/* T.01 grade calculator — lab-notebook dark theme, pairs with main site. */
:root, [data-theme="dark"] {
    --bg: #0b0d0c; --surface: #131716; --surface2: #191f1d;
    --line: #26302b; --line-soft: #1c2320;
    --ink: #e9eee6; --muted: #a9b4a9; --faint: #6e7a71;
    --lime: #c8f04b; --lime-ink: #1a2005; --amber: #ffa14a; --red: #ff6f6f;
    --serif: "Newsreader", Georgia, serif;
    --mono: "JetBrains Mono", ui-monospace, Menlo, Consolas, monospace;
    --sans: system-ui, -apple-system, "Segoe UI", Arial, sans-serif;
}
* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: var(--sans); background: var(--bg); color: var(--ink); line-height: 1.6; font-size: 16px; -webkit-font-smoothing: antialiased; }
.wrap { max-width: 1080px; margin: auto; padding: 0 28px; }
.skip-link { position: absolute; left: -9999px; top: 0; background: var(--lime); color: var(--lime-ink); padding: 10px 16px; border-radius: 0 0 8px 0; z-index: 50; font-family: var(--mono); font-size: 0.85rem; }
.skip-link:focus { left: 0; }

.topbar { border-bottom: 1px solid var(--line); padding: 14px 0; }
.topbar-inner { display: flex; justify-content: space-between; align-items: center; }
.back { font-family: var(--mono); font-size: 0.85rem; text-decoration: none; color: var(--muted); }
.back:hover { color: var(--lime); }
.tool-tag { font-family: var(--mono); font-size: 0.75rem; color: var(--faint); text-transform: uppercase; letter-spacing: 0.1em; }

.head { display: flex; justify-content: space-between; align-items: flex-end; gap: 20px; padding: 40px 0 26px; flex-wrap: wrap; }
h1 { font-family: var(--serif); font-size: clamp(2.2rem, 5vw, 3.2rem); letter-spacing: -0.02em; line-height: 1.05; }
h1 em { font-style: italic; color: var(--lime); }
.sub { color: var(--muted); max-width: 62ch; margin-top: 8px; }
h2 { font-family: var(--mono); font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.14em; color: var(--faint); margin: 22px 0 12px; }

.kbd { font-family: var(--mono); font-size: 0.72rem; border: 1px solid var(--line); border-bottom-width: 2px; border-radius: 6px; padding: 1px 8px; background: var(--surface); color: var(--muted); }
.kbd-in-btn { border-color: rgba(0,0,0,0.25); background: rgba(255,255,255,0.25); color: inherit; }

.switch { display: inline-flex; align-items: center; gap: 10px; font-family: var(--mono); font-size: 0.82rem; color: var(--muted); cursor: pointer; }
.switch input { width: 20px; height: 20px; accent-color: var(--lime); }

.grid { display: grid; grid-template-columns: 1fr 1fr; gap: 22px; padding-bottom: 30px; }
.panel { background: var(--surface); border: 1px solid var(--line); border-radius: 14px; padding: 26px; }
.panel.current { border-top: 3px solid var(--lime); }

.total-label { font-family: var(--mono); font-size: 0.72rem; text-transform: uppercase; letter-spacing: 0.14em; color: var(--faint); }
.total { font-family: var(--serif); font-size: 4.6rem; font-weight: 700; line-height: 1.1; letter-spacing: -0.02em; }
.total-bar { height: 8px; border-radius: 999px; background: var(--surface2); border: 1px solid var(--line); overflow: hidden; margin: 6px 0 4px; }
.total-bar div { height: 100%; width: 0%; background: var(--lime); transition: width 0.2s ease; }
.scale-hint { font-family: var(--mono); font-size: 0.78rem; color: var(--faint); margin-bottom: 16px; }

.row { display: flex; gap: 10px; margin-bottom: 10px; flex-wrap: wrap; align-items: center; }
.btn { font-family: var(--mono); font-size: 0.85rem; padding: 11px 18px; border-radius: 9px; border: 1px solid var(--line); background: transparent; color: var(--ink); cursor: pointer; display: inline-flex; align-items: center; gap: 8px; }
.btn:hover { border-color: var(--lime); color: var(--lime); }
.btn.solid { background: var(--lime); border-color: var(--lime); color: var(--lime-ink); font-weight: 700; }
.btn.solid:hover { color: var(--lime-ink); box-shadow: 3px 3px 0 var(--amber); }
.btn.ghost { width: 100%; justify-content: center; border-style: dashed; color: var(--muted); }
.btn.sm { padding: 8px 14px; font-size: 0.78rem; }
.btn.danger:hover { border-color: var(--red); color: var(--red); }

input[type="number"], input[type="text"] { font-family: var(--mono); font-size: 0.95rem; background: var(--bg); border: 1px solid var(--line); border-radius: 8px; color: var(--ink); padding: 10px 12px; }
input:focus { outline: 2px solid var(--lime); outline-offset: 1px; }
#custom-amount, #scale { width: 90px; }
.scale { font-family: var(--mono); font-size: 0.8rem; color: var(--muted); display: inline-flex; gap: 8px; align-items: center; }

.denom { display: grid; grid-template-columns: 1fr 76px 52px auto auto; gap: 8px; align-items: center; margin-bottom: 8px; }
.denom .d-label { min-width: 0; }
.denom .d-val { width: 76px; }
.denom .d-key { width: 52px; text-align: center; text-transform: lowercase; }
.key-chip { font-family: var(--mono); font-size: 0.72rem; }
.icon-btn { background: var(--bg); border: 1px solid var(--line); color: var(--muted); border-radius: 8px; width: 38px; height: 40px; cursor: pointer; font-size: 0.9rem; }
.icon-btn:hover { border-color: var(--lime); color: var(--lime); }
.icon-btn.del:hover { border-color: var(--red); color: var(--red); }

.record-head { display: flex; justify-content: space-between; align-items: center; }
.record-head h2 { margin: 0; }
.count-pill { display: inline-block; min-width: 30px; text-align: center; background: var(--lime); color: var(--lime-ink); border-radius: 999px; font-size: 0.75rem; padding: 1px 9px; margin-left: 8px; }
.record-actions { display: flex; gap: 8px; }

.entries { list-style: none; max-height: 300px; overflow-y: auto; border: 1px solid var(--line); border-radius: 10px; margin-top: 14px; background: var(--bg); }
.entries li { display: flex; justify-content: space-between; align-items: center; padding: 9px 14px; font-family: var(--mono); font-size: 0.9rem; }
.entries li + li { border-top: 1px solid var(--line-soft); }
.entries li .idx { color: var(--faint); font-size: 0.72rem; margin-right: 10px; }
.entries li .val { color: var(--lime); font-weight: 700; }
.entries li button { background: none; border: none; color: var(--faint); cursor: pointer; font-size: 0.85rem; padding: 2px 6px; }
.entries li button:hover { color: var(--red); }
.empty { color: var(--faint); font-size: 0.9rem; padding: 16px 4px; }

.stats { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; }
.stats div { background: var(--bg); border: 1px solid var(--line); border-radius: 10px; padding: 10px 14px; display: grid; }
.stats span { font-family: var(--mono); font-size: 0.68rem; text-transform: uppercase; letter-spacing: 0.1em; color: var(--faint); }
.stats strong { font-family: var(--serif); font-size: 1.4rem; color: var(--ink); }
.hint { font-size: 0.82rem; color: var(--faint); margin-top: 10px; }

.foot { padding: 18px 28px 40px; font-family: var(--mono); font-size: 0.75rem; color: var(--faint); }

@media (max-width: 860px) {
    .grid { grid-template-columns: 1fr; }
    .denom { grid-template-columns: 1fr 70px 48px auto auto; }
    .stats { grid-template-columns: repeat(2, 1fr); }
}
@media (prefers-reduced-motion: reduce) { .total-bar div { transition: none; } }