:root {
  --bg0: #f3efe6;
  --bg1: #e7f0ea;
  --ink: #1c2a24;
  --muted: #5a6b63;
  --math: #0f6b4c;
  --math-soft: #d7efe4;
  --rus: #8a4b1f;
  --rus-soft: #f3e2d2;
  --card: rgba(255, 255, 255, 0.72);
  --line: rgba(28, 42, 36, 0.12);
  --ok: #1f7a45;
  --bad: #a33b2d;
  --warn: #9a6b00;
  --shadow: 0 18px 50px rgba(28, 42, 36, 0.08);
  --radius: 18px;
  --font: "Manrope", sans-serif;
  --display: "Literata", Georgia, serif;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: var(--font);
  color: var(--ink);
  background:
    radial-gradient(1200px 600px at 10% -10%, #dff3ea 0%, transparent 55%),
    radial-gradient(900px 500px at 100% 0%, #f7e7d4 0%, transparent 50%),
    linear-gradient(180deg, var(--bg0), var(--bg1));
  min-height: 100vh;
  line-height: 1.55;
}

.skip {
  position: absolute;
  left: -999px;
  top: 0;
  background: #000;
  color: #fff;
  padding: 8px 12px;
}
.skip:focus { left: 8px; z-index: 20; }

.container {
  width: min(980px, calc(100% - 2rem));
  margin: 0 auto;
}

.site-header {
  padding: 2rem 0 1rem;
}
.header-row {
  display: flex;
  justify-content: space-between;
  gap: 1.5rem;
  align-items: end;
  flex-wrap: wrap;
}
.brand {
  margin: 0;
  text-transform: uppercase;
  letter-spacing: 0.12em;
  font-size: 0.75rem;
  color: var(--muted);
  font-weight: 700;
}
.site-header h1 {
  font-family: var(--display);
  font-size: clamp(1.8rem, 4vw, 2.6rem);
  margin: 0.2rem 0;
  line-height: 1.15;
}
.tagline { margin: 0; color: var(--muted); max-width: 36rem; }
.header-stats {
  display: flex;
  gap: 0.75rem;
  flex-wrap: wrap;
}
.stat-pill {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 0.55rem 0.9rem;
  font-size: 0.9rem;
  backdrop-filter: blur(8px);
}

.site-footer {
  padding: 2rem 0 3rem;
  color: var(--muted);
  font-size: 0.9rem;
}
.site-footer a { color: var(--math); }

.panel {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  padding: 1.25rem 1.35rem;
  margin: 1rem 0;
}

.home-intro {
  display: grid;
  gap: 1rem;
  grid-template-columns: 1.4fr 1fr;
}
@media (max-width: 800px) {
  .home-intro { grid-template-columns: 1fr; }
}

.day-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(150px, 1fr));
  gap: 0.75rem;
  margin: 1rem 0 2rem;
}
.day-card {
  display: block;
  text-decoration: none;
  color: inherit;
  border-radius: 16px;
  padding: 0.9rem;
  border: 1px solid var(--line);
  background: rgba(255,255,255,0.65);
  transition: transform 0.18s ease, box-shadow 0.18s ease;
  min-height: 118px;
}
.day-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow);
}
.day-card.math { border-top: 4px solid var(--math); }
.day-card.russian { border-top: 4px solid var(--rus); }
.day-card.done { background: linear-gradient(180deg, #eef8f1, #fff); }
.day-card .num {
  font-family: var(--display);
  font-size: 1.4rem;
  margin: 0;
}
.day-card .meta {
  margin: 0.35rem 0 0;
  font-size: 0.82rem;
  color: var(--muted);
}
.day-card .title {
  margin: 0.35rem 0 0;
  font-size: 0.92rem;
  font-weight: 600;
}
.badge {
  display: inline-block;
  font-size: 0.72rem;
  font-weight: 700;
  padding: 0.15rem 0.45rem;
  border-radius: 999px;
  margin-top: 0.4rem;
}
.badge.math { background: var(--math-soft); color: var(--math); }
.badge.russian { background: var(--rus-soft); color: var(--rus); }
.badge.exam { background: #f6e7a8; color: #6d5400; }

.toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 0.6rem;
  align-items: center;
  justify-content: space-between;
  margin: 1rem 0;
}
.timer-box {
  display: flex;
  align-items: center;
  gap: 0.6rem;
  background: #12231c;
  color: #e8fff4;
  border-radius: 999px;
  padding: 0.45rem 0.55rem 0.45rem 1rem;
  font-variant-numeric: tabular-nums;
}
.timer-box.danger { background: #5c1d18; }
.timer-box .time {
  font-family: var(--display);
  font-size: 1.25rem;
  min-width: 5.5rem;
}
.btn {
  border: 0;
  border-radius: 999px;
  padding: 0.55rem 1rem;
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  background: var(--ink);
  color: #fff;
}
.btn:hover { filter: brightness(1.08); }
.btn.secondary {
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--line);
}
.btn.math { background: var(--math); }
.btn.rus { background: var(--rus); }
.btn:disabled { opacity: 0.5; cursor: not-allowed; }

.lesson-hero h2 {
  font-family: var(--display);
  margin: 0.2rem 0;
  font-size: clamp(1.4rem, 3vw, 2rem);
}
.goals { margin: 0.5rem 0 0; padding-left: 1.1rem; color: var(--muted); }
.theory-block {
  background: rgba(255,255,255,0.8);
  border-left: 4px solid var(--math);
  padding: 0.9rem 1rem;
  border-radius: 0 12px 12px 0;
  margin: 1rem 0;
}
.lesson-hero.russian .theory-block { border-left-color: var(--rus); }

.task {
  border: 1px solid var(--line);
  border-radius: 14px;
  padding: 1rem;
  margin: 0.85rem 0;
  background: rgba(255,255,255,0.78);
}
.task.correct { border-color: rgba(31,122,69,0.45); background: #f0faf3; }
.task.incorrect { border-color: rgba(163,59,45,0.4); background: #fff4f2; }
.task-head {
  display: flex;
  justify-content: space-between;
  gap: 0.75rem;
  align-items: baseline;
  margin-bottom: 0.4rem;
}
.oge-tag {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--muted);
  white-space: nowrap;
}
.options {
  display: grid;
  gap: 0.4rem;
  margin: 0.6rem 0;
}
.options label {
  display: flex;
  gap: 0.55rem;
  align-items: flex-start;
  padding: 0.45rem 0.6rem;
  border-radius: 10px;
  border: 1px solid transparent;
  cursor: pointer;
}
.options label:hover { background: rgba(28,42,36,0.04); }
.answer-input, .writing-area {
  width: 100%;
  font: inherit;
  padding: 0.65rem 0.75rem;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: #fff;
}
.writing-area { min-height: 140px; resize: vertical; }
.word-count { font-size: 0.85rem; color: var(--muted); margin-top: 0.35rem; }
.feedback {
  margin-top: 0.55rem;
  font-size: 0.92rem;
}
.feedback.ok { color: var(--ok); }
.feedback.bad { color: var(--bad); }
.feedback.soft { color: var(--warn); }
.explanation {
  margin-top: 0.35rem;
  color: var(--muted);
  font-size: 0.9rem;
}

.results {
  position: sticky;
  bottom: 0.75rem;
  background: #12231c;
  color: #eafff4;
  border-radius: 16px;
  padding: 1rem 1.1rem;
  box-shadow: var(--shadow);
  display: none;
}
.results.show { display: block; animation: rise 0.35s ease; }
@keyframes rise {
  from { transform: translateY(12px); opacity: 0; }
  to { transform: translateY(0); opacity: 1; }
}

.progress-bar {
  height: 8px;
  background: rgba(255,255,255,0.15);
  border-radius: 999px;
  overflow: hidden;
  margin-top: 0.55rem;
}
.progress-bar > span {
  display: block;
  height: 100%;
  background: linear-gradient(90deg, #7dffb2, #2fcaa0);
  width: 0;
}

.nav-links { display: flex; gap: 0.5rem; flex-wrap: wrap; margin-top: 1rem; }

@media (prefers-reduced-motion: reduce) {
  * { transition: none !important; animation: none !important; }
}