/* =============================================
   CISO CERT TRACK — MASTER STYLESHEET
   Mobile-first. Bottom nav. Outdoor readable.
   ============================================= */

:root {
  --bg:          #0d1117;
  --bg2:         #161b22;
  --bg3:         #1c2330;
  --border:      #30363d;
  --text:        #c9d1d9;
  --text-muted:  #8b949e;
  --accent:      #58a6ff;
  --accent2:     #3fb950;
  --accent3:     #d29922;
  --accent4:     #f85149;
  --accent5:     #bc8cff;
  --cism:        #58a6ff;
  --ccsk:        #3fb950;
  --cobit:       #d29922;
  --cissp:       #bc8cff;
  --card-radius: 8px;
  --font-mono:   'SF Mono', 'Fira Code', 'Fira Mono', 'Roboto Mono', monospace;
  --font-sans:   -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --mbn-height:  64px;
}

/* =============================================
   RESET & BASE
   ============================================= */

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html { -webkit-text-size-adjust: 100%; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-sans);
  font-size: 18px;          /* outdoor-readable base on mobile */
  line-height: 1.85;        /* walking-friendly line spacing */
  min-height: 100vh;
  overflow-x: hidden;
}

/* When bottom nav is present, keep content above it */
body.has-bottom-nav {
  padding-bottom: calc(var(--mbn-height) + max(8px, env(safe-area-inset-bottom)));
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

img { max-width: 100%; height: auto; }

/* =============================================
   TOP NAV (hidden on mobile, replaced by bottom nav)
   ============================================= */

nav.top-nav,
nav:not(.mobile-bottom-nav) {
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
  padding: 0 1rem;
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  gap: 1rem;
  height: 56px;
  overflow: visible;
}

.nav-brand {
  font-weight: 700;
  font-size: 1rem;
  color: var(--text);
  white-space: nowrap;
  letter-spacing: -0.02em;
  flex-shrink: 0;
}

.nav-brand span { color: var(--accent); }

/* Hamburger — shown on mobile for secondary links */
.nav-hamburger {
  display: none;
  flex-direction: column;
  justify-content: center;
  gap: 5px;
  width: 44px;
  height: 44px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 8px;
  margin-left: auto;
}

.nav-hamburger span {
  display: block;
  height: 2px;
  background: var(--text);
  border-radius: 2px;
  transition: all 0.2s;
}

.nav-links {
  display: flex;
  gap: 0;
  list-style: none;
  overflow: visible;
  flex: 1;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}

.nav-links::-webkit-scrollbar { display: none; }

.nav-links a {
  display: block;
  padding: 0 1rem;
  height: 56px;
  line-height: 56px;
  font-size: 0.875rem;
  color: var(--text-muted);
  white-space: nowrap;
  transition: color 0.15s;
  border-bottom: 2px solid transparent;
}

.nav-links a:hover,
.nav-links a.active {
  color: var(--text);
  text-decoration: none;
  border-bottom-color: var(--accent);
}

.nav-links a.cism-link.active  { border-bottom-color: var(--cism); }
.nav-links a.ccsk-link.active  { border-bottom-color: var(--ccsk); }
.nav-links a.cobit-link.active { border-bottom-color: var(--cobit); }
.nav-links a.cissp-link.active { border-bottom-color: var(--cissp); }

/* =============================================
   NAV DROPDOWN (Cloud certs)
   ============================================= */

.nav-dropdown {
  position: relative;
}

.nav-dropdown-trigger {
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 0 1rem;
  height: 56px;
  font-size: 0.875rem;
  color: var(--text-muted);
  white-space: nowrap;
  cursor: pointer;
  background: none;
  border: none;
  border-bottom: 2px solid transparent;
  font-family: var(--font-sans);
  transition: color 0.15s;
}

.nav-dropdown-trigger:hover,
.nav-dropdown-trigger.active {
  color: var(--text);
  border-bottom-color: var(--accent);
}

.nav-dropdown-trigger svg {
  width: 12px;
  height: 12px;
  transition: transform 0.2s;
  flex-shrink: 0;
}

.nav-dropdown.open .nav-dropdown-trigger svg {
  transform: rotate(180deg);
}

.nav-dropdown-menu {
  display: none;
  position: absolute;
  top: calc(100% + 1px);
  left: 0;
  min-width: 200px;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 8px;
  box-shadow: 0 12px 32px rgba(0,0,0,0.5);
  overflow: hidden;
  z-index: 300;
  list-style: none;
  padding: 0;
  margin: 0;
}

.nav-dropdown.open .nav-dropdown-menu {
  display: block;
}

.nav-dropdown-menu a {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  padding: 0.75rem 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  border-bottom: none;
  height: auto;
  line-height: 1.4;
  transition: background 0.1s, color 0.1s;
}

.nav-dropdown-menu a:hover {
  background: var(--bg3);
  color: var(--text);
  border-bottom: none;
}

.nav-dropdown-menu a .dd-badge {
  font-size: 0.65rem;
  font-weight: 700;
  padding: 2px 6px;
  border-radius: 4px;
  letter-spacing: 0.04em;
  flex-shrink: 0;
}

/* =============================================
   MOBILE BOTTOM NAV
   ============================================= */

.mobile-bottom-nav {
  display: none;               /* hidden by default; shown at mobile breakpoint */
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: var(--mbn-height);
  background: var(--bg2);
  border-top: 1px solid var(--border);
  z-index: 300;
  align-items: stretch;
  padding-bottom: max(8px, env(safe-area-inset-bottom));
  /* backdrop blur for glass effect on iOS */
  -webkit-backdrop-filter: blur(12px);
  backdrop-filter: blur(12px);
}

.mbn-item {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 3px;
  color: var(--text-muted);
  text-decoration: none;
  min-height: 44px;           /* minimum tap target */
  padding: 6px 4px;
  transition: color 0.15s;
  position: relative;
  -webkit-tap-highlight-color: transparent;
}

.mbn-item:hover,
.mbn-item.active {
  color: var(--accent);
  text-decoration: none;
}

.mbn-item.mbn-cism.active  { color: var(--cism); }
.mbn-item.mbn-ccsk.active  { color: var(--ccsk); }
.mbn-item.mbn-cobit.active { color: var(--cobit); }
.mbn-item.mbn-cissp.active { color: var(--cissp); }

.mbn-item svg {
  width: 22px;
  height: 22px;
  flex-shrink: 0;
}

.mbn-item span {
  font-size: 10px;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  line-height: 1;
}

/* Active dot indicator */
.mbn-item.active::after {
  content: '';
  position: absolute;
  top: 4px;
  width: 4px;
  height: 4px;
  border-radius: 50%;
  background: currentColor;
}

/* =============================================
   LAYOUT
   ============================================= */

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 1.25rem 1rem;
}

.container-narrow {
  max-width: 860px;
  margin: 0 auto;
  padding: 1.25rem 1rem;
}

/* =============================================
   HERO
   ============================================= */

.hero {
  padding: 1.5rem 0 1.25rem;
  border-bottom: 1px solid var(--border);
  margin-bottom: 1.5rem;
}

.hero h1 {
  font-size: 1.6rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  margin-bottom: 0.4rem;
  line-height: 1.3;
}

.hero p {
  color: var(--text-muted);
  font-size: 0.95rem;
  line-height: 1.6;
}

/* =============================================
   CARDS
   ============================================= */

.card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--card-radius);
  padding: 1.25rem;
  transition: border-color 0.15s;
}

.card:hover        { border-color: var(--accent); }
.card.cism:hover   { border-color: var(--cism); }
.card.ccsk:hover   { border-color: var(--ccsk); }
.card.cobit:hover  { border-color: var(--cobit); }
.card.cissp:hover  { border-color: var(--cissp); }

.card h2 { font-size: 1.1rem; margin-bottom: 0.5rem; }
.card h3 { font-size: 1rem; margin-bottom: 0.5rem; }
.card p  { font-size: 0.9rem; color: var(--text-muted); }

/* =============================================
   GRID
   ============================================= */

.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: 1rem; }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: 1rem; }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1rem; }

/* =============================================
   BADGES
   ============================================= */

.badge {
  display: inline-block;
  padding: 0.2rem 0.65rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.03em;
  line-height: 1.4;
}

.badge-cism   { background: rgba(88,166,255,0.15);  color: var(--cism); }
.badge-ccsk   { background: rgba(63,185,80,0.15);   color: var(--ccsk); }
.badge-cobit  { background: rgba(210,153,34,0.15);  color: var(--cobit); }
.badge-cissp  { background: rgba(188,140,255,0.15); color: var(--cissp); }
.badge-done   { background: rgba(63,185,80,0.15);   color: var(--accent2); }
.badge-wip    { background: rgba(88,166,255,0.15);  color: var(--accent); }
.badge-review { background: rgba(210,153,34,0.15);  color: var(--accent3); }

/* =============================================
   PROGRESS BAR
   ============================================= */

.progress-bar {
  height: 6px;
  background: var(--bg3);
  border-radius: 3px;
  overflow: hidden;
  margin-top: 0.75rem;
}

.progress-fill {
  height: 100%;
  border-radius: 3px;
  transition: width 0.5s ease;
}

.progress-fill.cism  { background: var(--cism); }
.progress-fill.ccsk  { background: var(--ccsk); }
.progress-fill.cobit { background: var(--cobit); }
.progress-fill.cissp { background: var(--cissp); }

/* =============================================
   STUDY CONTENT
   ============================================= */

.study-content {
  font-size: 1.05rem;
  line-height: 1.9;
}

.study-content h2 {
  font-size: 1.3rem;
  font-weight: 700;
  margin: 2rem 0 0.85rem;
  padding-bottom: 0.4rem;
  border-bottom: 1px solid var(--border);
  color: var(--text);
  line-height: 1.3;
}

.study-content h3 {
  font-size: 1.05rem;
  font-weight: 600;
  margin: 1.5rem 0 0.6rem;
  color: var(--accent);
}

.study-content h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: 1.25rem 0 0.4rem;
  color: var(--text);
}

.study-content p {
  font-size: 1.05rem;
  line-height: 1.9;
  margin-bottom: 1rem;
}

.study-content ul,
.study-content ol {
  margin: 0.75rem 0 1rem 1.5rem;
}

.study-content li { margin-bottom: 0.5rem; }

.study-content strong { color: var(--text); }

.study-content code {
  font-family: var(--font-mono);
  font-size: 0.8em;
  background: var(--bg3);
  padding: 0.15em 0.4em;
  border-radius: 4px;
  color: var(--accent);
  word-break: break-all;
}

/* =============================================
   CALLOUTS
   ============================================= */

.callout {
  border-left: 3px solid;
  padding: 0.75rem 1rem;
  margin: 1.25rem 0;
  border-radius: 0 var(--card-radius) var(--card-radius) 0;
  background: var(--bg2);
}

.callout.tip     { border-color: var(--accent2); }
.callout.tip     .callout-title { color: var(--accent2); }
.callout.warning { border-color: var(--accent3); }
.callout.warning .callout-title { color: var(--accent3); }
.callout.danger  { border-color: var(--accent4); }
.callout.danger  .callout-title { color: var(--accent4); }
.callout.info    { border-color: var(--accent); }
.callout.info    .callout-title { color: var(--accent); }
.callout.exam    { border-color: var(--accent5); }
.callout.exam    .callout-title { color: var(--accent5); }

.callout-title {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.4rem;
}

.callout p  { margin-bottom: 0; font-size: 0.9rem; line-height: 1.7; }
.callout ul { margin: 0.5rem 0 0 1.25rem; font-size: 0.9rem; }

/* =============================================
   TABLES — scrollable wrapper on mobile
   ============================================= */

.table-scroll {
  width: 100%;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  margin: 1.25rem 0;
  /* subtle scroll shadow hints */
  background:
    linear-gradient(to right, var(--bg) 0%, transparent 30px) left,
    linear-gradient(to left,  var(--bg) 0%, transparent 30px) right;
  background-attachment: local, local;
}

table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
  min-width: 480px; /* prevents column crush */
}

th {
  background: var(--bg3);
  color: var(--text);
  font-weight: 600;
  padding: 0.75rem 1rem;
  text-align: left;
  border-bottom: 2px solid var(--border);
  white-space: nowrap;
}

td {
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
}

tr:hover td { background: var(--bg2); color: var(--text); }

/* Auto-wrap tables inside study content */
.study-content table,
.container table,
.container-narrow table {
  min-width: 0;
  display: block;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

/* =============================================
   FLASHCARDS
   ============================================= */

.flashcard-container {
  perspective: 1000px;
  width: 100%;
  max-width: 680px;
  height: 280px;          /* taller for mobile readability */
  margin: 0 auto 1.5rem;
  cursor: pointer;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
}

.flashcard {
  width: 100%;
  height: 100%;
  position: relative;
  transform-style: preserve-3d;
  transition: transform 0.55s cubic-bezier(0.4, 0, 0.2, 1);
}

.flashcard.flipped { transform: rotateY(180deg); }

.flashcard-face {
  position: absolute;
  width: 100%;
  height: 100%;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 12px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
  text-align: center;
}

.flashcard-face.back {
  transform: rotateY(180deg);
  background: var(--bg3);
  border-color: var(--accent);
}

.flashcard-label {
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.flashcard-text {
  font-size: 1.05rem;
  line-height: 1.65;
  color: var(--text);
}

.flashcard-answer {
  font-size: 0.95rem;
  line-height: 1.7;
  color: var(--text);
}

.flashcard-controls {
  display: flex;
  gap: 0.75rem;
  justify-content: center;
  align-items: center;
  margin-bottom: 1.25rem;
  flex-wrap: wrap;
}

.fc-counter {
  font-size: 0.85rem;
  color: var(--text-muted);
  min-width: 80px;
  text-align: center;
}

/* Swipe hint — only shown on touch devices */
.swipe-hint {
  display: none;
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  margin-bottom: 0.5rem;
  user-select: none;
}

/* =============================================
   QUIZ
   ============================================= */

.quiz-question {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--card-radius);
  padding: 1.25rem;
  margin-bottom: 1.25rem;
}

.quiz-question .q-number {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 0.65rem;
}

.quiz-question .q-text {
  font-size: 1rem;
  color: var(--text);
  margin-bottom: 1.1rem;
  line-height: 1.75;
}

.quiz-options {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.quiz-option {
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 14px 16px;      /* thumb-friendly padding */
  min-height: 52px;         /* large tap target */
  border: 1px solid var(--border);
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s;
  font-size: 0.95rem;
  color: var(--text-muted);
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  line-height: 1.5;
}

.quiz-option:hover {
  border-color: var(--accent);
  color: var(--text);
  background: rgba(88,166,255,0.05);
}

.quiz-option.selected  { border-color: var(--accent);  background: rgba(88,166,255,0.08);  color: var(--text); }
.quiz-option.correct   { border-color: var(--accent2); background: rgba(63,185,80,0.1);    color: var(--text); }
.quiz-option.incorrect { border-color: var(--accent4); background: rgba(248,81,73,0.1);    color: var(--text); }

.quiz-option .opt-letter {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-muted);
  min-width: 22px;
  padding-top: 0.1rem;
  flex-shrink: 0;
}

.quiz-explanation {
  margin-top: 1rem;
  padding: 0.75rem 1rem;
  background: var(--bg3);
  border-radius: 6px;
  font-size: 0.875rem;
  color: var(--text-muted);
  display: none;
  line-height: 1.7;
}

.quiz-explanation.visible { display: block; }
.quiz-explanation strong  { color: var(--accent2); }

.quiz-score {
  text-align: center;
  padding: 2rem;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--card-radius);
}

.score-number {
  font-size: 3rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  line-height: 1;
}

.score-number.pass { color: var(--accent2); }
.score-number.fail { color: var(--accent4); }

/* =============================================
   BUTTONS
   ============================================= */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.4rem;
  padding: 0.6rem 1.25rem;
  min-height: 44px;           /* minimum tap target */
  border-radius: 6px;
  border: 1px solid var(--border);
  background: var(--bg2);
  color: var(--text);
  cursor: pointer;
  font-size: 0.9rem;
  font-family: var(--font-sans);
  transition: all 0.15s;
  text-decoration: none;
  -webkit-tap-highlight-color: transparent;
  touch-action: manipulation;
  white-space: nowrap;
}

.btn:hover          { border-color: var(--accent); color: var(--accent); text-decoration: none; }
.btn-primary        { background: var(--accent); color: #000; border-color: var(--accent); font-weight: 600; }
.btn-primary:hover  { background: #79b8ff; color: #000; border-color: #79b8ff; }
.btn-sm             { padding: 0.4rem 0.9rem; font-size: 0.8rem; min-height: 36px; }

/* =============================================
   DOMAIN NAV
   ============================================= */

.domain-nav {
  display: flex;
  gap: 0.5rem;
  margin-bottom: 1.5rem;
  flex-wrap: wrap;
}

.domain-nav a {
  padding: 0.45rem 1rem;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 20px;
  font-size: 0.85rem;
  color: var(--text-muted);
  transition: all 0.15s;
  -webkit-tap-highlight-color: transparent;
}

.domain-nav a:hover,
.domain-nav a.active {
  border-color: var(--accent);
  color: var(--accent);
  text-decoration: none;
}

/* =============================================
   SESSION BOX
   ============================================= */

.session-box {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: var(--card-radius);
  padding: 1rem 1.25rem;
  margin-bottom: 1rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.session-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* =============================================
   SCHEDULE TABLE
   ============================================= */

.schedule-row {
  display: grid;
  grid-template-columns: 80px 140px 1fr auto;
  gap: 1rem;
  padding: 0.75rem 1rem;
  border-bottom: 1px solid var(--border);
  align-items: center;
  font-size: 0.875rem;
}

.schedule-row:hover { background: var(--bg2); }
.schedule-row.today { background: rgba(88,166,255,0.06); border-left: 3px solid var(--accent); }
.schedule-row.header {
  font-weight: 600;
  color: var(--text-muted);
  font-size: 0.75rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* =============================================
   KANBAN
   ============================================= */

.kanban {
  display: grid;
  grid-template-columns: 1fr; /* 1-col on mobile */
  gap: 1rem;
  align-items: start;
}

.kanban-col {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--card-radius);
  padding: 1rem;
}

.kanban-col h3 {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--border);
}

.kanban-task {
  background: var(--bg3);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.7rem 0.85rem;
  margin-bottom: 0.5rem;
  font-size: 0.85rem;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.15s;
  min-height: 44px;
  display: flex;
  align-items: center;
}

.kanban-task:hover { border-color: var(--accent); color: var(--text); }

.kanban-task.done {
  opacity: 0.55;
  text-decoration: line-through;
  text-decoration-color: var(--accent2);
}

#kanban-done-list .kanban-task.done:hover {
  opacity: 0.75;
  text-decoration: none;
  border-color: var(--accent3);
}

#kanban-done-list .kanban-task.done::after {
  content: ' ↩';
  font-size: 0.7em;
  color: var(--text-muted);
  margin-left: 0.3rem;
}

/* =============================================
   STAT CARDS — 2-col on mobile
   ============================================= */

.stat-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr); /* 2-col on mobile */
  gap: 1rem;
  margin-bottom: 1.5rem;
}

.stat-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--card-radius);
  padding: 1.25rem 1rem;
  text-align: center;
}

.stat-value {
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: -0.04em;
  color: var(--text);
  line-height: 1.1;
}

.stat-label {
  font-size: 0.7rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-top: 0.3rem;
}

/* =============================================
   SIDEBAR LAYOUT — content-first on mobile
   ============================================= */

.layout-sidebar {
  display: grid;
  grid-template-columns: 1fr; /* stack on mobile */
  gap: 1.5rem;
  align-items: start;
}

/* Sidebar appears below content on mobile */
.sidebar {
  order: 2;
}

.sidebar .card     { margin-bottom: 1rem; }

.sidebar h4 {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: 0.75rem;
}

.sidebar ul        { list-style: none; font-size: 0.9rem; }
.sidebar ul li     { margin-bottom: 0.5rem; }
.sidebar ul a      { color: var(--text-muted); }
.sidebar ul a:hover{ color: var(--text); }

/* Collapsible sidebar on mobile */
.sidebar-toggle {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  background: none;
  border: 1px solid var(--border);
  border-radius: var(--card-radius);
  padding: 0.75rem 1rem;
  color: var(--text-muted);
  font-size: 0.85rem;
  font-family: var(--font-sans);
  cursor: pointer;
  margin-bottom: 0.5rem;
  min-height: 44px;
}

.sidebar-toggle::after {
  content: '▼';
  font-size: 0.65rem;
  transition: transform 0.2s;
}

.sidebar-toggle.open::after { transform: rotate(180deg); }

.sidebar-content {
  display: none;
}

.sidebar-content.open { display: block; }

/* =============================================
   FOOTER
   ============================================= */

footer {
  margin-top: 3rem;
  padding: 1.5rem 1rem 2rem;
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.footer-powered {
  margin-top: 0.6rem;
  font-size: 0.72rem;
  color: var(--text-muted);
  opacity: 0.7;
  letter-spacing: 0.02em;
}

.footer-powered a {
  color: var(--text-muted);
  text-decoration: none;
  transition: color 0.15s;
}

.footer-powered a:hover { color: var(--accent); opacity: 1; }

/* =============================================
   HIGHLIGHT
   ============================================= */

mark {
  background: rgba(210,153,34,0.2);
  color: var(--accent3);
  padding: 0.1em 0.3em;
  border-radius: 3px;
}

/* =============================================
   SCROLLBAR
   ============================================= */

::-webkit-scrollbar         { width: 6px; height: 6px; }
::-webkit-scrollbar-track   { background: var(--bg); }
::-webkit-scrollbar-thumb   { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* =============================================
   READING MODE — topic/study pages
   ============================================= */

.reading-mode {
  max-width: 680px;
  margin-left: auto;
  margin-right: auto;
  font-size: 1.1rem;
  line-height: 1.95;
}

/* =============================================
   SCROLL HINT
   ============================================= */

.scroll-hint {
  display: block;
  text-align: center;
  font-size: 0.75rem;
  color: var(--text-muted);
  letter-spacing: 0.06em;
  padding: 0.5rem 0;
  animation: scrollBounce 1.8s ease-in-out infinite;
  user-select: none;
}

@keyframes scrollBounce {
  0%, 100% { opacity: 0.5; transform: translateY(0); }
  50%       { opacity: 1;   transform: translateY(4px); }
}

/* =============================================
   UTILITY CLASSES
   ============================================= */

/* On mobile, these flip — see media query below */
.mobile-only  { display: none; }
.desktop-only { display: block; }

.text-muted   { color: var(--text-muted); }
.text-accent  { color: var(--accent); }
.mt-1 { margin-top: 0.5rem; }
.mt-2 { margin-top: 1rem; }
.mt-3 { margin-top: 1.5rem; }
.mb-1 { margin-bottom: 0.5rem; }
.mb-2 { margin-bottom: 1rem; }
.mb-3 { margin-bottom: 1.5rem; }
.gap-wrap { display: flex; flex-wrap: wrap; gap: 0.5rem; align-items: center; }

/* =============================================
   DESKTOP OVERRIDES (≥ 769px)
   Everything above is mobile-first.
   Desktop tweaks go here.
   ============================================= */

@media (min-width: 769px) {

  /* Base typography */
  body {
    font-size: 16px;
    line-height: 1.7;
  }

  /* Top nav fully visible */
  nav:not(.mobile-bottom-nav) {
    padding: 0 2rem;
    gap: 2rem;
  }

  /* Hide mobile hamburger */
  .nav-hamburger { display: none; }

  /* Show nav links */
  .nav-links { display: flex; }

  /* Bottom nav — hidden on desktop */
  .mobile-bottom-nav { display: none !important; }

  /* Layout */
  .container         { padding: 2rem 1.5rem; }
  .container-narrow  { padding: 2rem 1.5rem; }

  /* Hero */
  .hero         { padding: 3rem 0 2rem; margin-bottom: 2rem; }
  .hero h1      { font-size: 2rem; }
  .hero p       { font-size: 1rem; }

  /* Cards */
  .card { padding: 1.5rem; }

  /* Grids */
  .grid-3 { grid-template-columns: repeat(3, 1fr); }
  .grid-4 { grid-template-columns: repeat(4, 1fr); }

  /* Study content */
  .study-content      { font-size: 1rem; line-height: 1.8; }
  .study-content h2   { font-size: 1.5rem; margin: 2.5rem 0 1rem; }
  .study-content h3   { font-size: 1.125rem; margin: 2rem 0 0.75rem; }
  .study-content p    { font-size: 1rem; line-height: 1.8; }
  .study-content code { font-size: 0.875em; word-break: normal; }

  /* Callout */
  .callout { padding: 1rem 1.25rem; margin: 1.5rem 0; }

  /* Table */
  table           { min-width: 0; display: table; overflow-x: visible; }
  .study-content table,
  .container table,
  .container-narrow table { display: table; overflow-x: visible; }

  /* Flashcard */
  .flashcard-container { height: 300px; }

  /* Kanban */
  .kanban { grid-template-columns: repeat(4, 1fr); }

  /* Stat grid */
  .stat-grid { grid-template-columns: repeat(4, 1fr); }

  /* Sidebar layout */
  .layout-sidebar { grid-template-columns: 1fr 280px; gap: 2rem; }
  .sidebar { order: 0; position: sticky; top: 70px; }
  .sidebar-toggle  { display: none; }
  .sidebar-content { display: block !important; }

  /* Schedule */
  .schedule-row { grid-template-columns: 80px 140px 1fr auto; }

  /* Utility */
  .mobile-only  { display: none; }
  .desktop-only { display: block; }

  /* Reading mode */
  .reading-mode { font-size: 1rem; line-height: 1.85; }

  /* Swipe hint — hidden on non-touch desktop */
  .swipe-hint { display: none; }

  /* Footer */
  footer { margin-top: 4rem; padding: 2rem; }
}

/* =============================================
   TABLET (769px – 1024px) fine-tune
   ============================================= */

@media (min-width: 769px) and (max-width: 1024px) {
  .kanban      { grid-template-columns: repeat(2, 1fr); }
  .stat-grid   { grid-template-columns: repeat(2, 1fr); }
  .grid-4      { grid-template-columns: repeat(2, 1fr); }
  .layout-sidebar { grid-template-columns: 1fr 240px; }
}

/* =============================================
   MOBILE (≤ 768px) — enforce mobile rules
   These catch any desktop-inherited values.
   ============================================= */

@media (max-width: 768px) {

  /* Show bottom nav */
  .mobile-bottom-nav { display: flex; }

  /* Hide desktop nav links, show hamburger */
  .nav-links      { display: none; }
  .nav-hamburger  { display: flex; }

  /* Nav bar slim on mobile */
  nav:not(.mobile-bottom-nav) {
    height: 52px;
    padding: 0 1rem;
    gap: 0.75rem;
  }

  /* Grids collapse to 1 col */
  .grid-2,
  .grid-3,
  .grid-4 { grid-template-columns: 1fr; }

  /* Kanban — 1 col */
  .kanban { grid-template-columns: 1fr; }

  /* Stat grid — 2 col */
  .stat-grid { grid-template-columns: repeat(2, 1fr); }

  /* Flashcard full width, 280px tall */
  .flashcard-container {
    max-width: 100%;
    height: 280px;
  }

  /* Show swipe hint on touch mobile */
  .swipe-hint { display: block; }

  /* Schedule — simpler stacked layout */
  .schedule-row {
    grid-template-columns: 70px 1fr;
    grid-template-rows: auto auto;
    gap: 0.25rem 0.75rem;
    padding: 0.85rem 1rem;
  }

  /* Sidebar — content first, sidebar below */
  .layout-sidebar {
    grid-template-columns: 1fr;
    gap: 1rem;
  }

  .sidebar { order: 2; }

  /* Utility flip */
  .mobile-only  { display: block; }
  .desktop-only { display: none; }

  /* Body padding for bottom nav */
  body { padding-bottom: calc(var(--mbn-height) + max(8px, env(safe-area-inset-bottom))); }

  /* No body padding if page explicitly opts out */
  body.no-bottom-nav { padding-bottom: 0; }
}

/* =============================================
   TOUCH DEVICE HELPERS (pointer: coarse)
   ============================================= */

@media (pointer: coarse) {
  /* Swipe hint visible on any touch device, even tablet */
  .swipe-hint { display: block; }

  /* Bigger tap targets */
  .btn     { min-height: 48px; }
  .btn-sm  { min-height: 40px; }

  .domain-nav a { min-height: 48px; }

  /* Remove hover states that don't work on touch */
  .card:hover        { border-color: var(--border); }
  .kanban-task:hover { border-color: var(--border); color: var(--text-muted); }
}

/* =============================================
   PRINT — strip chrome for saving to PDF
   ============================================= */

@media print {
  nav,
  .mobile-bottom-nav,
  .sidebar-toggle,
  .flashcard-controls,
  .scroll-hint,
  .swipe-hint { display: none !important; }

  body {
    background: #fff;
    color: #111;
    font-size: 11pt;
    padding-bottom: 0 !important;
  }

  .container,
  .container-narrow { max-width: 100%; padding: 0; }
}