:root {
  --ink: #0b1220;
  --ink-2: #121c2e;
  --panel: rgba(18, 28, 46, 0.72);
  --line: rgba(126, 231, 196, 0.18);
  --mint: #7ee7c4;
  --mint-dim: #3d9f84;
  --coral: #ff6b6b;
  --amber: #f0c75e;
  --text: #e8eef7;
  --muted: #8b9bb4;
  --radius: 14px;
  --font-display: "Syne", sans-serif;
  --font-mono: "IBM Plex Mono", ui-monospace, monospace;
}

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

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

body {
  font-family: var(--font-mono);
  color: var(--text);
  background:
    radial-gradient(1200px 700px at 10% -10%, #16324a 0%, transparent 55%),
    radial-gradient(900px 600px at 100% 0%, #1a3d36 0%, transparent 50%),
    linear-gradient(165deg, #071018 0%, var(--ink) 45%, #0a1628 100%);
  background-attachment: fixed;
  line-height: 1.5;
}

.noise {
  pointer-events: none;
  position: fixed;
  inset: 0;
  opacity: 0.04;
  background-image: url("data:image/svg+xml,%3Csvg viewBox='0 0 200 200' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.85' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
  z-index: 0;
}

.glow {
  pointer-events: none;
  position: fixed;
  width: 40vw;
  height: 40vw;
  top: 20%;
  right: -10%;
  background: radial-gradient(circle, rgba(126, 231, 196, 0.12), transparent 65%);
  filter: blur(40px);
  z-index: 0;
  animation: drift 14s ease-in-out infinite alternate;
}

@keyframes drift {
  from { transform: translate(-4%, -2%); }
  to { transform: translate(3%, 4%); }
}

#app {
  position: relative;
  z-index: 1;
  width: min(920px, calc(100% - 2rem));
  margin: 0 auto;
  padding: 2.5rem 0 4rem;
}

.screen[hidden] {
  display: none !important;
}

.screen.active {
  animation: rise 0.45s ease both;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

.brand {
  margin-bottom: 1.75rem;
}

.brand.compact {
  margin-bottom: 1.25rem;
}

.brand-mark {
  margin: 0 0 0.35rem;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: clamp(2.4rem, 7vw, 4.2rem);
  letter-spacing: -0.04em;
  line-height: 0.95;
  background: linear-gradient(120deg, var(--mint) 0%, #b8fff0 40%, #9ad7ff 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.brand h1 {
  margin: 0;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: clamp(1.35rem, 3vw, 1.85rem);
  letter-spacing: -0.02em;
}

.lede {
  margin: 0.75rem 0 0;
  max-width: 36rem;
  color: var(--muted);
  font-size: 0.95rem;
}

.meta-row {
  display: inline-flex;
  gap: 0.75rem;
  align-items: center;
  margin-bottom: 1.5rem;
  padding: 0.45rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--mint);
  font-size: 0.78rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
}

.modes {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.85rem;
}

@media (max-width: 640px) {
  .modes {
    grid-template-columns: 1fr;
  }
}

.mode {
  text-align: left;
  padding: 1.15rem 1.2rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
  backdrop-filter: blur(10px);
  color: inherit;
  cursor: pointer;
  transition: border-color 0.2s, transform 0.2s, background 0.2s;
}

.mode-practice-wrap {
  display: grid;
  gap: 0.55rem;
}
.mode.mode-heading {
  cursor: default;
  pointer-events: none;
}
.mode.has-resume {
  border-color: rgba(61, 255, 168, 0.45);
  box-shadow: inset 0 0 0 1px rgba(61, 255, 168, 0.12);
}
.mode.has-resume .mode-desc {
  color: var(--accent, #3dffa8);
}
.practice-sets {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(9.5rem, 1fr));
  gap: 0.45rem 0.55rem;
  align-items: start;
}
.practice-set-cell {
  display: grid;
  gap: 0.2rem;
}
.practice-set {
  text-align: left;
  padding: 0.7rem 0.8rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: rgba(10, 18, 16, 0.55);
  color: inherit;
  cursor: pointer;
  font: inherit;
  transition: border-color 0.2s, transform 0.2s, background 0.2s;
}
.practice-set:hover {
  border-color: rgba(126, 231, 196, 0.55);
  transform: translateY(-1px);
  background: rgba(22, 36, 58, 0.9);
}
.practice-set.has-resume {
  border-color: rgba(61, 255, 168, 0.45);
}
.practice-set-title {
  display: block;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 0.95rem;
  margin-bottom: 0.2rem;
}
.practice-set-meta {
  display: block;
  color: var(--muted);
  font-size: 0.72rem;
  line-height: 1.35;
}
.practice-set.has-resume .practice-set-meta {
  color: var(--accent, #3dffa8);
}
.practice-set-restart {
  display: block;
  margin-top: 0.35rem;
  padding: 0;
  border: none;
  background: none;
  color: var(--muted);
  font: inherit;
  font-size: 0.68rem;
  text-decoration: underline;
  text-underline-offset: 2px;
  cursor: pointer;
}
.practice-set-restart:hover {
  color: var(--mint);
}
.mode:hover:not(:disabled) {
  border-color: rgba(126, 231, 196, 0.55);
  transform: translateY(-2px);
  background: rgba(22, 36, 58, 0.9);
}

.mode:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.mode-kicker {
  display: block;
  color: var(--mint-dim);
  font-size: 0.72rem;
  letter-spacing: 0.12em;
  margin-bottom: 0.35rem;
}

.mode-title {
  display: block;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.25rem;
  margin-bottom: 0.35rem;
}

.mode-desc {
  display: block;
  color: var(--muted);
  font-size: 0.82rem;
}

.home-foot {
  display: flex;
  justify-content: space-between;
  gap: 1rem;
  align-items: center;
  margin-top: 1.75rem;
  color: var(--muted);
  font-size: 0.8rem;
}

.linkish {
  background: none;
  border: none;
  color: var(--muted);
  text-decoration: underline;
  text-underline-offset: 3px;
  cursor: pointer;
  font: inherit;
  padding: 0;
}

.linkish:hover {
  color: var(--mint);
}

.install-hint {
  margin: 1.25rem 0 0;
  color: var(--muted);
  font-size: 0.8rem;
  line-height: 1.45;
  max-width: 36rem;
}

.install-btn {
  margin-top: 0.75rem;
}

.quiz-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  margin-bottom: 0.85rem;
}

.hud {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
  font-size: 0.75rem;
  color: var(--muted);
}

.hud span {
  padding: 0.25rem 0.55rem;
  border: 1px solid var(--line);
  border-radius: 999px;
}

#hud-timer {
  font-variant-numeric: tabular-nums;
  font-weight: 600;
  color: var(--mint);
}

#hud-timer.warn {
  color: #ffc857;
  border-color: rgba(255, 200, 87, 0.45);
}

#hud-timer.danger {
  color: #ff6b6b;
  border-color: rgba(255, 107, 107, 0.55);
}

.progress-track {
  height: 3px;
  background: rgba(255, 255, 255, 0.06);
  border-radius: 999px;
  overflow: hidden;
  margin-bottom: 1.25rem;
}

.progress-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--mint-dim), var(--mint));
  transition: width 0.35s ease;
}

.q-card {
  padding: 1.35rem 1.4rem 1.2rem;
  border: 1px solid var(--line);
  border-radius: calc(var(--radius) + 4px);
  background: var(--panel);
  backdrop-filter: blur(12px);
}

.q-meta-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-bottom: 0.65rem;
}
.q-meta {
  margin: 0;
  color: var(--mint);
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
.ghost.small {
  padding: 0.4rem 0.85rem;
  font-size: 0.78rem;
  border-color: rgba(126, 231, 196, 0.45);
  color: var(--mint);
  flex-shrink: 0;
}
.ghost.small:hover:not(:disabled) {
  background: rgba(126, 231, 196, 0.12);
}
#q-edit[hidden] {
  display: none !important;
}
#q-edit:not([hidden]) {
  display: block;
}
.edit-label {
  display: block;
  margin: 0.35rem 0 0.35rem;
  color: var(--muted);
  font-size: 0.72rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}
#edit-question {
  width: 100%;
  min-height: 7rem;
  resize: vertical;
  font: inherit;
  color: inherit;
  background: rgba(8, 14, 24, 0.55);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.75rem 0.85rem;
  line-height: 1.45;
  margin-bottom: 0.75rem;
}
.edit-opts {
  display: grid;
  gap: 0.5rem;
}
.edit-opt {
  display: grid;
  grid-template-columns: auto 1.5rem 1fr;
  gap: 0.55rem;
  align-items: center;
}
.edit-opt input[type="text"] {
  width: 100%;
  font: inherit;
  color: inherit;
  background: rgba(8, 14, 24, 0.55);
  border: 1px solid var(--line);
  border-radius: 10px;
  padding: 0.65rem 0.75rem;
}
.edit-opt label {
  color: var(--mint);
  font-size: 0.8rem;
  font-weight: 600;
}
.edit-status {
  margin: 0.75rem 0 0;
  font-size: 0.82rem;
}
.edit-status.ok { color: var(--mint); }
.edit-status.err { color: #ffb4b4; }

.q-text {
  margin: 0 0 1.15rem;
  font-family: var(--font-display);
  font-weight: 600;
  font-size: clamp(1.05rem, 2.4vw, 1.28rem);
  line-height: 1.45;
  letter-spacing: -0.015em;
}

.options {
  display: grid;
  gap: 0.55rem;
}

.opt {
  display: grid;
  grid-template-columns: auto 1fr;
  gap: 0.75rem;
  align-items: start;
  width: 100%;
  text-align: left;
  padding: 0.85rem 0.95rem;
  border: 1px solid rgba(139, 155, 180, 0.25);
  border-radius: 12px;
  background: rgba(8, 14, 24, 0.45);
  color: inherit;
  font: inherit;
  cursor: pointer;
  transition: border-color 0.15s, background 0.15s;
}

.opt:hover:not(:disabled) {
  border-color: rgba(126, 231, 196, 0.45);
}

.opt:disabled {
  cursor: default;
}

.opt .letter {
  display: inline-flex;
  width: 1.6rem;
  height: 1.6rem;
  align-items: center;
  justify-content: center;
  border-radius: 6px;
  border: 1px solid var(--line);
  color: var(--mint);
  font-size: 0.78rem;
  font-weight: 600;
}

.opt.selected {
  border-color: rgba(126, 231, 196, 0.7);
  background: rgba(126, 231, 196, 0.08);
}

.opt.correct {
  border-color: rgba(126, 231, 196, 0.85);
  background: rgba(126, 231, 196, 0.12);
}

.opt.wrong {
  border-color: rgba(255, 107, 107, 0.75);
  background: rgba(255, 107, 107, 0.1);
}

.feedback {
  margin-top: 0.9rem;
  padding: 0.75rem 0.9rem;
  border-radius: 10px;
  font-size: 0.88rem;
}

.feedback.ok {
  background: rgba(126, 231, 196, 0.12);
  color: var(--mint);
}

.feedback.bad {
  background: rgba(255, 107, 107, 0.12);
  color: #ffb4b4;
}

.q-actions {
  margin-top: 1rem;
  display: flex;
  justify-content: flex-end;
  gap: 0.55rem;
  flex-wrap: wrap;
}

.primary,
.ghost {
  font: inherit;
  cursor: pointer;
  border-radius: 999px;
  padding: 0.7rem 1.2rem;
  transition: transform 0.15s, opacity 0.15s, background 0.15s;
}

.primary {
  border: none;
  background: linear-gradient(120deg, #5fd4ad, #7ee7c4 50%, #9ad7ff);
  color: #062018;
  font-weight: 600;
}

.primary:hover:not(:disabled) {
  transform: translateY(-1px);
}

.primary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.ghost {
  border: 1px solid var(--line);
  background: transparent;
  color: var(--text);
}

.ghost:hover {
  border-color: rgba(126, 231, 196, 0.5);
}

.hint {
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: 0.75rem;
  text-align: center;
}

kbd {
  display: inline-block;
  padding: 0.05rem 0.35rem;
  border: 1px solid var(--line);
  border-radius: 4px;
  font: inherit;
  font-size: 0.7rem;
}

.results-grid {
  display: grid;
  grid-template-columns: repeat(3, minmax(0, 1fr));
  gap: 0.75rem;
  margin-bottom: 1.5rem;
}

@media (max-width: 560px) {
  .results-grid {
    grid-template-columns: 1fr;
  }
}

.stat {
  padding: 1rem 1.1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.stat .label {
  display: block;
  color: var(--muted);
  font-size: 0.72rem;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  margin-bottom: 0.35rem;
}

.stat .value {
  font-family: var(--font-display);
  font-size: 1.8rem;
  font-weight: 700;
}

.results-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.65rem;
}

.results-review {
  margin: 0 0 1.5rem;
}

.review-heading {
  font-family: var(--font-display);
  font-size: 1.15rem;
  font-weight: 700;
  margin: 0 0 0.35rem;
}

.review-lede {
  color: var(--muted);
  font-size: 0.85rem;
  margin: 0 0 1rem;
}

.review-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 0.75rem;
}

.review-item {
  padding: 0.9rem 1rem;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--panel);
}

.review-q {
  margin: 0 0 0.55rem;
  font-size: 0.92rem;
  line-height: 1.45;
}

.review-id {
  color: var(--mint-dim);
  font-family: var(--font-mono, var(--font-display));
  font-size: 0.75rem;
  letter-spacing: 0.06em;
  margin-right: 0.35rem;
}

.review-ans {
  margin: 0.25rem 0 0;
  font-size: 0.8rem;
  line-height: 1.4;
}

.review-ans.wrong {
  color: #ff8f8f;
}

.review-ans.right {
  color: var(--mint, #3dffa8);
}