:root {
  --bg: #0a1116;
  --surface: rgba(18, 26, 33, 0.92);
  --surface2: rgba(24, 34, 44, 0.9);
  --border: rgba(151, 190, 181, 0.1);
  --border-hover: rgba(181, 156, 255, 0.28);
  --accent: #b59cff;
  --accent2: #58d7ff;
  --accent3: #ff8392;
  --accent4: #ffd56b;
  --text: #e9f0ec;
  --text-muted: #94a59f;
  --muted: #94a59f;
  --code-bg: #111922;
  --green: #7bf0be;
  --orange: #ffbc72;
  --red: #ff8392;
  --nav-h: 64px;
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.25);
  --radius: 20px;
  --radius-sm: 14px;
  --nav-accent: var(--accent);
}

body {
  font-family: "Inter", system-ui, sans-serif;
  background:
    radial-gradient(
      ellipse 60% 50% at 20% 20%,
      rgba(181, 156, 255, 0.06),
      transparent
    ),
    radial-gradient(
      ellipse 50% 40% at 80% 30%,
      rgba(88, 215, 255, 0.05),
      transparent
    ),
    linear-gradient(180deg, #081016 0%, #0b141c 50%, #081015 100%);
  color: var(--text);
  min-height: 100vh;
  padding-top: var(--nav-h);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ── Header ── */
header {
  background: linear-gradient(
    135deg,
    rgba(26, 29, 39, 0.9) 0%,
    rgba(18, 21, 42, 0.9) 100%
  );
  border-bottom: 1px solid var(--border);
  padding: 24px 32px 0;
  backdrop-filter: blur(16px);
}

.header-top {
  display: flex;
  align-items: center;
  gap: 16px;
  margin-bottom: 8px;
}

.badge {
  background: var(--accent);
  color: #fff;
  font-size: 11px;
  padding: 3px 10px;
  border-radius: 20px;
  letter-spacing: 0.5px;
  font-weight: 600;
}

header h1 {
  font-size: 1.5rem;
  font-weight: 700;
}

header p {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 4px;
  margin-bottom: 16px;
}

/* ── Tabs ── */
.tabs {
  display: flex;
  gap: 0;
  border-bottom: none;
  overflow-x: auto;
}

.tab-btn {
  padding: 10px 22px;
  border: none;
  background: transparent;
  color: var(--text-muted);
  font-size: 0.9rem;
  cursor: pointer;
  border-bottom: 3px solid transparent;
  white-space: nowrap;
  transition: all 0.2s;
}

.tab-btn:hover {
  color: var(--text);
}

.tab-btn.active {
  color: var(--accent);
  border-bottom-color: var(--accent);
  font-weight: 600;
}

/* ── Content ── */
.tab-content {
  display: none;
  padding: 32px;
  max-width: 960px;
  margin: 0 auto;
}

.tab-content.active {
  display: block;
}

/* ── Cards ── */
.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-sm);
  padding: 24px;
  margin-bottom: 20px;
  backdrop-filter: blur(16px);
  box-shadow: var(--shadow);
  transition:
    border-color 0.3s ease,
    transform 0.3s cubic-bezier(0.22, 1, 0.36, 1);
}

.card-title {
  font-size: 1rem;
  font-weight: 700;
  margin-bottom: 14px;
  display: flex;
  align-items: center;
  gap: 8px;
}

/* ── Priority badges ── */
.priority-red {
  color: var(--red);
}

.priority-orange {
  color: var(--orange);
}

.priority-green {
  color: var(--green);
}

/* ── Lists ── */
ul.styled,
ol.styled {
  padding-left: 0;
  list-style: none;
}

ul.styled li,
ol.styled li {
  padding: 6px 0 6px 20px;
  position: relative;
  color: var(--text-muted);
  font-size: 0.9rem;
  line-height: 1.6;
}

ul.styled li::before {
  content: "▸";
  position: absolute;
  left: 0;
  color: var(--accent);
}

ol.styled {
  counter-reset: li;
}

ol.styled li {
  counter-increment: li;
}

ol.styled li::before {
  content: counter(li) ".";
  position: absolute;
  left: 0;
  color: var(--accent);
  font-weight: 700;
}

/* ── Code ── */
pre {
  background: var(--code-bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 16px;
  overflow-x: auto;
  font-size: 0.82rem;
  line-height: 1.7;
  margin: 12px 0;
}

code {
  font-family:
    "JetBrains Mono", "Cascadia Code", "Fira Code", "Consolas", monospace;
  color: #a8d8a8;
}

.code-label {
  font-size: 0.75rem;
  color: var(--accent2);
  font-weight: 600;
  margin: 16px 0 4px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

/* ── Tables ── */
table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}

th {
  background: var(--surface2);
  color: var(--accent);
  padding: 10px 14px;
  text-align: left;
  font-weight: 600;
  border-bottom: 2px solid var(--border);
}

td {
  padding: 9px 14px;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
}

tr:last-child td {
  border-bottom: none;
}

/* ── Math block ── */
.math {
  background: var(--code-bg);
  border-left: 3px solid var(--accent);
  padding: 12px 16px;
  border-radius: 4px;
  font-size: 0.9rem;
  margin: 12px 0;
  color: #c9d1d9;
  font-family: "Cambria Math", Georgia, serif;
}

/* ── Quote ── */
.quote {
  border-left: 3px solid var(--accent2);
  background: rgba(0, 212, 170, 0.06);
  padding: 14px 18px;
  border-radius: 0 8px 8px 0;
  margin: 14px 0;
  font-style: italic;
  color: var(--text);
  font-size: 0.9rem;
  line-height: 1.7;
}

/* ── Accordion (mock interview) ── */
.accordion {
  margin-bottom: 12px;
}

.accordion-header {
  background: var(--surface2);
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 14px 18px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.92rem;
  font-weight: 600;
  transition: background 0.2s;
}

.accordion-header:hover {
  background: #282d45;
}

.accordion-arrow {
  transition: transform 0.25s;
  color: var(--accent);
}

.accordion.open .accordion-arrow {
  transform: rotate(180deg);
}

.accordion-body {
  display: none;
  background: var(--surface);
  border: 1px solid var(--border);
  border-top: none;
  border-radius: 0 0 8px 8px;
  padding: 18px;
  font-size: 0.9rem;
  line-height: 1.75;
  color: var(--text-muted);
}

.accordion.open .accordion-body {
  display: block;
}

/* ── Checklist ── */
.check-item {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  padding: 10px 0;
  border-bottom: 1px solid var(--border);
}

.check-item:last-child {
  border-bottom: none;
}

.check-item input[type="checkbox"] {
  margin-top: 3px;
  accent-color: var(--accent);
  width: 16px;
  height: 16px;
  cursor: pointer;
}

.check-item label {
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--text-muted);
  line-height: 1.5;
}

.check-item input:checked + label {
  text-decoration: line-through;
  color: #4a5278;
}

/* ── Week header ── */
.week-header {
  background: linear-gradient(90deg, var(--accent) 0%, #9c88ff 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  font-size: 1rem;
  font-weight: 700;
  margin: 20px 0 8px;
}

/* ── Progress bar ── */
.progress-wrap {
  background: var(--border);
  border-radius: 4px;
  height: 6px;
  margin: 6px 0 2px;
}

.progress-bar {
  background: var(--accent);
  height: 6px;
  border-radius: 4px;
  transition: width 0.3s;
}

.progress-label {
  font-size: 0.75rem;
  color: var(--text-muted);
}

/* ── Tag ── */
.tag {
  display: inline-block;
  background: rgba(108, 99, 255, 0.18);
  color: var(--accent);
  font-size: 0.75rem;
  padding: 2px 8px;
  border-radius: 4px;
  margin: 2px 3px;
}

.tag.green {
  background: rgba(0, 212, 170, 0.12);
  color: var(--accent2);
}

.tag.red {
  background: rgba(244, 67, 54, 0.12);
  color: #ff7070;
}

.tag.yellow {
  background: rgba(255, 209, 102, 0.12);
  color: var(--accent4);
}

/* ── Grid ── */
.grid2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

@media (max-width: 660px) {
  .grid2 {
    grid-template-columns: 1fr;
  }

  .tab-btn {
    padding: 10px 14px;
    font-size: 0.82rem;
  }
}