/* ==========================================================================
   Marketing Cloud Next — Certification Instructor
   ========================================================================== */

:root {
  /* Salesforce brand palette, dark theme */
  --bg: #0a1a2f;
  --bg-elev: #10233c;
  --bg-elev-2: #162c4a;
  --bg-hover: #1d3657;
  --border: #24405f;
  --border-soft: #1b3350;
  --text: #eef4fb;
  --text-dim: #a8bcd4;
  --text-faint: #7d93ad;
  --accent: #1b96ff;          /* Cloud Blue */
  --accent-soft: rgba(27, 150, 255, 0.16);
  --accent-2: #04b4c4;        /* Teal */
  --good: #2e844a;            /* Salesforce Green */
  --good-soft: rgba(46, 132, 74, 0.18);
  --bad: #ea001e;             /* Salesforce Red */
  --bad-soft: rgba(234, 0, 30, 0.16);
  --warn: #fcc003;            /* Salesforce Yellow */
  --warn-soft: rgba(252, 192, 3, 0.16);
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 12px 40px rgba(0, 0, 0, 0.4);
  --shadow-sm: 0 2px 10px rgba(0, 0, 0, 0.25);
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
  --mono: ui-monospace, SFMono-Regular, "SF Mono", Menlo, Consolas, monospace;
  --sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Inter, Roboto, "Helvetica Neue", Arial, sans-serif;
  --sidebar-w: 264px;
}

[data-theme="light"] {
  /* Salesforce brand palette, light theme */
  --bg: #f3f6fb;
  --bg-elev: #ffffff;
  --bg-elev-2: #eef3fa;
  --bg-hover: #e6eef8;
  --border: #d8e2f0;
  --border-soft: #e6edf7;
  --text: #032d60;            /* Salesforce Navy */
  --text-dim: #4a5f7d;
  --text-faint: #7d93ad;
  --accent: #0176d3;          /* Salesforce Blue */
  --accent-soft: rgba(1, 118, 211, 0.1);
  --accent-2: #04b4c4;        /* Teal */
  --good: #2e844a;
  --good-soft: rgba(46, 132, 74, 0.1);
  --bad: #ea001e;
  --bad-soft: rgba(234, 0, 30, 0.08);
  --warn: #dd7a01;            /* Salesforce Orange (readable on light) */
  --warn-soft: rgba(221, 122, 1, 0.1);
  --shadow: 0 10px 30px rgba(3, 45, 96, 0.12);
  --shadow-sm: 0 1px 4px rgba(3, 45, 96, 0.08);
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

html, body { margin: 0; padding: 0; height: 100%; }

body {
  background:
    radial-gradient(1200px 600px at 85% -10%, var(--accent-soft), transparent 60%),
    radial-gradient(900px 500px at -10% 110%, rgba(4, 180, 196, 0.07), transparent 55%),
    var(--bg);
  background-attachment: fixed;
  color: var(--text);
  font-family: var(--sans);
  font-size: 15px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
}

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

/* ---------- Layout ---------- */

.app { display: grid; grid-template-columns: var(--sidebar-w) 1fr; min-height: 100vh; }

.sidebar {
  background: var(--bg-elev);
  border-right: 1px solid var(--border);
  padding: 20px 14px;
  position: sticky;
  top: 0;
  height: 100vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 4px 8px 16px;
  border-bottom: 1px solid var(--border-soft);
  margin-bottom: 12px;
}

.brand-mark {
  width: 34px; height: 34px;
  border-radius: 9px;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  display: grid; place-items: center;
  font-weight: 800; font-size: 13px; color: #fff;
  flex-shrink: 0; letter-spacing: -0.5px;
}

.brand-text { min-width: 0; }
.brand-title { font-weight: 700; font-size: 13.5px; line-height: 1.25; }
.brand-sub { font-size: 11px; color: var(--text-faint); }

.nav-group-label {
  font-size: 10.5px;
  text-transform: uppercase;
  letter-spacing: 0.09em;
  color: var(--text-faint);
  font-weight: 700;
  padding: 14px 10px 6px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  color: var(--text-dim);
  font-size: 13.5px;
  font-weight: 500;
  cursor: pointer;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  font-family: inherit;
  transition: background 0.12s, color 0.12s;
}

.nav-item:hover { background: var(--bg-hover); color: var(--text); text-decoration: none; }
.nav-item.active { background: var(--accent-soft); color: var(--accent); font-weight: 600; }
.nav-item .ico { width: 17px; text-align: center; flex-shrink: 0; font-size: 14px; }
.nav-item .count { margin-left: auto; font-size: 11px; color: var(--text-faint); font-variant-numeric: tabular-nums; }

.sidebar-footer { margin-top: auto; padding-top: 14px; border-top: 1px solid var(--border-soft); display: flex; gap: 6px; }

.main { min-width: 0; display: flex; flex-direction: column; }

.topbar {
  position: sticky;
  top: 0;
  z-index: 40;
  background: var(--bg);
  border-bottom: 1px solid var(--border);
  padding: 10px 26px;
  display: flex;
  align-items: center;
  gap: 14px;
}

.search-wrap { position: relative; flex: 1; max-width: 520px; }

.search-input {
  width: 100%;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 8px 12px 8px 34px;
  color: var(--text);
  font-size: 13.5px;
  font-family: inherit;
  outline: none;
}

.search-input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }
.search-icon { position: absolute; left: 11px; top: 50%; transform: translateY(-50%); color: var(--text-faint); font-size: 13px; }

.search-results {
  position: absolute;
  top: calc(100% + 6px);
  left: 0; right: 0;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  max-height: 420px;
  overflow-y: auto;
  z-index: 50;
  padding: 6px;
}

.search-result {
  display: block;
  padding: 8px 10px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  border: none;
  background: none;
  width: 100%;
  text-align: left;
  font-family: inherit;
  color: var(--text);
}

.search-result:hover, .search-result.active { background: var(--bg-hover); }
.search-result .sr-title { font-size: 13px; font-weight: 600; }
.search-result .sr-meta { font-size: 11px; color: var(--text-faint); margin-top: 1px; }
.search-empty { padding: 14px; text-align: center; color: var(--text-faint); font-size: 13px; }

.content { padding: 26px; max-width: 1080px; width: 100%; margin: 0 auto; flex: 1; animation: fade-in 0.4s var(--ease); }

@keyframes fade-in {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------- Buttons ---------- */

.btn {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 8px 15px;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  font-size: 13.5px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease), transform 0.15s var(--ease), box-shadow 0.2s var(--ease);
}

.btn:hover { background: var(--bg-hover); border-color: var(--accent); text-decoration: none; }
.btn:active { transform: translateY(1px); }
.btn:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
.btn-primary { background: var(--accent); border-color: var(--accent); color: #fff; box-shadow: 0 2px 10px var(--accent-soft); }
.btn-primary:hover { background: var(--accent); filter: brightness(0.9); border-color: var(--accent); }
.btn-ghost { background: transparent; border-color: transparent; color: var(--text-dim); }
.btn-ghost:hover { background: var(--bg-hover); color: var(--text); border-color: transparent; }
.btn-sm { padding: 5px 12px; font-size: 12.5px; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

.icon-btn {
  width: 34px; height: 34px;
  display: grid; place-items: center;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text-dim);
  cursor: pointer;
  font-size: 15px;
  flex-shrink: 0;
}

.icon-btn:hover { background: var(--bg-hover); color: var(--text); }

/* ---------- Typography ---------- */

h1 { font-size: 28px; font-weight: 750; letter-spacing: -0.025em; margin: 0 0 6px; line-height: 1.2; }
h2 { font-size: 19px; font-weight: 700; letter-spacing: -0.015em; margin: 30px 0 12px; }
h3 { font-size: 16px; font-weight: 650; margin: 22px 0 8px; }
h4 { font-size: 14.5px; font-weight: 650; margin: 18px 0 6px; }

.page-head { margin-bottom: 22px; }
.page-sub { color: var(--text-dim); font-size: 14px; margin: 0; }
.eyebrow { font-size: 11px; text-transform: uppercase; letter-spacing: 0.1em; font-weight: 700; color: var(--accent); margin-bottom: 6px; }

/* ---------- Cards ---------- */

.card { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 20px; box-shadow: var(--shadow-sm); }
.card-pad-sm { padding: 14px; }

.grid { display: grid; gap: 14px; }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(210px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(160px, 1fr)); }

.stat { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px 18px; box-shadow: var(--shadow-sm); transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease); }
.stat:hover { transform: translateY(-3px); box-shadow: var(--shadow); }
.stat-value { font-size: 26px; font-weight: 750; letter-spacing: -0.02em; line-height: 1.1; font-variant-numeric: tabular-nums; }
.stat-label { font-size: 11.5px; color: var(--text-faint); text-transform: uppercase; letter-spacing: 0.07em; font-weight: 650; margin-top: 3px; }

/* ---------- Section bars ---------- */

.section-row {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 12px 15px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease), transform 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.section-row:hover { border-color: var(--accent); background: var(--bg-hover); transform: translateY(-1px); box-shadow: var(--shadow-sm); }

.section-row-main {
  display: grid;
  grid-template-columns: 30px 1fr auto;
  align-items: center;
  gap: 12px;
  flex: 1;
  min-width: 0;
  color: inherit;
}

.section-row-main:hover { text-decoration: none; }

.section-quiz-btn { flex-shrink: 0; }
.section-num { width: 26px; height: 26px; border-radius: 8px; display: grid; place-items: center; font-size: 12px; font-weight: 750; color: #fff; }
.section-name { font-size: 13.5px; font-weight: 600; }
.section-meta { font-size: 11.5px; color: var(--text-faint); }
.section-weight { font-size: 15px; font-weight: 750; font-variant-numeric: tabular-nums; }

.bar { height: 5px; background: var(--bg-elev-2); border-radius: 3px; overflow: hidden; margin-top: 6px; }
.bar-fill { height: 100%; border-radius: 3px; transition: width 0.4s ease; }

/* ---------- List items ---------- */

.list-item {
  display: block;
  padding: 13px 16px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease), transform 0.2s var(--ease), box-shadow 0.2s var(--ease);
  color: inherit;
}

.list-item:hover { border-color: var(--accent); background: var(--bg-hover); text-decoration: none; transform: translateY(-1px); box-shadow: var(--shadow-sm); }
.list-item-title { font-size: 14px; font-weight: 650; display: flex; align-items: center; gap: 8px; }
.list-item-desc { font-size: 12.5px; color: var(--text-dim); margin-top: 3px; line-height: 1.5; }

.chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 2px 8px;
  border-radius: 20px;
  font-size: 11px;
  font-weight: 650;
  background: var(--bg-elev-2);
  color: var(--text-dim);
  border: 1px solid var(--border);
  white-space: nowrap;
}

.chip-accent { background: var(--accent-soft); color: var(--accent); border-color: transparent; }
.chip-good { background: var(--good-soft); color: var(--good); border-color: transparent; }
.chip-warn { background: var(--warn-soft); color: var(--warn); border-color: transparent; }
.chip-bad { background: var(--bad-soft); color: var(--bad); border-color: transparent; }

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

/* ---------- Prose ---------- */

.prose { font-size: 14.5px; line-height: 1.72; }
.prose > *:first-child { margin-top: 0; }
.prose p { margin: 0 0 13px; }
.prose ul, .prose ol { margin: 0 0 13px; padding-left: 22px; }
.prose li { margin-bottom: 5px; }
.prose li > ul, .prose li > ol { margin-top: 5px; margin-bottom: 0; }
.prose strong { font-weight: 680; color: var(--text); }
.prose code {
  font-family: var(--mono);
  font-size: 0.87em;
  background: var(--bg-elev-2);
  padding: 1.5px 5px;
  border-radius: 5px;
  border: 1px solid var(--border-soft);
}
.prose pre {
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 13px 15px;
  overflow-x: auto;
  margin: 0 0 14px;
}
.prose pre code { background: none; border: none; padding: 0; font-size: 12.5px; line-height: 1.6; }
.prose blockquote {
  margin: 0 0 14px;
  padding: 11px 15px;
  border-left: 3px solid var(--accent);
  background: var(--accent-soft);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  color: var(--text-dim);
  font-size: 13.5px;
}
.prose blockquote p:last-child { margin-bottom: 0; }
.prose hr { border: none; border-top: 1px solid var(--border); margin: 22px 0; }
.prose h2 { font-size: 18px; margin: 26px 0 10px; }
.prose h3 { font-size: 15.5px; margin: 20px 0 8px; }
.prose h4 { font-size: 14px; margin: 16px 0 6px; }

.table-wrap { overflow-x: auto; margin: 0 0 14px; border: 1px solid var(--border); border-radius: var(--radius-sm); }
.prose table { border-collapse: collapse; width: 100%; font-size: 13px; }
.prose th, .prose td { padding: 8px 12px; text-align: left; border-bottom: 1px solid var(--border-soft); vertical-align: top; }
.prose th { background: var(--bg-elev-2); font-weight: 680; font-size: 12px; text-transform: uppercase; letter-spacing: 0.04em; color: var(--text-dim); }
.prose tbody tr:last-child td { border-bottom: none; }
.prose tbody tr:hover { background: var(--bg-elev-2); }

.wikilink { color: var(--accent); border-bottom: 1px dashed var(--accent); font-weight: 550; }
.wikilink:hover { text-decoration: none; border-bottom-style: solid; }
.wikilink--missing { color: var(--text-faint); border-bottom-color: var(--border); }

/* ---------- Callouts ---------- */

.callout { border-radius: var(--radius-sm); padding: 13px 15px; margin-bottom: 14px; font-size: 13.5px; border: 1px solid transparent; }
.callout-title { font-weight: 700; font-size: 12px; text-transform: uppercase; letter-spacing: 0.06em; margin-bottom: 6px; display: flex; align-items: center; gap: 6px; }
.callout p:last-child { margin-bottom: 0; }
.callout ul { margin-bottom: 0; }
.callout-warn { background: var(--warn-soft); border-color: var(--warn); }
.callout-warn .callout-title { color: var(--warn); }
.callout-accent { background: var(--accent-soft); border-color: var(--accent); }
.callout-accent .callout-title { color: var(--accent); }
.callout-good { background: var(--good-soft); border-color: var(--good); }
.callout-good .callout-title { color: var(--good); }
.callout-bad { background: var(--bad-soft); border-color: var(--bad); }
.callout-bad .callout-title { color: var(--bad); }

/* ---------- Concept page actions ---------- */

.concept-actions {
  display: flex;
  gap: 10px;
  align-items: center;
  flex-wrap: wrap;
  margin-top: 28px;
  padding-top: 22px;
  border-top: 1px solid var(--border-soft);
}

/* ---------- Study path (dashboard) ---------- */

.study-path {
  margin-bottom: 30px;
  padding: 26px;
  background: linear-gradient(160deg, var(--bg-elev), var(--bg-elev-2));
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

.study-path-head { margin-bottom: 20px; }
.study-path-head h2 { margin: 0 0 4px; }
.study-path-head .page-sub { font-size: 13.5px; }

.study-steps {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-direction: column;
  gap: 0;
}

.study-step {
  display: flex;
  gap: 16px;
  position: relative;
  padding: 0 0 22px;
}

.study-step:last-child { padding-bottom: 0; }

/* Vertical connector line between steps */
.study-step:not(:last-child)::before {
  content: '';
  position: absolute;
  left: 17px;
  top: 38px;
  bottom: 0;
  width: 2px;
  background: linear-gradient(var(--border), var(--border-soft));
}

.study-step-num {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  font-weight: 750;
  font-size: 15px;
  display: grid;
  place-items: center;
  flex-shrink: 0;
  box-shadow: 0 2px 10px var(--accent-soft);
  z-index: 1;
}

.study-step-body { flex: 1; min-width: 0; padding-top: 2px; }

.study-step-title { font-size: 15px; font-weight: 700; letter-spacing: -0.01em; margin-bottom: 3px; }

.study-step-desc { font-size: 13.5px; color: var(--text-dim); line-height: 1.6; margin: 0 0 12px; }

.study-step-actions { display: flex; gap: 9px; flex-wrap: wrap; }

/* ---------- Resume card (dashboard) ---------- */

.resume-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 16px 18px;
  margin-bottom: 22px;
  background: linear-gradient(135deg, var(--accent-soft), transparent 60%), var(--bg-elev);
  border: 1px solid var(--accent);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), border-color 0.25s var(--ease);
}

.resume-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); text-decoration: none; }

.resume-icon {
  width: 40px; height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  display: grid; place-items: center;
  font-size: 15px;
  flex-shrink: 0;
  box-shadow: 0 2px 10px var(--accent-soft);
}

.resume-body { flex: 1; min-width: 0; }
.resume-label { font-size: 11px; text-transform: uppercase; letter-spacing: 0.08em; font-weight: 700; color: var(--accent); margin-bottom: 2px; }
.resume-title { font-size: 15px; font-weight: 700; letter-spacing: -0.01em; color: var(--text); }
.resume-arrow { font-size: 18px; color: var(--accent); flex-shrink: 0; }

/* ---------- Instructor note ---------- */

.instructor-note {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 14px 16px;
  margin-bottom: 22px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
}

.instructor-avatar {
  width: 34px; height: 34px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  font-weight: 800; font-size: 11px;
  display: grid; place-items: center;
  flex-shrink: 0;
  letter-spacing: -0.5px;
}

.instructor-text { font-size: 14px; color: var(--text-dim); line-height: 1.6; padding-top: 5px; }

/* ---------- Section cards (dashboard) ---------- */

.section-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
  gap: 14px;
}

.section-card {
  display: flex;
  flex-direction: column;
  gap: 12px;
  padding: 16px 18px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow-sm);
  transition: transform 0.25s var(--ease), box-shadow 0.25s var(--ease), border-color 0.25s var(--ease);
}

.section-card:hover { transform: translateY(-2px); box-shadow: var(--shadow); border-color: var(--border); }

.section-card-head { display: flex; align-items: flex-start; gap: 12px; }
.section-card-title { flex: 1; min-width: 0; }
.section-blurb { font-size: 12.5px; color: var(--text-faint); margin-top: 2px; line-height: 1.45; }

.section-card-resources { display: flex; flex-wrap: wrap; gap: 7px; }

.resource-chip {
  display: inline-flex;
  align-items: center;
  gap: 5px;
  padding: 4px 10px;
  border-radius: 999px;
  font-size: 12px;
  font-weight: 600;
  background: var(--bg-elev-2);
  color: var(--text-dim);
  border: 1px solid var(--border);
  transition: border-color 0.15s var(--ease), color 0.15s var(--ease), background 0.15s var(--ease);
}

.resource-chip:hover { border-color: var(--accent); color: var(--accent); background: var(--accent-soft); text-decoration: none; }
.resource-ico { font-size: 12px; }

.section-card-actions { display: flex; gap: 8px; margin-top: auto; }

/* ---------- Inline concept quiz ---------- */

.inline-quiz-progress { margin-bottom: 14px; }
.inline-quiz-progress .bar { margin-top: 6px; }

.inline-quiz-q { margin-bottom: 14px; }

.inline-quiz-done {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 6px 0;
}

.inline-quiz-score {
  width: 52px; height: 52px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #fff;
  font-weight: 750;
  font-size: 16px;
  display: grid; place-items: center;
  flex-shrink: 0;
  box-shadow: 0 2px 10px var(--accent-soft);
}

.inline-quiz-done-text { font-size: 14px; color: var(--text-dim); }

/* ---------- Concept navigation ---------- */

.concept-nav {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
  margin-top: 26px;
  padding-top: 22px;
  border-top: 1px solid var(--border-soft);
}

.concept-nav-link {
  display: flex;
  flex-direction: column;
  gap: 3px;
  padding: 14px 16px;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  transition: border-color 0.2s var(--ease), background 0.2s var(--ease), transform 0.2s var(--ease), box-shadow 0.2s var(--ease);
}

.concept-nav-link:hover { border-color: var(--accent); background: var(--bg-hover); text-decoration: none; transform: translateY(-1px); box-shadow: var(--shadow-sm); }
.concept-nav-next { text-align: right; align-items: flex-end; }

.concept-nav-dir { font-size: 11px; text-transform: uppercase; letter-spacing: 0.08em; font-weight: 700; color: var(--accent); }
.concept-nav-title { font-size: 14px; font-weight: 650; color: var(--text); }

/* ---------- Flashcards ---------- */

.flashcard { perspective: 1600px; height: 340px; cursor: pointer; margin-bottom: 16px; }

.flashcard-inner {
  position: relative;
  width: 100%; height: 100%;
  transition: transform 0.5s cubic-bezier(0.4, 0.2, 0.2, 1);
  transform-style: preserve-3d;
}

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

.flashcard-face {
  position: absolute;
  inset: 0;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  background: var(--bg-elev);
  padding: 26px;
  display: flex;
  flex-direction: column;
  overflow-y: auto;
}

.flashcard-back { transform: rotateY(180deg); background: var(--bg-elev-2); }
.flashcard-label { font-size: 10.5px; text-transform: uppercase; letter-spacing: 0.1em; font-weight: 750; color: var(--text-faint); margin-bottom: 12px; flex-shrink: 0; }
.flashcard-body { font-size: 16px; line-height: 1.6; flex: 1; display: flex; flex-direction: column; justify-content: center; }
.flashcard-body .prose { font-size: 15px; }
.flashcard-hint { font-size: 11.5px; color: var(--text-faint); text-align: center; margin-top: 12px; flex-shrink: 0; }

.rate-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: 8px; margin-bottom: 16px; }
.rate-btn {
  padding: 10px 6px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--border);
  background: var(--bg-elev);
  color: var(--text);
  cursor: pointer;
  font-family: inherit;
  font-size: 12.5px;
  font-weight: 650;
  text-align: center;
  transition: background 0.12s, border-color 0.12s;
}
.rate-btn:hover { border-color: currentColor; }
.rate-btn .rate-key { display: block; font-size: 10px; color: var(--text-faint); font-weight: 600; margin-top: 2px; }
.rate-again { color: var(--bad); }
.rate-hard { color: var(--warn); }
.rate-good { color: var(--accent); }
.rate-easy { color: var(--good); }

.progress-line { display: flex; align-items: center; gap: 12px; margin-bottom: 14px; font-size: 12.5px; color: var(--text-dim); }
.progress-track { flex: 1; height: 6px; background: var(--bg-elev-2); border-radius: 3px; overflow: hidden; }
.progress-fill { height: 100%; background: linear-gradient(90deg, var(--accent), var(--accent-2)); border-radius: 3px; transition: width 0.3s; }

/* ---------- Quiz ---------- */

.btn-good { border-color: var(--good); color: var(--good); }
.btn-good:hover { background: var(--good-soft); border-color: var(--good); }
.btn-bad { border-color: var(--bad); color: var(--bad); }
.btn-bad:hover { background: var(--bad-soft); border-color: var(--bad); }

.quiz-score-ring { width: 108px; height: 108px; border-radius: 50%; display: grid; place-items: center; margin: 0 auto 16px; }
.quiz-score-inner { width: 86px; height: 86px; border-radius: 50%; background: var(--bg-elev); display: grid; place-items: center; }
.quiz-score-value { font-size: 25px; font-weight: 750; line-height: 1; font-variant-numeric: tabular-nums; }
.quiz-score-label { font-size: 10px; color: var(--text-faint); text-transform: uppercase; letter-spacing: 0.08em; font-weight: 650; }

/* ---------- Misc ---------- */

.empty { text-align: center; padding: 50px 20px; color: var(--text-faint); }
.empty-icon { font-size: 34px; margin-bottom: 10px; opacity: 0.6; }

.breadcrumb { font-size: 12.5px; color: var(--text-faint); margin-bottom: 12px; display: flex; align-items: center; gap: 7px; flex-wrap: wrap; }
.breadcrumb a { color: var(--text-dim); }

.toolbar { display: flex; gap: 9px; align-items: center; flex-wrap: wrap; margin-bottom: 16px; }

.filter-input {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 7px 12px;
  color: var(--text);
  font-size: 13px;
  font-family: inherit;
  outline: none;
  min-width: 200px;
}
.filter-input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); }

.divider { height: 1px; background: var(--border); margin: 22px 0; }

.muted { color: var(--text-dim); }
.faint { color: var(--text-faint); }
.small { font-size: 12.5px; }
.mono { font-family: var(--mono); }
.mb-0 { margin-bottom: 0; }
.mt-16 { margin-top: 16px; }
.mt-24 { margin-top: 24px; }
.flex { display: flex; }
.flex-between { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.gap-8 { gap: 8px; }
.gap-12 { gap: 12px; }

.track-card { background: var(--bg-elev); border: 1px solid var(--border); border-radius: var(--radius); padding: 16px; }
.track-head { display: flex; align-items: center; gap: 10px; margin-bottom: 10px; }
.track-num { width: 28px; height: 28px; border-radius: 8px; background: var(--accent-soft); color: var(--accent); display: grid; place-items: center; font-weight: 750; font-size: 12.5px; flex-shrink: 0; }
.track-title { font-weight: 680; font-size: 14.5px; }
.track-steps { display: flex; flex-direction: column; gap: 3px; }
.track-step {
  display: flex; align-items: baseline; gap: 9px;
  padding: 5px 8px; border-radius: 6px; font-size: 13px;
  color: var(--text-dim); cursor: pointer; border: none; background: none;
  text-align: left; font-family: inherit; width: 100%;
}
.track-step:hover { background: var(--bg-hover); color: var(--text); text-decoration: none; }
.track-step-num { font-size: 11px; color: var(--text-faint); font-variant-numeric: tabular-nums; min-width: 18px; }
.track-step.done .track-step-name { color: var(--good); }
.track-step.done .track-step-num::after { content: " ✓"; }

.checkbox {
  width: 17px; height: 17px; border-radius: 5px;
  border: 1.5px solid var(--border);
  display: grid; place-items: center;
  cursor: pointer; flex-shrink: 0;
  background: var(--bg-elev);
  font-size: 11px; color: transparent;
  transition: background 0.12s, border-color 0.12s;
}
.checkbox:hover { border-color: var(--accent); }
.checkbox.checked { background: var(--good); border-color: var(--good); color: #fff; }

.toast {
  position: fixed;
  bottom: 22px;
  left: 50%;
  transform: translateX(-50%) translateY(80px);
  background: var(--bg-elev-2);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 10px 18px;
  font-size: 13.5px;
  font-weight: 600;
  box-shadow: var(--shadow);
  opacity: 0;
  transition: transform 0.25s, opacity 0.25s;
  z-index: 100;
  pointer-events: none;
}
.toast.show { transform: translateX(-50%) translateY(0); opacity: 1; }

.mobile-toggle { display: none; }

/* ---------- Responsive ---------- */

@media (max-width: 900px) {
  .app { grid-template-columns: 1fr; }
  .sidebar {
    position: fixed;
    left: 0; top: 0; bottom: 0;
    width: var(--sidebar-w);
    z-index: 60;
    transform: translateX(-100%);
    transition: transform 0.22s ease;
    box-shadow: var(--shadow);
  }
  .sidebar.open { transform: translateX(0); }
  .mobile-toggle { display: grid; }
  .content { padding: 18px 16px; }
  .topbar { padding: 10px 16px; }
  h1 { font-size: 22px; }
  .flashcard { height: 300px; }
  .rate-row { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 560px) {
  .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .section-row { grid-template-columns: 26px 1fr auto; gap: 9px; padding: 10px; }
  .section-name { font-size: 12.5px; }
}

@media print {
  .sidebar, .topbar, .rate-row, .toolbar { display: none; }
  .app { grid-template-columns: 1fr; }
}