/* ====================================================================
   1. SISTEM WARNA KOGNITIF & VARIABEL CSS (DEEP OBSIDIAN & NORDIC NEON)
   ==================================================================== */
:root {
  --bg-main: #0B1120;
  --bg-panel: #1E293B;
  --bg-panel-elevated: #263449;
  --bg-glass: rgba(30, 41, 59, 0.85);
  --border-subtle: #334155;
  --border-focus: #475569;
  --text-main: #F8FAFC;
  --text-secondary: #94A3B8;
  --text-muted: #64748B;

  /* Warna Semantik Kognitif */
  --c-blue: #38BDF8;     /* Data Populasi, Parameter Sejati (μ, σ, β, θ), Prior, Variabel X */
  --c-blue-dim: rgba(56, 189, 248, 0.16);
  --c-purple: #C084FC;   /* Data Sampel, Statistik Estimasi (x̄, s, b, θ̂), Posterior, Variabel Y */
  --c-purple-dim: rgba(192, 132, 252, 0.16);
  --c-green: #34D399;    /* Area Penerimaan H0, Confidence Interval Valid, Homoskedastisitas, Konvergensi */
  --c-green-dim: rgba(52, 211, 153, 0.16);
  --c-red: #FB7185;      /* Area Penolakan / α, Outlier Ekstrem, Residual (ε), Pelanggaran Asumsi */
  --c-red-dim: rgba(251, 113, 133, 0.16);
  --c-amber: #FBBF24;    /* Titik Keseimbangan (Mean/E[X]), Derajat Kebebasan (df), Peringatan Diagnostik */
  --c-amber-dim: rgba(251, 191, 36, 0.16);

  /* Tipografi & Ukuran */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'Cascadia Code', Consolas, monospace;
  --font-math: 'Cambria Math', 'Latin Modern Math', Georgia, serif;

  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.45), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
  --transition-fast: 160ms cubic-bezier(0.4, 0, 0.2, 1);
  --nav-bottom-h: 68px;
}

/* ====================================================================
   2. RESET & BASE MOBILE-FIRST ARCHITECTURE (320px - 640px Base)
   ==================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  background-color: var(--bg-main);
  color: var(--text-main);
  font-family: var(--font-sans);
  line-height: 1.6;
}

body {
  min-height: 100vh;
  overflow-x: hidden;
  background-color: var(--bg-main);
  background-image: 
    radial-gradient(circle at 10% 15%, rgba(56, 189, 248, 0.06) 0%, transparent 35%),
    radial-gradient(circle at 90% 80%, rgba(192, 132, 252, 0.06) 0%, transparent 35%);
  padding-bottom: calc(var(--nav-bottom-h) + 24px);
}

img, svg, canvas, video {
  max-width: 100%;
  display: block;
  box-sizing: border-box;
}

/* Tipografi Responsif dengan clamp() */
h1 { font-size: clamp(1.45rem, 3.2vw, 2.25rem); font-weight: 800; letter-spacing: -0.025em; line-height: 1.25; }
h2 { font-size: clamp(1.2rem, 2.4vw, 1.65rem); font-weight: 700; letter-spacing: -0.015em; line-height: 1.3; }
h3 { font-size: clamp(1.02rem, 1.8vw, 1.25rem); font-weight: 600; line-height: 1.35; }
p, li { font-size: clamp(0.88rem, 1.4vw, 1.02rem); color: var(--text-secondary); }
small { font-size: clamp(0.75rem, 1.1vw, 0.85rem); }

/* Standar Ukuran Sentuh Minimum 44x44px untuk Aksesibilitas Mobile */
button, .btn, select, input[type="range"], .interactive-chip, .symbol-token, .nav-item {
  min-height: 44px;
  min-width: 44px;
  touch-action: manipulation;
}

button, .btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  background: var(--bg-panel-elevated);
  color: var(--text-main);
  font-family: var(--font-sans);
  font-size: clamp(0.82rem, 1.2vw, 0.92rem);
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  user-select: none;
}

button:hover, .btn:hover {
  border-color: var(--c-blue);
  background: rgba(56, 189, 248, 0.12);
  transform: translateY(-1px);
}

button:active, .btn:active {
  transform: translateY(0);
}

.btn-primary {
  background: linear-gradient(135deg, #0284C7, #2563EB);
  border-color: var(--c-blue);
  color: #fff;
}
.btn-primary:hover {
  background: linear-gradient(135deg, #0369A1, #1D4ED8);
  box-shadow: 0 0 15px rgba(56, 189, 248, 0.35);
}

.btn-purple {
  background: rgba(192, 132, 252, 0.15);
  border-color: var(--c-purple);
  color: var(--c-purple);
}
.btn-purple:hover {
  background: rgba(192, 132, 252, 0.25);
}

.btn-emerald {
  background: rgba(52, 211, 153, 0.15);
  border-color: var(--c-green);
  color: var(--c-green);
}

/* ====================================================================
   3. LAYOUT CONTAINER, FLUID GRID & SEMANTIC COLOR BADGES
   ==================================================================== */
.app-container {
  width: 100%;
  max-width: 1480px;
  margin: 0 auto;
  padding: 12px;
}

.grid-fluid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 320px), 1fr));
  gap: 16px;
}

.grid-2col {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.card {
  background: var(--bg-panel);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 16px;
  box-shadow: var(--shadow-card);
  position: relative;
  overflow: hidden;
}

.section-header {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 16px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-subtle);
}

.section-tag {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 4px 10px;
  border-radius: 999px;
  width: fit-content;
}

/* Sistem Badge Semantik */
.sem-blue { color: var(--c-blue); background: var(--c-blue-dim); border: 1px solid rgba(56, 189, 248, 0.35); }
.sem-purple { color: var(--c-purple); background: var(--c-purple-dim); border: 1px solid rgba(192, 132, 252, 0.35); }
.sem-green { color: var(--c-green); background: var(--c-green-dim); border: 1px solid rgba(52, 211, 153, 0.35); }
.sem-red { color: var(--c-red); background: var(--c-red-dim); border: 1px solid rgba(251, 113, 133, 0.35); }
.sem-amber { color: var(--c-amber); background: var(--c-amber-dim); border: 1px solid rgba(251, 191, 36, 0.35); }

.text-blue { color: var(--c-blue) !important; }
.text-purple { color: var(--c-purple) !important; }
.text-green { color: var(--c-green) !important; }
.text-red { color: var(--c-red) !important; }
.text-amber { color: var(--c-amber) !important; }

/* ====================================================================
   4. STICKY HEADER, NAVIGASI 6 MODUL & MOBILE BOTTOM BAR
   ==================================================================== */
.top-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--bg-glass);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-subtle);
  padding: 10px 12px;
}

.header-inner {
  max-width: 1480px;
  margin: 0 auto;
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

.brand-block {
  display: flex;
  align-items: center;
  gap: 10px;
}

.brand-logo {
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: linear-gradient(135deg, var(--c-blue), var(--c-purple));
  display: grid;
  place-items: center;
  font-weight: 900;
  font-family: var(--font-math);
  font-size: 1.35rem;
  color: #0B1120;
  box-shadow: 0 0 15px rgba(56, 189, 248, 0.4);
  flex-shrink: 0;
}

.header-actions {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
}

/* Navigasi Desktop (Tersembunyi di layar kecil, tampil di >=1024px) */
.desktop-nav {
  display: none;
  max-width: 1480px;
  margin: 8px auto 0;
  padding-top: 8px;
  border-top: 1px solid rgba(51, 65, 85, 0.6);
  gap: 6px;
  overflow-x: auto;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 12px;
  border-radius: var(--radius-sm);
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.84rem;
  font-weight: 600;
  border: 1px solid transparent;
  transition: all var(--transition-fast);
  white-space: nowrap;
}

.nav-link:hover {
  color: var(--text-main);
  background: rgba(255, 255, 255, 0.04);
  border-color: var(--border-subtle);
}

.nav-link.active {
  color: var(--c-blue);
  background: var(--c-blue-dim);
  border-color: rgba(56, 189, 248, 0.4);
}

.nav-badge {
  font-size: 0.7rem;
  padding: 1px 6px;
  border-radius: 4px;
  background: rgba(15, 23, 42, 0.7);
  color: var(--text-main);
}

/* Navigasi Bawah Khusus Mobile/Tablet (<1024px) */
.mobile-bottom-nav {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--nav-bottom-h);
  background: rgba(11, 17, 32, 0.95);
  backdrop-filter: blur(12px);
  border-top: 1px solid var(--border-subtle);
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  z-index: 120;
  padding: 4px;
}

.mobile-nav-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2px;
  text-decoration: none;
  color: var(--text-secondary);
  font-size: 0.65rem;
  font-weight: 600;
  border-radius: 8px;
  padding: 4px 2px;
  text-align: center;
  line-height: 1.1;
}

.mobile-nav-item svg {
  width: 20px;
  height: 20px;
  stroke: currentColor;
  fill: none;
  stroke-width: 2;
}

.mobile-nav-item.active {
  color: var(--c-blue);
  background: var(--c-blue-dim);
}

/* ====================================================================
   5. HERO & LEGEND WARNA KOGNITIF
   ==================================================================== */
.cognitive-legend {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 210px), 1fr));
  gap: 10px;
  margin-top: 14px;
}

.legend-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  background: rgba(15, 23, 42, 0.65);
  border: 1px solid var(--border-subtle);
}

.legend-dot {
  width: 14px;
  height: 14px;
  border-radius: 4px;
  margin-top: 4px;
  flex-shrink: 0;
}

/* ====================================================================
   6. MODUL A: FORMULA DECONSTRUCTOR & LIVE CURVE MANIPULATOR
   ==================================================================== */
.formula-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 16px;
}

.formula-tab.active {
  background: var(--c-blue-dim);
  border-color: var(--c-blue);
  color: var(--c-blue);
}

.formula-stage {
  background: #070C17;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 18px 14px;
  margin-bottom: 14px;
  text-align: center;
  overflow-x: auto;
}

.formula-expression {
  display: inline-flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 6px;
  font-family: var(--font-math);
  font-size: clamp(1.15rem, 2.5vw, 1.65rem);
  line-height: 2;
}

.symbol-token {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 4px 10px;
  border-radius: 8px;
  border: 1px solid transparent;
  cursor: pointer;
  transition: all var(--transition-fast);
  font-weight: 700;
}

.symbol-token:hover, .symbol-token.active-token {
  transform: scale(1.08);
  box-shadow: 0 0 16px currentColor;
}

.symbol-inspector {
  background: rgba(15, 23, 42, 0.8);
  border-left: 4px solid var(--c-blue);
  border-radius: var(--radius-sm);
  padding: 14px;
  margin-bottom: 16px;
}

.slider-group {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 220px), 1fr));
  gap: 12px;
  margin-top: 12px;
}

.slider-box {
  background: rgba(15, 23, 42, 0.6);
  border: 1px solid var(--border-subtle);
  padding: 10px 12px;
  border-radius: var(--radius-sm);
}

.slider-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.85rem;
  font-weight: 600;
  margin-bottom: 4px;
}

input[type="range"] {
  width: 100%;
  accent-color: var(--c-blue);
  cursor: pointer;
}

.canvas-wrapper {
  width: 100%;
  height: 330px;
  background: #070B14;
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  position: relative;
  overflow: hidden;
}

.canvas-wrapper canvas {
  width: 100%;
  height: 100%;
}

/* ====================================================================
   7. MODUL B: FORCE-DIRECTED KNOWLEDGE GRAPH (PETA KONSTELASI)
   ==================================================================== */
.graph-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 12px;
  align-items: center;
  justify-content: space-between;
}

.filter-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
}

.filter-pill.active {
  border-color: var(--c-amber);
  background: var(--c-amber-dim);
  color: var(--c-amber);
}

.graph-canvas-box {
  width: 100%;
  height: 440px;
  background: radial-gradient(circle at center, #0F172A 0%, #060A12 100%);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  position: relative;
  cursor: grab;
  touch-action: none;
}

.graph-canvas-box:active {
  cursor: grabbing;
}

.node-detail-panel {
  display: flex;
  flex-direction: column;
  gap: 12px;
  background: rgba(15, 23, 42, 0.75);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: 16px;
}

.formula-callout {
  font-family: var(--font-mono);
  background: #070C17;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  color: var(--c-amber);
  font-size: 0.9rem;
  overflow-x: auto;
}

/* ====================================================================
   8. MODUL C: 30-CELL BLOOM HEATMAP & 5-PILLAR RADAR CHART
   ==================================================================== */
.bloom-table-wrap {
  width: 100%;
  overflow-x: auto;
  padding-bottom: 6px;
}

.bloom-matrix {
  display: grid;
  grid-template-columns: 115px repeat(6, minmax(56px, 1fr));
  gap: 6px;
  min-width: 520px;
}

.bloom-header-cell {
  font-size: 0.75rem;
  font-weight: 700;
  text-align: center;
  padding: 8px 4px;
  background: rgba(15, 23, 42, 0.8);
  border-radius: 6px;
  color: var(--text-secondary);
  border: 1px solid var(--border-subtle);
}

.bloom-row-label {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 6px 10px;
  background: rgba(15, 23, 42, 0.8);
  border-radius: 6px;
  font-size: 0.8rem;
  font-weight: 700;
  border: 1px solid var(--border-subtle);
}

.bloom-cell {
  min-height: 48px;
  border-radius: 8px;
  border: 1px solid var(--border-subtle);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  font-size: 0.82rem;
  font-weight: 700;
  cursor: pointer;
  transition: transform 0.15s ease, border-color 0.15s ease;
}

.bloom-cell:hover, .bloom-cell.selected-cell {
  transform: scale(1.06);
  border-color: #fff;
  box-shadow: 0 0 12px rgba(56, 189, 248, 0.5);
  z-index: 2;
}

/* ====================================================================
   9. MODUL D: VISUAL SPACED REPETITION (SRS) FLASHCARDS
   ==================================================================== */
.srs-deck-container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
}

.srs-card-stage {
  background: linear-gradient(160deg, #162033 0%, #0F172A 100%);
  border: 1px solid var(--border-focus);
  border-radius: var(--radius-lg);
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.srs-mini-canvas-wrap {
  width: 100%;
  height: 200px;
  background: #070B14;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border-subtle);
  overflow: hidden;
}

.srs-answer-box {
  background: rgba(11, 17, 32, 0.85);
  border: 1px dashed var(--c-purple);
  border-radius: var(--radius-sm);
  padding: 14px;
  display: none;
}

.srs-answer-box.revealed {
  display: block;
  animation: fadeIn 0.25s ease-out;
}

.sm2-buttons {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 8px;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(4px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ====================================================================
   10. MODUL E: GREEK ALPHABET & STATISTICAL NOTATION EXPLORER
   ==================================================================== */
.notation-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 76px), 1fr));
  gap: 8px;
  margin-bottom: 16px;
}

.notation-tile {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 10px 6px;
  border-radius: var(--radius-sm);
  background: rgba(15, 23, 42, 0.7);
  border: 1px solid var(--border-subtle);
  cursor: pointer;
  transition: all var(--transition-fast);
}

.notation-tile .sym {
  font-family: var(--font-math);
  font-size: 1.4rem;
  font-weight: 700;
  color: var(--c-blue);
}

.notation-tile .name {
  font-size: 0.7rem;
  color: var(--text-secondary);
}

.notation-tile.active {
  background: var(--c-blue-dim);
  border-color: var(--c-blue);
  transform: translateY(-2px);
}

.branch-comparison-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(min(100%, 240px), 1fr));
  gap: 12px;
  margin-top: 12px;
}

.branch-card {
  background: rgba(15, 23, 42, 0.7);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-sm);
  padding: 12px;
}

/* Toast Notification */
#toastNotification {
  position: fixed;
  bottom: 84px;
  right: 16px;
  z-index: 999;
  background: #0F172A;
  border: 1px solid var(--c-green);
  color: var(--text-main);
  padding: 12px 16px;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-card);
  font-size: 0.85rem;
  font-weight: 600;
  opacity: 0;
  pointer-events: none;
  transform: translateY(10px);
  transition: all 0.25s ease;
}
#toastNotification.show {
  opacity: 1;
  transform: translateY(0);
}

/* ====================================================================
   11. PROGRESSIVE MEDIA QUERIES (TABLET, LAPTOP, ULTRA-WIDE)
   ==================================================================== */
/* Tablet (min-width: 768px) */
@media (min-width: 768px) {
  .app-container {
    padding: 20px;
  }
  .card {
    padding: 22px;
  }
  .section-header {
    flex-direction: row;
    align-items: center;
    justify-content: space-between;
  }
  .sm2-buttons {
    grid-template-columns: repeat(4, 1fr);
  }
}

/* Laptop / PC (min-width: 1024px) */
@media (min-width: 1024px) {
  body {
    padding-bottom: 40px;
  }
  .desktop-nav {
    display: flex;
  }
  .mobile-bottom-nav {
    display: none;
  }
  .grid-2col {
    grid-template-columns: 1.15fr 0.85fr;
  }
  .grid-2col-equal {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
  }
  #toastNotification {
    bottom: 24px;
  }
}

/* Monitor Lebar (min-width: 1440px) */
@media (min-width: 1440px) {
  .app-container {
    padding: 28px 32px;
  }
  .canvas-wrapper {
    height: 380px;
  }
  .graph-canvas-box {
    height: 500px;
  }
}