/* =====================================================
   CSS Custom Properties — change here to retheme
   ===================================================== */
:root {
  --color-bg:          #f5f7fa;
  --color-primary:     #4361ee;
  --color-primary-dark:#3451d1;
  --color-accent:      #f72585;
  --color-success:     #4caf50;
  --color-broken-bg:   #ffcccc;
  --color-broken-fg:   #e63946;
  --color-operator-bg: #4361ee;
  --color-operator-fg: #ffffff;
  --color-calc-face:   #ffffff;
  --color-display-bg:  #1a1a2e;
  --color-display-fg:  #00e676;
  --color-bar:         #ffffff;
  --color-text:        #1a1a2e;
  --color-muted:       #6c757d;
  --color-completed:   #4caf50;

  --radius-btn:   25px;
  --radius-card:  20px;
  --radius-small: 8px;

  --shadow-btn:  0 4px 14px rgba(67,97,238,0.35);
  --shadow-card: 0 8px 32px rgba(0,0,0,0.12);

  --font-base: 'GlacialIndifference', sans-serif;
  --font-mono: 'Courier New', Courier, monospace;
}

/* =====================================================
   Font face
   ===================================================== */
@font-face {
  font-family: 'GlacialIndifference';
  src: url('../assets/GlacialIndifference-Regular.otf') format('opentype');
  font-weight: 400;
}
@font-face {
  font-family: 'GlacialIndifference';
  src: url('../assets/GlacialIndifference-Bold.otf') format('opentype');
  font-weight: 700;
}

/* =====================================================
   Reset / Base
   ===================================================== */
*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  background: var(--color-bg);
  font-family: var(--font-base);
  color: var(--color-text);
  overflow: hidden;
  -webkit-tap-highlight-color: transparent;
  user-select: none;
  -webkit-user-select: none;
}

canvas {
  display: block;
  margin: 0;
}

/* =====================================================
   Screen containers
   ===================================================== */
#homeScreen     { display: block; }
#levelsScreen   { display: none;  }
#levelsScreen1  { display: none;  }
#levelsScreen2  { display: none;  }
#calculatorScreen { display: none; }
#scientificScreen { display: none; }
#tutorialScreen { display: none;  }
#warmupScreen   { display: none;  }
#challengeHubScreen    { display: none; }
#challengeLevelsScreen { display: none; }

/* =====================================================
   Shared button base (applied via JS .addClass)
   ===================================================== */
button {
  font-family: var(--font-base);
  cursor: pointer;
  transition: background-color 0.2s ease, transform 0.1s ease, box-shadow 0.2s ease;
  -webkit-transition: background-color 0.2s ease, transform 0.1s ease, box-shadow 0.2s ease;
}
button:active {
  transform: scale(0.95);
}

/* =====================================================
   Nav / action buttons
   ===================================================== */
.btn-nav {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  height: 44px !important;
  min-width: 90px !important;
  padding: 0 18px;
  background-color: var(--color-primary) !important;
  color: #fff !important;
  font-size: 1em !important;
  font-family: var(--font-base) !important;
  border: none !important;
  border-radius: var(--radius-btn) !important;
  box-shadow: var(--shadow-btn) !important;
}
.btn-nav:active {
  background-color: var(--color-primary-dark) !important;
}

/* =====================================================
   Calculator key buttons
   ===================================================== */
.calc-btn {
  width: 64px !important;
  height: 64px !important;
  font-size: 1.5em !important;
  font-family: var(--font-base) !important;
  background-color: #f0f0f0 !important;
  color: var(--color-text) !important;
  border: none !important;
  border-radius: var(--radius-small) !important;
  box-shadow: 0 3px 6px rgba(0,0,0,0.1) !important;
  text-align: center !important;
}
.calc-btn:active {
  transform: scale(0.92) !important;
  box-shadow: 0 1px 3px rgba(0,0,0,0.1) !important;
}

.calc-btn-operator {
  background-color: var(--color-operator-bg) !important;
  color: var(--color-operator-fg) !important;
  box-shadow: 0 3px 6px rgba(67,97,238,0.3) !important;
}

.calc-btn-sci {
  background-color: #7b2d8b !important;
  color: #ffffff !important;
  font-size: 1em !important;
  box-shadow: 0 3px 6px rgba(123,45,139,0.3) !important;
}
.calc-btn-sci:active {
  background-color: #5a1f68 !important;
}

.calc-btn-equals {
  background-color: var(--color-success) !important;
  color: #fff !important;
  box-shadow: 0 3px 6px rgba(76,175,80,0.35) !important;
}

.calc-btn-ce {
  background-color: #ff9800 !important;
  color: #fff !important;
  box-shadow: 0 3px 6px rgba(255,152,0,0.35) !important;
}

.calc-btn-broken {
  background-color: var(--color-broken-bg) !important;
  color: var(--color-broken-fg) !important;
  text-decoration: line-through !important;
  cursor: not-allowed !important;
  box-shadow: none !important;
  opacity: 0.8 !important;
}
.calc-btn-broken:active {
  transform: none !important;
}

/* =====================================================
   Student calculator screen — phone calculator app look
   ===================================================== */
#calculatorScreen {
  position: relative;
  background: #1c1c1e;
}

.phone-calc-wrap {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  width: 100%;
  max-width: 480px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
}

.phone-calc-topbar {
  flex: 0 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  padding: 14px 16px 6px;
}

.phone-calc-back {
  display: inline-flex !important;
  align-items: center !important;
  justify-content: center !important;
  height: 34px !important;
  min-width: 74px !important;
  padding: 0 14px !important;
  background-color: #3a3a3c !important;
  color: #ffffff !important;
  font-size: 0.85em !important;
  font-family: var(--font-base) !important;
  border: none !important;
  border-radius: 17px !important;
  box-shadow: none !important;
  flex: 0 0 auto;
}

.phone-calc-level {
  flex: 1;
  text-align: center;
  color: #8e8e93;
  font-family: var(--font-base);
  font-size: clamp(0.8em, 3vw, 1em);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}
.phone-calc-level strong {
  color: #ffffff;
}

.phone-calc-stars {
  flex: 0 0 auto;
  min-width: 74px;
  text-align: right;
  letter-spacing: 2px;
}
.phone-calc-stars .score-star {
  font-size: clamp(0.85em, 3vw, 1.2em);
}

.phone-calc-display-wrap {
  flex: 1 1 auto;
  display: flex;
  align-items: flex-end;
  justify-content: flex-end;
  padding: 0 24px 8px;
  min-height: 0;
}

.phone-calc-display {
  width: 100% !important;
  background: transparent !important;
  color: #ffffff !important;
  border: none !important;
  outline: none !important;
  text-align: right !important;
  font-family: var(--font-mono) !important;
  font-size: clamp(38px, 11vw, 76px) !important;
  padding: 0 !important;
  line-height: 1 !important;
}

.phone-calc-grid {
  flex: 0 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(10px, 3vw, 18px);
  padding: 0 16px 24px;
}

.phone-calc-btn {
  width: 100% !important;
  aspect-ratio: 1 / 1 !important;
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  border: none !important;
  border-radius: 50% !important;
  background-color: #333333 !important;
  color: #ffffff !important;
  font-family: var(--font-base) !important;
  font-size: clamp(20px, 6vw, 30px) !important;
  box-shadow: none !important;
  padding: 0 !important;
}
.phone-calc-btn-op {
  background-color: #ff9f0a !important;
  color: #ffffff !important;
}
.phone-calc-btn-fn {
  background-color: #a5a5a5 !important;
  color: #000000 !important;
}
.phone-calc-btn-broken {
  background-color: rgba(255, 69, 58, 0.18) !important;
  color: #ff453a !important;
  text-decoration: line-through !important;
  cursor: not-allowed !important;
}
.phone-calc-btn-broken:active {
  transform: none !important;
}

@media (max-width: 360px) {
  .phone-calc-btn {
    font-size: clamp(18px, 6vw, 26px) !important;
  }
}

/* =====================================================
   Level grid buttons
   ===================================================== */
.level-btn {
  width: 90px !important;
  height: 90px !important;
  font-size: 1.6em !important;
  font-family: var(--font-base) !important;
  background-color: #e0e0e0 !important;
  color: var(--color-text) !important;
  border: none !important;
  border-radius: var(--radius-small) !important;
  box-shadow: 0 3px 8px rgba(0,0,0,0.1) !important;
}
.level-btn:active {
  transform: scale(0.93) !important;
}
.level-btn-completed {
  background-color: var(--color-completed) !important;
  color: #fff !important;
  box-shadow: 0 3px 8px rgba(76,175,80,0.4) !important;
}

/* =====================================================
   Challenge Pack hub cards
   ===================================================== */
.challenge-card {
  background: #ffffff;
  border-radius: var(--radius-card);
  box-shadow: 0 4px 16px rgba(0,0,0,0.08);
  padding: 18px 20px;
  margin-bottom: 0;
  cursor: pointer;
  transition: transform 0.15s ease, box-shadow 0.15s ease;
}
.challenge-card:active {
  transform: scale(0.98);
  box-shadow: 0 2px 8px rgba(0,0,0,0.1);
}
.challenge-card-title {
  font-family: var(--font-base);
  font-weight: 700;
  font-size: 1.15em;
  color: var(--color-primary);
  margin-bottom: 6px;
}
.challenge-card-desc {
  font-family: var(--font-base);
  font-size: 0.9em;
  color: var(--color-muted);
  line-height: 1.4;
  margin-bottom: 10px;
}
.challenge-card-progress {
  font-family: var(--font-base);
  font-size: 0.85em;
  font-weight: 700;
  color: var(--color-completed);
}

/* =====================================================
   Home screen play/tutorial buttons
   ===================================================== */
.btn-hero {
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  width: 200px !important;
  height: 56px !important;
  background-color: var(--color-primary) !important;
  color: #fff !important;
  font-size: 1.2em !important;
  font-family: var(--font-base) !important;
  border: none !important;
  border-radius: var(--radius-btn) !important;
  box-shadow: var(--shadow-btn) !important;
  letter-spacing: 0.03em !important;
}
.btn-hero:active {
  background-color: var(--color-primary-dark) !important;
  box-shadow: 0 2px 6px rgba(67,97,238,0.25) !important;
}

/* =====================================================
   Congrats overlay
   ===================================================== */
#congratsOverlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(26,26,46,0.75);
  z-index: 9999;
  align-items: center;
  justify-content: center;
}
#congratsOverlay.active {
  display: flex;
}
#congratsCard {
  background: #fff;
  border-radius: var(--radius-card);
  padding: 40px 32px;
  text-align: center;
  box-shadow: var(--shadow-card);
  max-width: 320px;
  width: 88%;
  animation: popIn 0.35s cubic-bezier(0.34,1.56,0.64,1) both;
}
#congratsCard h2 {
  font-family: var(--font-base);
  font-size: 2em;
  color: var(--color-primary);
  margin: 0 0 8px;
}
#congratsCard p {
  font-family: var(--font-base);
  font-size: 1.1em;
  color: var(--color-muted);
  margin: 0 0 28px;
}
#congratsCard .stars {
  font-size: 2.2em;
  letter-spacing: 6px;
  margin-bottom: 20px;
}
#congratsContinue {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 14px 36px;
  background: var(--color-primary);
  color: #fff;
  font-family: var(--font-base);
  font-size: 1.1em;
  border: none;
  border-radius: var(--radius-btn);
  box-shadow: var(--shadow-btn);
  cursor: pointer;
  transition: background-color 0.2s, transform 0.1s;
}
#congratsContinue:active {
  background: var(--color-primary-dark);
  transform: scale(0.95);
}

/* =====================================================
   Animations
   ===================================================== */
@keyframes popIn {
  from { opacity: 0; transform: scale(0.7); }
  to   { opacity: 1; transform: scale(1);   }
}

@keyframes starPop {
  0%   { transform: scale(1);   }
  50%  { transform: scale(1.5); }
  100% { transform: scale(1);   }
}

@keyframes shake {
  0%, 100% { transform: translateX(0);    }
  20%       { transform: translateX(-8px); }
  40%       { transform: translateX(8px);  }
  60%       { transform: translateX(-6px); }
  80%       { transform: translateX(6px);  }
}

.shake {
  animation: shake 0.4s ease both;
}

/* =====================================================
   Score stars
   ===================================================== */
.score-star {
  display: inline-block;
  font-size: 1.8em;
  color: #ccc;
  transition: color 0.3s ease;
}
.score-star.earned {
  color: var(--color-accent);
  animation: starPop 0.4s ease both;
}

/* =====================================================
   Tutorial step cards
   ===================================================== */
.tutorial-screen-inner {
  padding: 60px 20px 20px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.tutorial-step {
  background: #fff;
  border-radius: var(--radius-card);
  padding: 20px;
  box-shadow: 0 4px 16px rgba(0,0,0,0.08);
  display: flex;
  align-items: flex-start;
  gap: 16px;
}
.tutorial-step-icon {
  font-size: 2em;
  flex-shrink: 0;
}
.tutorial-step-text h3 {
  font-family: var(--font-base);
  font-size: 1em;
  font-weight: 700;
  color: var(--color-primary);
  margin: 0 0 6px;
}
.tutorial-step-text p {
  font-family: var(--font-base);
  font-size: 0.95em;
  color: var(--color-muted);
  margin: 0;
  line-height: 1.5;
}

/* =====================================================
   Progress bar on level screens
   ===================================================== */
.progress-bar-wrap {
  width: 100%;
  background: #e0e0e0;
  border-radius: 10px;
  height: 10px;
  overflow: hidden;
  margin-top: 6px;
}
.progress-bar-fill {
  height: 10px;
  background: var(--color-primary);
  border-radius: 10px;
  transition: width 0.4s ease;
}

/* =====================================================
   Scientific calculator — compact button override
   (5-column grid needs 54×46 px to fit without overlap)
   ===================================================== */
#scientificScreen .calc-btn {
  width:  54px !important;
  height: 46px !important;
  font-size: 1.1em !important;
}
#scientificScreen .calc-btn-sci {
  font-size: 0.9em !important;
}

/* =====================================================
   Teacher warm-up screen — big-screen / projector layout
   ===================================================== */
#warmupScreen {
  position: relative;
  overflow: hidden;
}

.warmup-header {
  position: absolute;
  top: 0;
  left: 0;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  background: var(--color-bar);
  box-shadow: 0 2px 8px rgba(0,0,0,0.10);
  z-index: 10;
}
.warmup-title {
  font-family: var(--font-base);
  font-weight: 700;
  font-size: clamp(1.1em, 2.2vw, 1.6em);
  color: var(--color-primary);
}

.warmup-main {
  position: absolute;
  left: 0;
  display: flex;
  flex-direction: row;
  align-items: stretch;
  gap: 24px;
  padding: 24px;
  overflow: auto;
}

.warmup-panel-left,
.warmup-panel-right {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 18px;
}
.warmup-panel-left {
  flex: 0 0 36%;
  justify-content: center;
}
.warmup-panel-right {
  flex: 1;
  justify-content: flex-start;
}

.warmup-panel-label {
  font-family: var(--font-base);
  font-weight: 700;
  font-size: clamp(1.2em, 2.6vw, 1.9em);
  color: var(--color-text);
}

.warmup-select-row {
  display: flex;
  flex-direction: row;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
  justify-content: center;
}
.warmup-select-caption {
  font-family: var(--font-base);
  font-size: clamp(0.9em, 1.4vw, 1.1em);
  color: var(--color-muted);
  margin-right: 4px;
}
.warmup-select-btn {
  width: clamp(40px, 4.5vw, 56px) !important;
  height: clamp(40px, 4.5vw, 56px) !important;
  font-size: clamp(1em, 1.8vw, 1.3em) !important;
  font-family: var(--font-base) !important;
  background-color: #e0e0e0 !important;
  color: var(--color-text) !important;
  border: none !important;
  border-radius: 50% !important;
  box-shadow: 0 3px 6px rgba(0,0,0,0.1) !important;
}
.warmup-select-btn.selected {
  background-color: var(--color-primary) !important;
  color: #fff !important;
  box-shadow: var(--shadow-btn) !important;
}

.warmup-target-display {
  font-family: var(--font-base);
  font-weight: 700;
  font-size: clamp(70px, 12vw, 220px);
  line-height: 1;
  color: var(--color-text);
  background: var(--color-calc-face);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  padding: 0.15em 0.5em;
  min-width: 2.2em;
  text-align: center;
}

.warmup-action-btn {
  display: flex !important;
  align-items: center !important;
  justify-content: center !important;
  height: clamp(48px, 6vh, 64px) !important;
  padding: 0 clamp(18px, 2.4vw, 30px) !important;
  background-color: var(--color-primary) !important;
  color: #fff !important;
  font-size: clamp(1em, 1.8vw, 1.3em) !important;
  font-family: var(--font-base) !important;
  border: none !important;
  border-radius: var(--radius-btn) !important;
  box-shadow: var(--shadow-btn) !important;
  letter-spacing: 0.02em !important;
}
.warmup-action-btn:active {
  background-color: var(--color-primary-dark) !important;
}
.warmup-action-btn-small {
  height: clamp(40px, 5vh, 52px) !important;
  font-size: clamp(0.85em, 1.4vw, 1.05em) !important;
}
.warmup-action-btn-secondary {
  background-color: #6c757d !important;
  box-shadow: 0 4px 14px rgba(108,117,125,0.35) !important;
}
.warmup-action-btn-secondary:active {
  background-color: #565e64 !important;
}
.warmup-action-btn-active {
  background-color: var(--color-accent) !important;
  box-shadow: 0 4px 14px rgba(247,37,133,0.4) !important;
}

.warmup-calc-card {
  background: var(--color-calc-face);
  border-radius: var(--radius-card);
  box-shadow: var(--shadow-card);
  padding: clamp(16px, 2vw, 28px);
  display: flex;
  flex-direction: column;
  align-items: stretch;
  gap: 14px;
}

.warmup-calc-display {
  width: 100% !important;
  height: clamp(56px, 8vh, 90px) !important;
  background: var(--color-display-bg) !important;
  color: var(--color-display-fg) !important;
  font-size: clamp(1.6em, 3.2vw, 2.6em) !important;
  font-family: var(--font-mono) !important;
  text-align: right !important;
  padding: 0 20px !important;
  border: none !important;
  border-radius: 12px !important;
  outline: none !important;
  box-sizing: border-box !important;
}
.warmup-calc-display.warmup-correct {
  box-shadow: 0 0 0 4px var(--color-success), 0 0 24px rgba(76,175,80,0.7) !important;
}

.warmup-calc-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: clamp(8px, 1.2vw, 16px);
}
#warmupScreen .warmup-calc-grid .calc-btn {
  width: 100% !important;
  height: clamp(56px, 9vh, 96px) !important;
  font-size: clamp(1.3em, 2.6vw, 2em) !important;
  position: static !important;
}

.warmup-break-controls {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  margin-top: 6px;
}
.warmup-break-btn-row {
  display: flex;
  flex-direction: row;
  gap: 12px;
  flex-wrap: wrap;
  justify-content: center;
}
.warmup-instruction {
  font-family: var(--font-base);
  font-size: clamp(0.9em, 1.4vw, 1.1em);
  color: var(--color-accent);
  text-align: center;
}

@media (max-width: 700px) {
  .warmup-main {
    flex-direction: column;
    overflow-y: auto;
  }
  .warmup-panel-left,
  .warmup-panel-right {
    flex: none;
    width: 100%;
  }
}

/* =====================================================
   Small screen adjustments
   ===================================================== */
@media (max-width: 360px) {
  .level-btn {
    width: 75px !important;
    height: 75px !important;
    font-size: 1.3em !important;
  }
  .calc-btn {
    width: 54px !important;
    height: 54px !important;
    font-size: 1.2em !important;
  }
  .btn-hero {
    width: 170px !important;
    height: 50px !important;
    font-size: 1.05em !important;
  }
}