:root {
  --bg: #080b16;
  --panel: rgba(255,255,255,0.07);
  --panel-strong: rgba(255,255,255,0.11);
  --text: rgba(255,255,255,0.94);
  --muted: rgba(255,255,255,0.64);
  --line: rgba(255,255,255,0.14);
  --good: #49d17d;
  --warn: #ffd166;
  --bad: #ff6b6b;
  --blue: #77a7ff;
  --purple: #c58bff;
  --shadow: 0 20px 80px rgba(0,0,0,0.35);
  --radius: 22px;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  background:
    radial-gradient(circle at top left, rgba(119,167,255,0.25), transparent 35%),
    radial-gradient(circle at top right, rgba(197,139,255,0.20), transparent 35%),
    var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  min-height: 100vh;
}

button,
input,
textarea,
select {
  font: inherit;
}

button {
  cursor: pointer;
}

.app-shell {
  width: min(1180px, calc(100% - 32px));
  margin: 0 auto;
  padding: 32px 0 80px;
}

.hero {
  display: flex;
  justify-content: space-between;
  gap: 24px;
  align-items: stretch;
  margin-bottom: 24px;
}

.eyebrow {
  margin: 0 0 8px;
  color: var(--blue);
  font-size: 0.78rem;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  font-weight: 800;
}

h1,
h2,
h3 {
  margin: 0;
  line-height: 1.05;
}

h1 {
  font-size: clamp(2.4rem, 5vw, 4.6rem);
}

h2 {
  font-size: 1.35rem;
}

h3 {
  font-size: 1.1rem;
}

.subtitle {
  max-width: 720px;
  color: var(--muted);
  font-size: 1.1rem;
}

.status-card,
.panel {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(18px);
}

.status-card {
  min-width: 240px;
  padding: 18px;
  display: flex;
  align-items: center;
  gap: 14px;
  height: fit-content;
}

.status-card span {
  display: block;
  color: var(--muted);
  font-size: 0.88rem;
  margin-top: 3px;
}

.status-dot {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--warn);
  box-shadow: 0 0 18px var(--warn);
}

.status-dot.ok {
  background: var(--good);
  box-shadow: 0 0 18px var(--good);
}

.status-dot.bad {
  background: var(--bad);
  box-shadow: 0 0 18px var(--bad);
}

.panel {
  padding: 22px;
  margin-bottom: 20px;
}

.panel-header {
  margin-bottom: 18px;
}

.spread {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: center;
}

.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 20px;
}

.form-grid {
  display: grid;
  gap: 14px;
}

label {
  color: var(--muted);
  display: grid;
  gap: 8px;
  font-weight: 700;
}

input,
textarea,
select {
  width: 100%;
  border: 1px solid var(--line);
  background: rgba(0,0,0,0.28);
  color: var(--text);
  padding: 12px 13px;
  border-radius: 14px;
  outline: none;
}

textarea {
  min-height: 92px;
  resize: vertical;
}

input:focus,
textarea:focus,
select:focus {
  border-color: rgba(119,167,255,0.9);
  box-shadow: 0 0 0 4px rgba(119,167,255,0.12);
}

.primary,
.secondary,
.tab {
  border: 0;
  border-radius: 14px;
  padding: 12px 16px;
  color: var(--text);
  font-weight: 800;
}

.primary {
  background: linear-gradient(135deg, var(--blue), var(--purple));
}

.secondary {
  background: var(--panel-strong);
  border: 1px solid var(--line);
}

.tabs {
  display: flex;
  gap: 10px;
  margin-bottom: 16px;
}

.tab {
  background: rgba(255,255,255,0.06);
  border: 1px solid var(--line);
}

.tab.active {
  background: rgba(119,167,255,0.22);
  border-color: rgba(119,167,255,0.55);
}

.hidden {
  display: none !important;
}

.message {
  color: var(--muted);
  margin-bottom: 0;
}

.message.error {
  color: var(--bad);
}

.message.success {
  color: var(--good);
}

.muted {
  color: var(--muted);
}

.divider {
  height: 1px;
  background: var(--line);
  margin: 18px 0;
}

.stats-grid,
.bucket-grid {
  display: grid;
  gap: 12px;
}

.stats-grid {
  grid-template-columns: repeat(4, 1fr);
}

.bucket-grid {
  grid-template-columns: repeat(4, 1fr);
  margin-bottom: 18px;
}

.stat,
.bucket,
.mini-summary,
.card-row,
.review-card {
  background: rgba(0,0,0,0.25);
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 16px;
}

.stat span {
  color: var(--muted);
  display: block;
  font-size: 0.88rem;
}

.stat strong {
  font-size: 1.8rem;
}

.bucket {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-weight: 900;
}

.bucket.new {
  border-color: rgba(119,167,255,0.35);
}

.bucket.hard {
  border-color: rgba(255,107,107,0.45);
}

.bucket.medium {
  border-color: rgba(255,209,102,0.45);
}

.bucket.easy {
  border-color: rgba(73,209,125,0.45);
}

.mode-row {
  display: flex;
  gap: 10px;
  align-items: center;
}

.mode-row select {
  min-width: 180px;
}

.review-card.empty {
  color: var(--muted);
}

.review-question {
  font-size: 1.35rem;
  font-weight: 900;
  margin-bottom: 12px;
}

.review-answer {
  white-space: pre-wrap;
  color: var(--good);
  background: rgba(73,209,125,0.08);
  border: 1px solid rgba(73,209,125,0.25);
  padding: 14px;
  border-radius: 14px;
  margin-top: 14px;
}

.review-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin-top: 16px;
}

.cards-list {
  display: grid;
  gap: 12px;
}

.card-row {
  display: grid;
  gap: 8px;
}

.card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.pill {
  display: inline-flex;
  align-items: center;
  border: 1px solid var(--line);
  background: rgba(255,255,255,0.06);
  border-radius: 999px;
  padding: 5px 9px;
  font-size: 0.82rem;
  color: var(--muted);
}

.pill.hard {
  color: var(--bad);
}

.pill.medium {
  color: var(--warn);
}

.pill.easy {
  color: var(--good);
}

.pill.new {
  color: var(--blue);
}

@media (max-width: 880px) {
  .hero,
  .spread {
    flex-direction: column;
  }

  .grid-2,
  .stats-grid,
  .bucket-grid {
    grid-template-columns: 1fr;
  }
}

/* =========================
   App navigation
   ========================= */

.site-nav {
  position: sticky;
  top: 12px;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 18px;
  padding: 12px;
  margin-bottom: 28px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: rgba(8, 11, 22, 0.76);
  backdrop-filter: blur(18px);
  box-shadow: var(--shadow);
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  color: var(--text);
  text-decoration: none;
  font-weight: 900;
  padding: 4px 8px 4px 4px;
}

.brand-mark {
  display: grid;
  place-items: center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue), var(--purple));
  color: white;
  font-size: 0.86rem;
  letter-spacing: -0.04em;
}

.nav-links,
.nav-auth {
  display: flex;
  align-items: center;
  gap: 8px;
}

.nav-link {
  border: 0;
  border-radius: 999px;
  background: transparent;
  color: var(--muted);
  padding: 10px 13px;
  font-weight: 850;
}

.nav-link:hover,
.nav-link.active {
  color: var(--text);
  background: rgba(255,255,255,0.09);
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
}

.feature-card {
  border: 1px solid var(--line);
  border-radius: 18px;
  padding: 18px;
  background: rgba(0,0,0,0.22);
}

.feature-card p {
  color: var(--muted);
  margin-bottom: 0;
}

@media (max-width: 880px) {
  .site-nav {
    position: static;
    border-radius: var(--radius);
    align-items: stretch;
    flex-direction: column;
  }

  .nav-links,
  .nav-auth {
    width: 100%;
    justify-content: center;
    flex-wrap: wrap;
  }

  .feature-grid {
    grid-template-columns: 1fr;
  }
}