/* ================================================================
   assets/css/dsa-roadmap.css
   DSA Mastery Roadmap — teal-green theme
   Loaded via  custom_css: dsa-roadmap  in front matter
   ================================================================ */

:root {
  --dsa-1: #00c9a7;
  --dsa-2: #00b4d8;
  --dsa-grad: linear-gradient(135deg, var(--dsa-1), var(--dsa-2));
}

/* ── Hero ─────────────────────────────────────────────────────── */
.dsa-hero {
  background: linear-gradient(135deg, #0a1f1c 0%, #0d2d2a 50%, #0a1a2e 100%);
  color: white;
  padding: 3rem 2rem 2.5rem;
  border-radius: 16px;
  margin-bottom: 1.5rem;
  text-align: center;
  position: relative;
  overflow: hidden;
}
.dsa-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse at 70% 20%, rgba(0,201,167,0.18) 0%, transparent 55%),
    radial-gradient(ellipse at 15% 80%, rgba(0,180,216,0.13) 0%, transparent 50%);
  pointer-events: none;
}
.dsa-hero h1 {
  font-size: 2.4rem;
  font-weight: 800;
  margin: 0 0 0.5rem;
  background: var(--dsa-grad);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  line-height: 1.2;
}
.dsa-hero p {
  color: rgba(255,255,255,0.68);
  font-size: 1rem;
  max-width: 580px;
  margin: 0 auto;
  line-height: 1.7;
}
.dsa-hero-stats {
  display: flex;
  justify-content: center;
  gap: 2.2rem;
  margin-top: 1.5rem;
  flex-wrap: wrap;
}
.dsa-stat-val { font-size: 1.6rem; font-weight: 800; color: var(--dsa-1); display: block; }
.dsa-stat-lbl { font-size: 0.75rem; color: rgba(255,255,255,0.5); text-transform: uppercase; letter-spacing: 0.05em; }

/* Breadcrumb */
.dsa-breadcrumb {
  display: flex; align-items: center; gap: 0.5rem;
  font-size: 0.85rem; color: var(--light-text); margin-bottom: 1.25rem;
}
.dsa-breadcrumb a { color: var(--dsa-1); text-decoration: none; }
.dsa-breadcrumb a:hover { text-decoration: underline; }
.dsa-breadcrumb span { opacity: 0.5; }

/* ── Global progress bar ──────────────────────────────────────── */
.dsa-overall-progress {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  padding: 0.9rem 1.25rem;
  margin-bottom: 1.5rem;
  display: flex; align-items: center; gap: 0.75rem; flex-wrap: wrap;
}
.dsa-op-label { font-size: 0.85rem; font-weight: 700; color: var(--text-color); white-space: nowrap; }
.dsa-op-bar-wrap { flex: 1; min-width: 120px; background: var(--border-color); border-radius: 99px; height: 6px; }
.dsa-op-bar { height: 6px; border-radius: 99px; background: var(--dsa-grad); width: 0%; transition: width 0.5s ease; }
.dsa-op-pct { font-size: 0.85rem; font-weight: 700; color: var(--dsa-1); min-width: 36px; text-align: right; }
.dsa-op-count { font-size: 0.78rem; color: var(--light-text); }

/* ── Difficulty filter ────────────────────────────────────────── */
.dsa-filter-bar {
  display: flex; align-items: center; gap: 0.5rem;
  margin-bottom: 1.25rem; flex-wrap: wrap;
}
.dsa-filter-bar label { font-size: 0.82rem; font-weight: 700; color: var(--light-text); margin-right: 0.25rem; }
.diff-btn {
  padding: 0.3rem 0.9rem;
  border-radius: 20px;
  font-size: 0.78rem;
  font-weight: 700;
  border: 1.5px solid var(--border-color);
  background: var(--card-bg);
  color: var(--light-text);
  cursor: pointer;
  transition: all 0.15s;
}
.diff-btn:hover { border-color: var(--dsa-1); }
.diff-btn.active-all, .diff-btn[data-diff="all"].active { background: var(--dsa-grad); color: #fff; border-color: transparent; }
.diff-btn[data-diff="easy"].active { background: rgba(16,185,129,0.15); color: #10b981; border-color: #10b981; }
.diff-btn[data-diff="medium"].active { background: rgba(245,158,11,0.15); color: #f59e0b; border-color: #f59e0b; }
.diff-btn[data-diff="hard"].active { background: rgba(239,68,68,0.15); color: #ef4444; border-color: #ef4444; }

/* ── Sticky chapter pill nav ──────────────────────────────────── */
.dsa-chapter-nav {
  position: sticky;
  top: 64px; /* below main navbar */
  z-index: 90;
  background: var(--bg-color);
  border-bottom: 1px solid var(--border-color);
  padding: 0.6rem 0;
  margin: 0 -1rem 1.5rem;
  padding-left: 1rem;
  padding-right: 1rem;
}
.dsa-chapter-pills {
  display: flex;
  gap: 0.4rem;
  overflow-x: auto;
  scrollbar-width: none;
  -webkit-overflow-scrolling: touch;
}
.dsa-chapter-pills::-webkit-scrollbar { display: none; }
.ch-pill {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.3rem 0.75rem;
  border-radius: 20px;
  font-size: 0.75rem;
  font-weight: 700;
  white-space: nowrap;
  text-decoration: none;
  background: var(--card-bg);
  border: 1.5px solid var(--border-color);
  color: var(--light-text);
  transition: all 0.15s;
  flex-shrink: 0;
}
.ch-pill:hover, .ch-pill.active {
  background: rgba(0,201,167,0.12);
  border-color: var(--dsa-1);
  color: var(--dsa-1);
}
.ch-pill .pill-count {
  font-size: 0.68rem;
  background: var(--bg-color);
  border-radius: 10px;
  padding: 0.05rem 0.35rem;
  color: var(--light-text);
}
.ch-pill.active .pill-count { background: rgba(0,201,167,0.2); color: var(--dsa-1); }

/* ── Chapter cards ─────────────────────────────────────────────  */
.dsa-chapters { display: flex; flex-direction: column; gap: 1.25rem; }

.ch-card {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  overflow: hidden;
  position: relative;
  transition: border-color 0.2s;
}
.ch-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 3px;
  background: var(--ch-accent, var(--dsa-grad));
}

/* Chapter card header (clickable) */
.ch-header {
  display: flex;
  align-items: center;
  gap: 0.9rem;
  padding: 1rem 1.25rem;
  cursor: pointer;
  user-select: none;
  transition: background 0.12s;
}
.ch-header:hover { background: var(--bg-color); }
.ch-num {
  width: 2.4rem; height: 2.4rem;
  border-radius: 8px;
  background: var(--ch-accent, var(--dsa-grad));
  color: #fff;
  font-weight: 900;
  font-size: 0.78rem;
  display: flex; align-items: center; justify-content: center;
  flex-shrink: 0;
  letter-spacing: -0.02em;
}
.ch-title-wrap { flex: 1; }
.ch-title { font-size: 1.05rem; font-weight: 800; color: var(--text-color); margin: 0 0 0.25rem; }
.ch-meta { display: flex; gap: 0.35rem; flex-wrap: wrap; align-items: center; }
.ch-badge {
  padding: 0.12rem 0.45rem;
  border-radius: 10px;
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.03em;
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  color: var(--light-text);
}
.ch-badge.notes-live {
  background: rgba(0,201,167,0.12);
  color: var(--dsa-1);
  border-color: transparent;
  text-decoration: none;
  display: inline-flex; align-items: center; gap: 0.2rem;
}
.ch-badge.notes-live:hover { background: rgba(0,201,167,0.22); }
.ch-badge.notes-soon { background: var(--bg-color); color: var(--light-text); cursor: default; }
.ch-chevron { font-size: 1rem; color: var(--light-text); transition: transform 0.3s; flex-shrink: 0; }
.ch-card.open .ch-chevron { transform: rotate(180deg); }

/* Progress bar row */
.ch-progress-row {
  display: flex; align-items: center; gap: 0.6rem;
  padding: 0.5rem 1.25rem;
  border-top: 1px solid var(--border-color);
}
.ch-prog-bar-wrap { flex: 1; background: var(--border-color); border-radius: 99px; height: 4px; }
.ch-prog-bar { height: 4px; border-radius: 99px; background: var(--ch-accent, var(--dsa-grad)); width: 0%; transition: width 0.4s; }
.ch-prog-text { font-size: 0.72rem; color: var(--light-text); white-space: nowrap; }
.ch-prog-pct { font-size: 0.72rem; font-weight: 700; color: var(--dsa-1); min-width: 32px; text-align: right; }

/* Chapter body (collapsible) */
.ch-body { display: none; padding: 1rem 1.25rem 1.25rem; border-top: 1px solid var(--border-color); }
.ch-card.open .ch-body { display: block; }

.ch-section-label {
  font-size: 0.72rem; font-weight: 700; text-transform: uppercase;
  letter-spacing: 0.06em; color: var(--light-text); margin: 1rem 0 0.5rem;
}

/* Pattern box */
.dsa-pattern-box {
  background: rgba(0,201,167,0.05);
  border: 1px solid rgba(0,201,167,0.2);
  border-left: 3px solid var(--dsa-1);
  border-radius: 0 6px 6px 0;
  padding: 0.75rem 1rem;
  margin-bottom: 0.75rem;
}
.dsa-pattern-box ul { margin: 0; padding-left: 1.1rem; }
.dsa-pattern-box li { font-size: 0.84rem; color: var(--text-color); margin-bottom: 0.25rem; line-height: 1.5; }
.dsa-pattern-box li:last-child { margin-bottom: 0; }
.dsa-pattern-box strong { color: var(--dsa-1); }

/* Code block toggle */
.code-toggle-btn {
  display: flex;
  align-items: center;
  gap: 0.4rem;
  font-size: 0.78rem;
  font-weight: 700;
  color: var(--dsa-2);
  cursor: pointer;
  background: none;
  border: none;
  padding: 0.35rem 0;
  margin-bottom: 0.25rem;
  transition: color 0.15s;
}
.code-toggle-btn:hover { color: var(--dsa-1); }
.code-toggle-btn .caret { transition: transform 0.25s; }
.code-toggle-btn.open .caret { transform: rotate(90deg); }
.code-block-wrap { display: none; margin-bottom: 0.75rem; }
.code-block-wrap.open { display: block; }
.code-block-wrap pre { margin: 0; border-radius: 8px; background: var(--card-bg); border: 1px solid var(--border-color); }

/* Complexity badges */
.ch-complexity { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-bottom: 0.6rem; }
.cplx-badge {
  padding: 0.2rem 0.6rem;
  border-radius: 6px;
  font-size: 0.75rem;
  font-weight: 700;
  background: rgba(0,201,167,0.1);
  color: var(--dsa-1);
  border: 1px solid rgba(0,201,167,0.2);
  font-family: monospace;
}
.cplx-badge .cplx-label { font-weight: 400; color: var(--light-text); margin-right: 0.25rem; font-family: inherit; font-size: 0.7rem; }

/* Problem table */
.ch-problem-table { width: 100%; border-collapse: collapse; font-size: 0.83rem; margin-top: 0.25rem; }
.ch-problem-table th {
  text-align: left;
  padding: 0.45rem 0.6rem;
  border-bottom: 2px solid var(--border-color);
  font-size: 0.72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--light-text);
  background: var(--bg-color);
}
.ch-problem-table td { padding: 0.45rem 0.6rem; border-bottom: 1px solid var(--border-color); vertical-align: middle; }
.ch-problem-table tr:last-child td { border-bottom: none; }
.ch-problem-table tr:hover td { background: var(--bg-color); }

/* Solved checkbox cell */
.solved-cell { width: 36px; text-align: center; }
.solved-check {
  width: 16px; height: 16px;
  border-radius: 4px;
  border: 2px solid var(--border-color);
  display: inline-flex; align-items: center; justify-content: center;
  cursor: pointer; transition: background 0.12s, border-color 0.12s;
  flex-shrink: 0;
}
tr.solved .solved-check { background: var(--dsa-1); border-color: var(--dsa-1); }
tr.solved .solved-check::after { content: '✓'; color: #fff; font-size: 0.62rem; font-weight: 800; }
tr.solved td { opacity: 0.55; }
tr.solved td:first-child { opacity: 1; }
.problem-link { color: var(--text-color); text-decoration: none; }
.problem-link:hover { color: var(--dsa-1); }

/* Difficulty badges in table */
.diff-easy   { color: #10b981; font-weight: 700; font-size: 0.75rem; white-space: nowrap; }
.diff-medium { color: #f59e0b; font-weight: 700; font-size: 0.75rem; white-space: nowrap; }
.diff-hard   { color: #ef4444; font-weight: 700; font-size: 0.75rem; white-space: nowrap; }

/* Hide rows by difficulty filter */
tr.diff-hidden { display: none; }

/* Cheatsheet section */
.dsa-cheatsheet-toggle {
  background: var(--card-bg);
  border: 1px solid var(--border-color);
  border-radius: 10px;
  margin-top: 2rem;
  overflow: hidden;
}
.dsa-cheatsheet-header {
  display: flex; align-items: center; justify-content: space-between;
  padding: 0.9rem 1.25rem;
  cursor: pointer; user-select: none;
}
.dsa-cheatsheet-header:hover { background: var(--bg-color); }
.dsa-cheatsheet-header h3 { font-size: 1rem; font-weight: 700; color: var(--text-color); margin: 0; }
.dsa-cheatsheet-body { display: none; padding: 0 1.25rem 1.25rem; border-top: 1px solid var(--border-color); }
.dsa-cheatsheet-toggle.open .dsa-cheatsheet-body { display: block; }
.dsa-cheatsheet-toggle.open .ch-chevron { transform: rotate(180deg); }

.cheatsheet-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 0.75rem;
  margin-top: 1rem;
}
.cheatsheet-card {
  background: var(--bg-color);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 0.75rem;
}
.cheatsheet-card h4 { font-size: 0.85rem; font-weight: 700; color: var(--dsa-1); margin: 0 0 0.4rem; }
.cheatsheet-card table { width: 100%; border-collapse: collapse; font-size: 0.78rem; }
.cheatsheet-card td { padding: 0.2rem 0.3rem; border-bottom: 1px solid var(--border-color); color: var(--text-color); }
.cheatsheet-card tr:last-child td { border-bottom: none; }
.cheatsheet-card td:first-child { font-family: monospace; font-weight: 700; color: var(--dsa-1); width: 40%; }

/* ── Responsive ───────────────────────────────────────────────── */
@media (max-width: 640px) {
  .dsa-hero h1 { font-size: 1.8rem; }
  .ch-header { padding: 0.85rem 1rem; }
  .ch-body { padding: 0.85rem 1rem 1rem; }
  .ch-progress-row { padding: 0.4rem 1rem; }
  .dsa-chapter-nav { top: 56px; }
}