:root {
  --bg: #f5f7fb;
  --fg: #1b2230;
  --card: #ffffff;
  --muted: #6d7788;
  --primary: #1677ff;
  --accent: #0ea5a8;
  --border: #dbe2ee;
}
:root[data-theme='dark'] {
  --bg: #111623;
  --fg: #f5f8ff;
  --card: #192235;
  --muted: #9ba7be;
  --primary: #5ba0ff;
  --accent: #38d6d8;
  --border: #2a3550;
}
* { box-sizing: border-box; }
body { margin: 0; font-family: 'Segoe UI', Tahoma, sans-serif; background: radial-gradient(circle at top, #eaf2ff, var(--bg)); color: var(--fg); }
:root[data-theme='dark'] body { background: radial-gradient(circle at top, #1e2640, var(--bg)); }
.topbar { display: flex; gap: .5rem; align-items: center; justify-content: space-between; padding: .8rem 1rem; border-bottom: 1px solid var(--border); background: var(--card); position: sticky; top: 0; z-index: 20; }
.brand { font-weight: 800; }
.tabs { display: grid; grid-template-columns: repeat(4, 1fr); gap: .35rem; padding: .6rem; background: var(--bg); position: sticky; top: 57px; z-index: 19; }
.tabs a { text-decoration: none; color: var(--fg); background: var(--card); border: 1px solid var(--border); border-radius: 10px; text-align: center; padding: .55rem .35rem; font-size: .9rem; }
.container { max-width: 980px; margin: 0 auto; padding: 1rem; }
.grid { display: grid; gap: .8rem; }
.grid.cards { grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); }
.card { background: var(--card); border: 1px solid var(--border); border-radius: 14px; padding: .9rem; box-shadow: 0 6px 20px rgba(0,0,0,.04); }
.metric { font-size: 1.7rem; font-weight: 800; margin: .2rem 0; }
input, select, button { width: 100%; border: 1px solid var(--border); background: #fff; border-radius: 10px; padding: .65rem; font-size: 1rem; }
:root[data-theme='dark'] input, :root[data-theme='dark'] select, :root[data-theme='dark'] button { background: #141d2d; color: var(--fg); }
button, .btn { background: linear-gradient(120deg, var(--primary), var(--accent)); color: #fff; text-decoration: none; display: inline-block; border: 0; padding: .7rem .9rem; border-radius: 10px; cursor: pointer; }
.row { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: .6rem; align-items: center; margin-bottom: .6rem; }
.list { display: grid; gap: .7rem; }
.bar-row { display: grid; grid-template-columns: 120px 1fr auto; gap: .6rem; align-items: center; margin-bottom: .45rem; }
.bar { background: #dbe7ff; border-radius: 99px; overflow: hidden; height: 14px; }
.bar i { display: block; height: 100%; background: linear-gradient(120deg, var(--primary), var(--accent)); }
.review-card { min-height: 240px; display: grid; place-items: center; font-size: 1.5rem; font-weight: 700; text-align: center; position: relative; transform-style: preserve-3d; transition: transform .4s; }
.review-card.flipped { transform: rotateY(180deg); }
.review-card .front, .review-card .back { position: absolute; backface-visibility: hidden; }
.review-card .back { transform: rotateY(180deg); }
.grade-row { display: grid; grid-template-columns: repeat(4, 1fr); gap: .5rem; }
.sticky-bottom { position: sticky; bottom: .5rem; padding: .5rem; background: var(--bg); }
.hint { color: var(--muted); font-size: .9rem; }
.prompt { font-size: 1.8rem; letter-spacing: .08em; text-align: center; font-weight: 800; margin: .3rem 0 .7rem; }
.error { color: #e11d48; }
@media (max-width: 740px) { .row { grid-template-columns: 1fr; } .tabs { grid-template-columns: repeat(3, 1fr); } }

.table { width: 100%; border-collapse: collapse; }
.table th, .table td { border-bottom: 1px solid var(--border); padding: .5rem; text-align: left; }
.table code { font-size: .9rem; }
.actions { display: flex; gap: .5rem; flex-wrap: wrap; }