:root {
  --bg: #0d0f12;
  --panel: #15181d;
  --panel-2: #1b1f26;
  --border: #262c35;
  --text: #e8eaed;
  --muted: #9aa4b0;
  --accent: #ff8c1a;
  --accent-2: #ffb067;
  --done: #3ddc84;
  --mono: "SFMono-Regular", ui-monospace, "JetBrains Mono", Menlo, Consolas, monospace;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.55;
}

.wrap { max-width: 1080px; margin: 0 auto; padding: 0 24px; }

.site-header {
  border-bottom: 1px solid var(--border);
  background: radial-gradient(1200px 300px at 20% -80px, rgba(255,140,26,.13), transparent 60%), var(--panel);
  padding: 40px 0 28px;
}

.brand-row { display: flex; align-items: baseline; justify-content: space-between; gap: 24px; flex-wrap: wrap; }

.brand {
  margin: 0;
  font-size: 42px;
  letter-spacing: -1.5px;
  font-weight: 800;
}
.accent { color: var(--accent); }

.progress-summary {
  font-family: var(--mono);
  font-size: 15px;
  color: var(--muted);
  text-align: right;
}
.progress-summary .big { color: var(--text); font-size: 22px; }

.overall-bar {
  height: 8px; background: var(--panel-2); border: 1px solid var(--border);
  border-radius: 99px; margin-top: 8px; overflow: hidden; width: 240px;
}
.overall-bar > div { height: 100%; background: linear-gradient(90deg, var(--accent), var(--accent-2)); transition: width .4s; }

.tagline { color: var(--muted); max-width: 720px; margin: 14px 0 0; font-size: 16px; }

.how {
  display: flex; align-items: center; gap: 12px; flex-wrap: wrap;
  margin-top: 24px; padding: 14px 18px;
  background: var(--panel-2); border: 1px solid var(--border); border-radius: 12px;
  font-size: 13.5px;
}
.how-step { display: flex; align-items: center; gap: 8px; }
.how-n {
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; border-radius: 50%;
  background: rgba(255,140,26,.15); color: var(--accent);
  font-family: var(--mono); font-size: 12px; font-weight: 700;
}
.how-arrow { color: var(--muted); }
.muted { color: var(--muted); }

.loading { padding: 60px 0; color: var(--muted); text-align: center; }

.category { margin: 44px 0; }
.cat-head { display: flex; align-items: baseline; justify-content: space-between; gap: 16px; flex-wrap: wrap; }
.cat-title { margin: 0; font-size: 24px; letter-spacing: -.5px; }
.cat-index { color: var(--accent); font-family: var(--mono); font-size: 14px; margin-right: 10px; }
.cat-progress { font-family: var(--mono); color: var(--muted); font-size: 13px; }
.cat-sub { color: var(--muted); margin: 6px 0 0; font-size: 14.5px; }

.cat-bar { height: 5px; background: var(--panel-2); border-radius: 99px; margin: 14px 0 20px; overflow: hidden; }
.cat-bar > div { height: 100%; background: var(--accent); transition: width .4s; }
.cat-bar.complete > div { background: var(--done); }

.exercises { display: grid; grid-template-columns: 1fr 1fr; gap: 16px; }
@media (max-width: 760px) { .exercises { grid-template-columns: 1fr; } }

.ex {
  background: var(--panel); border: 1px solid var(--border); border-radius: 14px;
  padding: 20px 22px; display: flex; flex-direction: column; gap: 12px;
  transition: border-color .15s, transform .15s;
}
.ex:hover { border-color: #354052; }
.ex.done { border-color: rgba(61,220,132,.35); }
.ex.done .ex-title { color: var(--muted); text-decoration: line-through; text-decoration-color: rgba(61,220,132,.6); }

.ex-top { display: flex; justify-content: space-between; align-items: center; gap: 10px; }
.ex-meta { display: flex; align-items: center; gap: 12px; font-family: var(--mono); font-size: 12px; color: var(--muted); }

.diff { display: inline-flex; gap: 3px; }
.diff i { width: 7px; height: 7px; border-radius: 2px; background: var(--panel-2); border: 1px solid var(--border); }
.diff i.on { background: var(--accent); border-color: var(--accent); }

.ex-title { margin: 0; font-size: 17.5px; font-weight: 700; letter-spacing: -.2px; }
.ex-brief { margin: 0; color: var(--muted); font-size: 14px; flex: 1; }

.tags { display: flex; flex-wrap: wrap; gap: 6px; }
.tag {
  font-family: var(--mono); font-size: 11px; color: var(--accent-2);
  background: rgba(255,140,26,.08); border: 1px solid rgba(255,140,26,.22);
  padding: 2px 8px; border-radius: 99px;
}

.ex-actions { display: flex; align-items: center; gap: 10px; margin-top: 4px; flex-wrap: wrap; }

.btn {
  appearance: none; border: 1px solid var(--border); background: var(--panel-2);
  color: var(--text); font-size: 13px; font-weight: 600;
  padding: 8px 14px; border-radius: 9px; cursor: pointer; text-decoration: none;
  display: inline-flex; align-items: center; gap: 7px;
  transition: background .15s, border-color .15s;
}
.btn:hover { border-color: #3b4656; background: #20252e; }
.btn.primary { background: var(--accent); border-color: var(--accent); color: #14100a; }
.btn.primary:hover { background: var(--accent-2); border-color: var(--accent-2); }

.done-toggle {
  margin-left: auto; display: inline-flex; align-items: center; gap: 8px;
  font-size: 13px; color: var(--muted); cursor: pointer; user-select: none;
}
.done-toggle input { display: none; }
.done-box {
  width: 20px; height: 20px; border-radius: 6px; border: 1.5px solid var(--border);
  background: var(--panel-2); display: inline-flex; align-items: center; justify-content: center;
  transition: all .15s; font-size: 13px;
}
.done-toggle input:checked + .done-box { background: var(--done); border-color: var(--done); color: #0a1410; }
.done-box::after { content: "✓"; opacity: 0; }
.done-toggle input:checked + .done-box::after { opacity: 1; }

.recent { margin: 40px 0 0; padding: 16px 20px; background: var(--panel); border: 1px solid var(--border); border-radius: 12px; }
.recent h3 { margin: 0 0 8px; font-size: 14px; color: var(--muted); text-transform: uppercase; letter-spacing: 1px; }
.recent ul { margin: 0; padding: 0; list-style: none; font-size: 13.5px; }
.recent li { padding: 4px 0; display: flex; justify-content: space-between; gap: 16px; }
.recent .when { color: var(--muted); font-family: var(--mono); font-size: 12px; }

.site-footer { border-top: 1px solid var(--border); margin-top: 60px; padding: 24px 0 40px; color: var(--muted); font-size: 13px; }