading__start--visible {
  opacity: 1;
  visibility: visible;
  -webkit-transform: translateY(0);
  transform: translateY(0);
}

.loading__start:hover {
  -webkit-box-shadow:
    0 0 0 4px var(--color-bg-deep),
    0 0 0 6px var(--color-accent-orange),
    0 8px 32px rgba(249, 115, 22, 0.5);
  box-shadow:
    0 0 0 4px var(--color-bg-deep),
    0 0 0 6px var(--color-accent-orange),
    0 8px 32px rgba(249, 115, 22, 0.5);
  -webkit-transform: translateY(-2px);
  transform: translateY(-2px);
}

.loading__start:active {
  -webkit-transform: translateY(0);
  transform: translateY(0);
}

/* ==========================================================================
   7c. GAMEPLAY INSTRUCTIONS
   ========================================================================== */

.menu__controls {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  gap: var(--space-xl);
  margin-top: var(--space-2xl);
  padding-top: var(--space-lg);
  border-top: 1px solid var(--glass-border);
}

.menu__control-item {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  gap: var(--space-xs);
}

.menu__control-icon {
  font-size: 1.5rem;
  line-height: 1;
}

.menu__control-label {
  font-family: var(--font-mono);
  font-size: 0.625rem;
  color: var(--color-text-muted);
  letter-spacing: 0.06em;
  text-transform: uppercase;
  white-space: nowrap;
}

/* ==========================================================================
   7d. IN-GAME HELP OVERLAY
   ========================================================================== */

.help-overlay {
  position: absolute;
  top: var(--space-3xl);
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  z-index: var(--z-modal);
  pointer-events: auto;
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg) var(--space-xl);
  max-width: 22rem;
  width: 90%;
  text-align: center;
  opacity: 0;
  visibility: hidden;
  -webkit-transition:
    opacity var(--duration-normal) var(--ease-out),
    visibility var(--duration-normal) var(--ease-out);
  transition:
    opacity var(--duration-normal) var(--ease-out),
    visibility var(--duration-normal) var(--ease-out);
}

.help-overlay--visible {
  opacity: 1;
  visibility: visible;
}

.help-overlay__title {
  font-family: var(--font-display);
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--color-accent-orange);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin: 0 0 var(--space-sm) 0;
}

.help-overlay__text {
  font-family: var(--font-display);
  font-size: 0.8125rem;
  font-weight: 400;
  color: var(--color-text-secondary);
  line-height: 1.6;
  margin: 0 0 var(--space-xs) 0;
}

.help-overlay__goal {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-accent-emerald);
  margin: var(--space-sm) 0 var(--space-md) 0;
}

.help-overlay__dismiss {
  font-family: var(--font-display);
  font-size: 0.6875rem;
  font-weight: 600;
  color: var(--color-text-muted);
  background: transparent;
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-pill);
  padding: var(--space-xs) var(--space-lg);
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  -webkit-transition: color var(--duration-fast) var(--ease-out);
  transition: color var(--duration-fast) var(--ease-out);
}

.help-overlay__dismiss:hover {
  color: var(--color-text-primary);
}

/* ==========================================================================
   8. STAGE INTRO SCREEN
   ========================================================================== */

.stage-intro {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  display: none;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  background: var(--color-bg-deep);
  pointer-events: auto;
  z-index: var(--z-modal);
}

.stage-intro--visible {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
}

.stage-intro__title {
  font-family: var(--font-display);
  font-size: clamp(3rem, 12vw, 8rem);
  font-weight: 900;
  letter-spacing: -0.02em;
  color: var(--color-text-primary);
  margin: 0;
  text-shadow: 0 0 60px var(--color-block-glow);
  text-transform: uppercase;
  -webkit-animation: stageIntroZoom 1.8s var(--ease-out) both;
  animation: stageIntroZoom 1.8s var(--ease-out) both;
}

/* ==========================================================================
   8a. PAUSE MENU
   ========================================================================== */

.pause-menu {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: var(--z-overlay);
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  background: rgba(15, 23, 42, 0.4);
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
  -webkit-transition:
    opacity var(--duration-normal) var(--ease-out),
    visibility var(--duration-normal) var(--ease-out);
  transition:
    opacity var(--duration-normal) var(--ease-out),
    visibility var(--duration-normal) var(--ease-out);
}

.pause-menu--visible {
  opacity: 1;
  visibility: visible;
  pointer-events: auto;
}

.pause-menu__content {
  text-align: center;
  max-width: 24rem;
  width: 90%;
  -webkit-animation: fadeSlideUp var(--duration-normal) var(--ease-out) both;
  animation: fadeSlideUp var(--duration-normal) var(--ease-out) both;
}

.pause-menu__title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 3rem);
  font-weight: 900;
  color: var(--color-text-primary);
  margin-bottom: var(--space-2xl);
  text-shadow: 0 0 30px var(--color-block-glow);
  text-transform: uppercase;
  letter-spacing: 0.1em;
}

.pause-menu__actions {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-orient: vertical;
  -ms-flex-direction: column;
  flex-direction: column;
  gap: var(--space-lg);
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
}

.pause-menu__audio {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  gap: var(--space-md);
  width: 100%;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
}

.btn--audio {
  min-width: 8rem;
  font-size: 0.75rem;
  padding: var(--space-sm) var(--space-lg);
}

/* ==========================================================================
   9. LEVEL SELECT SCREEN
   ========================================================================== */

.level-select {
  display: none;
  -webkit-box-orient: vertical;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  gap: var(--space-xl);
  padding: var(--space-xl);
  pointer-events: auto;
  max-height: 85vh;
  overflow-y: auto;
}

.level-select--visible {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
}

.level-select__title {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--color-text-primary);
  margin: 0;
}

.level-select__grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(4rem, 1fr));
  gap: var(--space-sm);
  width: 100%;
  max-width: 28rem;
}

.level-select__cell {
  aspect-ratio: 1;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  font-family: var(--font-mono);
  font-size: 0.875rem;
  font-weight: 700;
  border-radius: var(--radius-md);
  border: 1px solid var(--glass-border);
  background: var(--glass-bg);
  color: var(--color-text-secondary);
  cursor: pointer;
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  -webkit-transition: all var(--duration-fast) var(--ease-out);
  transition: all var(--duration-fast) var(--ease-out);
}

.level-select__cell:hover {
  background: rgba(148, 163, 184, 0.25);
  -webkit-transform: scale(1.08);
  transform: scale(1.08);
  color: var(--color-text-primary);
}

.level-select__cell--complete {
  border-color: var(--color-accent-emerald);
  color: var(--color-accent-emerald);
}

.level-select__cell--locked {
  opacity: 0.35;
  cursor: not-allowed;
  pointer-events: none;
}

.level-select__cell--current {
  border-color: var(--color-accent-orange);
  color: var(--color-accent-orange);
  -webkit-box-shadow: 0 0 16px rgba(249, 115, 22, 0.3);
  box-shadow: 0 0 16px rgba(249, 115, 22, 0.3);
}

/* ==========================================================================
   10. SETTINGS SCREEN
   ========================================================================== */

.settings {
  display: none;
  -webkit-box-orient: vertical;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  gap: var(--space-xl);
  pointer-events: auto;
  padding: var(--space-xl);
}

.settings--visible {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
}

.settings__title {
  font-family: var(--font-display);
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--color-text-primary);
  margin: 0;
}

.settings__group {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-xl);
  padding: var(--space-lg);
  width: 100%;
  max-width: 20rem;
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  -webkit-box-shadow: var(--glass-shadow);
  box-shadow: var(--glass-shadow);
}

.settings__row {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: justify;
  -ms-flex-pack: justify;
  justify-content: space-between;
  padding: var(--space-md) 0;
  border-bottom: 1px solid rgba(148, 163, 184, 0.1);
}

.settings__row:last-child {
  border-bottom: none;
}

.settings__label {
  font-family: var(--font-display);
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--color-text-secondary);
}

.settings__toggle {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  padding: var(--space-xs) var(--space-md);
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-accent-emerald);
  background: rgba(16, 185, 129, 0.15);
  color: var(--color-accent-emerald);
  cursor: pointer;
  -webkit-transition: all var(--duration-fast) var(--ease-out);
  transition: all var(--duration-fast) var(--ease-out);
}

.settings__toggle--off {
  border-color: var(--color-text-muted);
  background: transparent;
  color: var(--color-text-muted);
}

.settings__input {
  font-family: var(--font-mono);
  font-size: 1.125rem;
  letter-spacing: 0.3em;
  text-align: center;
  width: 6rem;
  padding: var(--space-xs) var(--space-sm);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  background: rgba(15, 23, 42, 0.6);
  color: var(--color-text-primary);
  outline: none;
  -webkit-transition: border-color var(--duration-fast) var(--ease-out);
  transition: border-color var(--duration-fast) var(--ease-out);
}

.settings__input:focus {
  border-color: var(--color-accent-cyan);
}

/* ==========================================================================
   11. STAGE COMPLETE SCREEN
   ========================================================================== */

.stage-complete {
  display: none;
  -webkit-box-orient: vertical;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  gap: var(--space-xl);
  text-align: center;
  pointer-events: auto;
}

.stage-complete--visible {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-animation: fadeSlideUp var(--duration-slow) var(--ease-out) both;
  animation: fadeSlideUp var(--duration-slow) var(--ease-out) both;
}

.stage-complete__title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 3.5rem);
  font-weight: 900;
  color: var(--color-accent-emerald);
  margin: 0;
  text-shadow: 0 0 40px rgba(16, 185, 129, 0.4);
}

.stage-complete__message {
  font-family: var(--font-display);
  font-size: 1rem;
  color: var(--color-text-secondary);
  margin: 0;
}

/* ==========================================================================
   12. GAME OVER SCREEN
   ========================================================================== */

.game-over {
  display: none;
  -webkit-box-orient: vertical;
  -ms-flex-direction: column;
  flex-direction: column;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  gap: var(--space-xl);
  text-align: center;
  pointer-events: auto;
}

.game-over--visible {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-animation: shakeIn 0.6s var(--ease-out) both;
  animation: shakeIn 0.6s var(--ease-out) both;
}

.game-over__title {
  font-family: var(--font-display);
  font-size: clamp(2rem, 6vw, 3.5rem);
  font-weight: 900;
  color: var(--color-accent-rose);
  margin: 0;
  text-shadow: 0 0 40px rgba(225, 29, 72, 0.4);
}

/* ==========================================================================
   13. HUD (Heads-Up Display)
   ========================================================================== */

.hud {
  display: none;
  position: absolute;
  top: var(--space-md);
  left: var(--space-md);
  right: var(--space-md);
  padding: var(--space-sm) var(--space-md);
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: justify;
  -ms-flex-pack: justify;
  justify-content: space-between;
  pointer-events: none;
  z-index: var(--z-hud);
}

.hud--visible {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
}

.hud--visible ~ .game-header,
.game-header--hidden {
  display: none;
}

.hud__left {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  gap: 0.75rem;
}

.hud__menu-btn {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--color-text-primary);
  background: var(--glass-bg);
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 0.5rem 1rem;
  cursor: pointer;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  pointer-events: auto;
  -webkit-transition: all var(--duration-fast) var(--ease-out);
  transition: all var(--duration-fast) var(--ease-out);
  -webkit-box-shadow: var(--glass-shadow);
  box-shadow: var(--glass-shadow);
}

.hud__menu-btn:hover {
  color: var(--color-accent-orange);
  background: rgba(148, 163, 184, 0.2);
  border-color: rgba(249, 115, 22, 0.3);
}

.hud__menu-btn:active {
  -webkit-transform: scale(0.95);
  transform: scale(0.95);
}

.hud__title {
  font-family: var(--font-display);
  font-size: 1.125rem;
  font-weight: 800;
  letter-spacing: 0.06em;
  color: var(--color-text-secondary);
  opacity: 0.75;
}

.hud__info {
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  gap: var(--space-sm);
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
}

.hud__passcode,
.hud__stage,
.hud__moves {
  font-family: var(--font-mono);
  font-size: 0.8125rem;
  font-weight: 700;
  color: var(--color-text-primary);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  padding: 0.5rem 1rem;
  border-radius: 1.25rem;
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  white-space: nowrap;
}

.hud__audio-btn {
  font-size: 1.125rem;
  line-height: 1;
  color: var(--color-text-primary);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 50%;
  -webkit-backdrop-filter: blur(var(--glass-blur));
  backdrop-filter: blur(var(--glass-blur));
  cursor: pointer;
  pointer-events: auto;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  -webkit-transition: all var(--duration-fast) var(--ease-out);
  transition: all var(--duration-fast) var(--ease-out);
}

.hud__audio-btn:hover {
  background: rgba(148, 163, 184, 0.25);
  -webkit-transform: scale(1.1);
  transform: scale(1.1);
}

.hud__audio-btn:active {
  -webkit-transform: scale(0.92);
  transform: scale(0.92);
}

/* ==========================================================================
   14. MOBILE D-PAD
   ========================================================================== */

.dpad {
  display: none;
  position: absolute;
  bottom: var(--space-3xl);
  left: 50%;
  -webkit-transform: translateX(-50%);
  transform: translateX(-50%);
  z-index: var(--z-hud);
  pointer-events: auto;
}

.dpad--visible {
  display: grid;
  grid-template-columns: repeat(3, 3.5rem);
  grid-template-rows: repeat(3, 3.5rem);
  gap: var(--space-xs);
}

.dpad__btn {
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  color: var(--color-text-secondary);
  font-size: 1.25rem;
  cursor: pointer;
  display: -webkit-box;
  display: -ms-flexbox;
  display: flex;
  -webkit-box-align: center;
  -ms-flex-align: center;
  align-items: center;
  -webkit-box-pack: center;
  -ms-flex-pack: center;
  justify-content: center;
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
  -webkit-transition: background var(--duration-fast) var(--ease-out);
  transition: background var(--duration-fast) var(--ease-out);
  -webkit-tap-highlight-color: transparent;
}

.dpad__btn:active {
  background: rgba(249, 115, 22, 0.3);
  color: var(--color-accent-orange);
}

.dpad__btn--up {
  grid-column: 2;
  grid-row: 1;
}
.dpad__btn--left {
  grid-column: 1;
  grid-row: 2;
}
.dpad__btn--right {
  grid-column: 3;
  grid-row: 2;
}
.dpad__btn--down {
  grid-column: 2;
  grid-row: 3;
}

/* ==========================================================================
   15. FOOTER
   ========================================================================== */

/* ==========================================================================
   16. KEYFRAME ANIMATIONS
   ========================================================================== */

@-webkit-keyframes fadeSlideUp {
  from {
    opacity: 0;
    -webkit-transform: translateY(2rem);
    transform: translateY(2rem);
  }
  to {
    opacity: 1;
    -webkit-transform: translateY(0);
    transform: translateY(0);
  }
}

@keyframes fadeSlideUp {
  from {
    opacity: 0;
    transform: translateY(2rem);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@-webkit-keyframes stageIntroZoom {
  0% {
    opacity: 0;
    -webkit-transform: scale(0.3);
    transform: scale(0.3);
  }
  50% {
    opacity: 1;
    -webkit-transform: scale(1.05);
    transform: scale(1.05);
  }
  70% {
    -webkit-transform: scale(0.98);
    transform: scale(0.98);
  }
  85% {
    opacity: 1;
    -webkit-transform: scale(1);
    transform: scale(1);
  }
  100% {
    opacity: 0;
    -webkit-transform: scale(1.5);
    transform: scale(1.5);
  }
}

@keyframes stageIntroZoom {
  0% {
    opacity: 0;
    transform: scale(0.3);
  }
  50% {
    opacity: 1;
    transform: scale(1.05);
  }
  70% {
    transform: scale(0.98);
  }
  85% {
    opacity: 1;
    transform: scale(1);
  }
  100% {
    opacity: 0;
    transform: scale(1.5);
  }
}

@-webkit-keyframes shakeIn {
  0% {
    opacity: 0;
    -webkit-transform: translateX(-1rem);
    transform: translateX(-1rem);
  }
  25% {
    -webkit-transform: translateX(0.75rem);
    transform: translateX(0.75rem);
  }
  50% {
    -webkit-transform: translateX(-0.5rem);
    transform: translateX(-0.5rem);
  }
  75% {
    -webkit-transform: translateX(0.25rem);
    transform: translateX(0.25rem);
  }
  100% {
    opacity: 1;
    -webkit-transform: translateX(0);
    transform: translateX(0);
  }
}

@keyframes shakeIn {
  0% {
    opacity: 0;
    transform: translateX(-1rem);
  }
  25% {
    transform: translateX(0.75rem);
  }
  50% {
    transform: translateX(-0.5rem);
  }
  75% {
    transform: translateX(0.25rem);
  }
  100% {
    opacity: 1;
    transform: translateX(0);
  }
}

@-webkit-keyframes pulse {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.6;
  }
}

@keyframes pulse {
  0%,
  100% {
    opacity: 1;
  }
  50% {
    opacity: 0.6;
  }
}

/* ==========================================================================
   17. RESPONSIVE MEDIA QUERIES
   ========================================================================== */

@media (max-width: 480px) {
  .btn {
    min-width: 12rem;
    padding: var(--space-sm) var(--space-lg);
    font-size: 0.875rem;
    -webkit-box-shadow:
      0 0 0 3px var(--color-bg-deep),
      0 0 0 5px var(--color-accent-orange),
      0 4px 16px rgba(249, 115, 22, 0.2);
    box-shadow: 0 4px 16px rgba(249, 115, 22, 0.12);
  }

  .menu__actions {
    gap: var(--space-md);
  }

  .menu__controls {
    gap: var(--space-md);
    margin-top: var(--space-lg);
  }

  .menu__control-icon {
    font-size: 1.25rem;
  }

  .menu__control-label {
    font-size: 0.5625rem;
  }

  .loading__start {
    min-width: 10rem;
    padding: var(--space-sm) var(--space-lg);
    font-size: 0.875rem;
  }

  .game-header__title {
    font-size: 1rem;
  }

  .hud {
    padding: var(--space-sm) var(--space-md);
    -ms-flex-wrap: wrap;
    flex-wrap: wrap;
    gap: var(--space-sm);
  }

  /* Row 1: Menu - Title - Audio */
  .hud__left {
    -webkit-box-ordinal-group: 1;
    -ms-flex-order: 0;
    order: 0;
    -webkit-box-flex: 1;
    -ms-flex: 1;
    flex: 1;
    justify-content: flex-start;
  }

  .hud__title {
    display: block;
    font-size: 1rem;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    margin-left: var(--space-sm);
  }

  .hud__audio-btn {
    position: absolute;
    top: var(--space-sm);
    right: var(--space-md);
  }

  /* Row 2: Stats */
  .hud__info {
    -webkit-box-ordinal-group: 3;
    -ms-flex-order: 2;
    order: 2;
    width: 100%;
    -webkit-box-pack: justify;
    -ms-flex-pack: justify;
    justify-content: space-between;
    margin-top: var(--space-xs);
    /* Ensure audio button doesn't take space in flex layout */
  }

  .hud__menu-btn {
    font-size: 0.6875rem;
    padding: 0.3125rem 0.625rem;
  }

  .hud__passcode {
    display: block !important; /* Force visible on mobile */
  }

  .hud__passcode,
  .hud__stage,
  .hud__moves {
    font-size: 0.75rem;
    padding: 0.25rem 0.5rem;
    flex: 1;
    text-align: center;
    white-space: nowrap;
    padding: 0.3125rem 0.5rem;
    text-transform: uppercase;
  }

  /* Pause Menu Mobile Fixes */
  .pause-menu__content {
    width: 95%; /* Use more width on mobile */
    padding: var(--space-md);
  }

  .pause-menu__title {
    margin-bottom: var(--space-xl); /* Reduce margin */
  }

  .pause-menu__actions {
    gap: var(--space-md); /* Reduce gap */
    width: 100%;
  }

  .pause-menu__audio {
    -webkit-box-orient: horizontal;
    -ms-flex-direction: row;
    flex-direction: row; /* Side-by-side */
    gap: var(--space-sm);
    width: 100%;
    max-width: 20rem; /* Align with other buttons */
  }

  .btn {
    width: 100%; /* Make all buttons full width */
    max-width: 20rem; /* But strictly cap them */
    padding: var(--space-sm) var(--space-md); /* Reduce padding */
    min-width: unset; /* Remove min-width constraints */
  }

  .btn--audio {
    -webkit-box-flex: 1;
    -ms-flex: 1;
    flex: 1; /* Share space equally */
    width: auto;
    min-width: 0; /* Allow shrinking */
    padding: var(--space-sm) var(--space-sm);
    font-size: 0.75rem;
  }

  .hud__info {
    gap: 0.25rem;
  }

  .hud__passcode {
    display: none;
  }

  .level-select__grid {
    grid-template-columns: repeat(auto-fill, minmax(3rem, 1fr));
  }

  .dpad--visible {
    grid-template-columns: repeat(3, 3rem);
    grid-template-rows: repeat(3, 3rem);
  }
}

@media (min-width: 768px) and (orientation: landscape) {
  .dpad {
    right: var(--space-2xl);
    bottom: 50%;
    left: auto;
    -webkit-transform: translateY(50%);
    transform: translateY(50%);
  }
}

/* Fallback for browsers without backdrop-filter (RULE-COMPAT-004) */
@supports not (
  (-webkit-backdrop-filter: blur(1px)) or (backdrop-filter: blur(1px))
) {
  .game-header__btn,
  .settings__group,
  .level-select__cell,
  .hud__menu-btn,
  .hud__passcode,
  .hud__stage,
  .hud__moves,
  .hud__audio-btn,
  .dpad__btn {
    background: rgba(30, 41, 59, 0.92);
  }
}