/* AI Cost Calculator — same design language as akhilrajs.com. Colours are tokens only. */

:root {
    --bg: #f6f3ec;
    --bg-sunk: #eeeae0;
    --surface: #fbf9f4;
    --ink: #1c1b18;
    --ink-2: #4b4840;
    --muted: #6f6b62;
    --rule: #dcd6c9;
    --rule-strong: #c4bdac;
    --accent: #a8441e;
    --accent-soft: #f0e0d4;
    --good: #2f7a55;
    --good-soft: #dcefe4;
    --seg-input: #a8441e;
    --seg-cached: #e3b49c;
    --seg-output: #1c1b18;
    --line-api: #a8441e;
    --line-self: #2f6f9e;
    --on-ink: #f6f3ec;
    --font-display: 'Fraunces', Georgia, serif;
    --font-body: 'Inter', system-ui, -apple-system, 'Segoe UI', sans-serif;
    --radius: 14px;
    color-scheme: light;
}

@media (prefers-color-scheme: dark) {
    :root {
        --bg: #12110f;
        --bg-sunk: #1a1916;
        --surface: #1d1c19;
        --ink: #eeeae1;
        --ink-2: #c3bdb0;
        --muted: #9a9488;
        --rule: #2f2d28;
        --rule-strong: #46423a;
        --accent: #e58a62;
        --accent-soft: #3a2419;
        --good: #6fcb9a;
        --good-soft: #17301f;
        --seg-input: #e58a62;
        --seg-cached: #7a4a33;
        --seg-output: #eeeae1;
        --line-api: #e58a62;
        --line-self: #7fb8e0;
        --on-ink: #12110f;
        color-scheme: dark;
    }
}

*, *::before, *::after { box-sizing: border-box; }
* { margin: 0; padding: 0; }

body {
    background: var(--bg);
    color: var(--ink);
    font: 400 16px/1.6 var(--font-body);
    -webkit-font-smoothing: antialiased;
}

a { color: inherit; text-decoration-color: color-mix(in srgb, var(--accent) 80%, transparent); text-decoration-thickness: 1.5px; text-underline-offset: 3px; }
a:hover { color: var(--accent); }
:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; border-radius: 4px; }

h1, h2, h3 { font-family: var(--font-display); font-weight: 400; letter-spacing: -0.015em; line-height: 1.15; }

.wrap { max-width: 1200px; margin: 0 auto; padding: 0 clamp(16px, 4vw, 40px); }

/* Header */
.topbar { border-bottom: 1px solid var(--rule); }
.topbar .wrap { display: flex; justify-content: space-between; align-items: center; height: 60px; gap: 16px; }
.brand { font-family: var(--font-display); font-size: 1.15rem; text-decoration: none; }
.brand span { color: var(--accent); }
.topbar nav { display: flex; gap: 18px; font-size: 0.9rem; color: var(--ink-2); }
.topbar nav a { text-decoration: none; }

.hero { padding: clamp(36px, 6vw, 64px) 0 24px; }
.hero h1 { font-size: clamp(2.1rem, 5vw, 3.4rem); max-width: 18ch; margin-bottom: 14px; }
.hero h1 em { color: var(--accent); }
.hero p { color: var(--ink-2); max-width: 46em; font-size: 1.08rem; }
.asof {
    display: inline-flex; align-items: center; gap: 8px; margin-top: 18px;
    font-size: 0.82rem; font-weight: 600; color: var(--good);
    background: var(--good-soft); padding: 5px 12px; border-radius: 999px;
}

/* Tabs */
.tabs { display: flex; gap: 4px; border-bottom: 1px solid var(--rule); margin-top: 8px; overflow-x: auto; }
.tab {
    font: 500 0.95rem var(--font-body); color: var(--ink-2); background: none; border: 0;
    padding: 12px 16px; border-bottom: 2px solid transparent; cursor: pointer; white-space: nowrap;
}
.tab[aria-selected='true'] { color: var(--ink); border-bottom-color: var(--accent); }
.tab:hover { color: var(--ink); }
.panel { padding: 28px 0 56px; }
.panel[hidden] { display: none; }

/* Layout */
.layout { display: grid; grid-template-columns: minmax(280px, 340px) minmax(0, 1fr); gap: clamp(24px, 4vw, 48px); align-items: start; }
.inputs {
    position: sticky; top: 16px; background: var(--surface); border: 1px solid var(--rule);
    border-radius: var(--radius); padding: 20px;
}
.inputs h2 { font-size: 1.3rem; margin-bottom: 4px; }
.inputs .hint { font-size: 0.85rem; color: var(--muted); margin-bottom: 16px; }

.field { margin-bottom: 14px; }
.field label, .field .label { display: flex; justify-content: space-between; gap: 8px; font-size: 0.85rem; font-weight: 500; color: var(--ink-2); margin-bottom: 6px; }
.field output { font-variant-numeric: tabular-nums; color: var(--ink); font-weight: 600; }
.field small { display: block; font-size: 0.78rem; color: var(--muted); margin-top: 4px; }
input[type='number'], select {
    width: 100%; font: 400 0.95rem var(--font-body); color: var(--ink); background: var(--bg);
    border: 1px solid var(--rule-strong); border-radius: 9px; padding: 9px 11px;
}
input[type='range'] { width: 100%; accent-color: var(--accent); }
.row2 { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; }

.chips { display: flex; flex-wrap: wrap; gap: 6px; margin-bottom: 16px; }
.chip {
    font: 500 0.8rem var(--font-body); color: var(--ink-2); background: var(--bg);
    border: 1px solid var(--rule-strong); border-radius: 999px; padding: 6px 11px; cursor: pointer;
}
.chip:hover { border-color: var(--ink); color: var(--ink); }
.chip[aria-pressed='true'] { background: var(--ink); color: var(--on-ink); border-color: var(--ink); }

.checks { display: flex; flex-wrap: wrap; gap: 6px 14px; font-size: 0.85rem; color: var(--ink-2); }
.checks label { display: inline-flex; gap: 6px; align-items: center; font-weight: 400; margin: 0; }
.checks input { accent-color: var(--accent); }

/* Results */
.cards { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 12px; margin-bottom: 22px; }
.card { background: var(--surface); border: 1px solid var(--rule); border-radius: 12px; padding: 14px 16px; }
.card .k { font-size: 0.78rem; color: var(--muted); text-transform: uppercase; letter-spacing: 0.08em; font-weight: 600; }
.card .v { font-family: var(--font-display); font-size: 1.7rem; line-height: 1.15; margin: 4px 0 2px; font-variant-numeric: tabular-nums; }
.card .s { font-size: 0.85rem; color: var(--ink-2); }
.card.win { border-color: var(--good); }
.card.win .v { color: var(--good); }

.insight {
    font-family: var(--font-display); font-size: 1.25rem; line-height: 1.4; margin-bottom: 22px;
    padding-left: 14px; border-left: 3px solid var(--accent);
}

.table-wrap { overflow-x: auto; border: 1px solid var(--rule); border-radius: 12px; background: var(--surface); }
table { width: 100%; border-collapse: collapse; font-size: 0.9rem; font-variant-numeric: tabular-nums; }
th, td { text-align: right; padding: 10px 10px; border-bottom: 1px solid var(--rule); white-space: nowrap; }
th { font-size: 0.75rem; text-transform: uppercase; letter-spacing: 0.06em; color: var(--muted); font-weight: 600; background: var(--bg-sunk); }
th:first-child, td:first-child, th.l, td.l { text-align: left; }
tbody tr:last-child td { border-bottom: 0; }
tbody tr.best td { background: var(--good-soft); }
td .prov { display: block; font-size: 0.75rem; color: var(--muted); }
td .flag { display: inline-block; margin-left: 6px; font-size: 0.7rem; color: var(--accent); font-weight: 600; }
.bar { display: flex; height: 10px; border-radius: 3px; overflow: hidden; background: var(--bg-sunk); width: 96px; }
.bar span { display: block; height: 100%; }
.legend { display: flex; flex-wrap: wrap; gap: 14px; font-size: 0.8rem; color: var(--ink-2); margin: 10px 2px 0; }
.legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; margin-right: 6px; vertical-align: -1px; }

.notes { margin-top: 18px; font-size: 0.85rem; color: var(--ink-2); display: grid; gap: 6px; }

.chart { background: var(--surface); border: 1px solid var(--rule); border-radius: 12px; padding: 14px; margin-bottom: 22px; }
.chart h3 { font-size: 1.1rem; margin-bottom: 8px; }
.chart svg { width: 100%; height: auto; display: block; }
.chart .axis { stroke: var(--rule-strong); stroke-width: 1; }
.chart .grid { stroke: var(--rule); stroke-width: 1; }
.chart text { fill: var(--muted); font: 11px var(--font-body); }
.chart .api { fill: none; stroke: var(--line-api); stroke-width: 2.5; }
.chart .self { fill: none; stroke: var(--line-self); stroke-width: 2.5; }
.chart .now { stroke: var(--ink-2); stroke-dasharray: 4 4; }
.chart .dot { fill: var(--good); }

.split { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; }
.box { background: var(--surface); border: 1px solid var(--rule); border-radius: var(--radius); padding: 20px; }
.box h2 { font-size: 1.4rem; margin-bottom: 6px; }
.box > p { color: var(--ink-2); font-size: 0.92rem; margin-bottom: 16px; }

.method { max-width: 760px; }
.method h2 { font-size: 1.6rem; margin: 28px 0 10px; }
.method h2:first-child { margin-top: 0; }
.method p, .method li { color: var(--ink-2); margin-bottom: 10px; }
.method ul { padding-left: 20px; }
.method code, .formula {
    font: 0.88rem ui-monospace, SFMono-Regular, Menlo, monospace; background: var(--bg-sunk);
    border-radius: 6px; padding: 1px 6px; color: var(--ink);
}
.formula { display: block; padding: 10px 12px; margin: 6px 0 12px; overflow-x: auto; }

.btn {
    display: inline-flex; align-items: center; gap: 8px; font: 500 0.9rem var(--font-body);
    padding: 9px 16px; border-radius: 999px; border: 1px solid var(--rule-strong);
    background: transparent; color: var(--ink); cursor: pointer;
}
.btn:hover { border-color: var(--ink); }
.toolbar { display: flex; flex-wrap: wrap; gap: 10px; align-items: center; margin-bottom: 18px; }
.toast { font-size: 0.85rem; color: var(--good); }

footer { border-top: 1px solid var(--rule); padding: 24px 0 40px; font-size: 0.85rem; color: var(--muted); }
footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 10px; }

@media (max-width: 900px) {
    .layout, .split { grid-template-columns: minmax(0, 1fr); }
    .inputs { position: static; }
}
@media (max-width: 560px) {
    .topbar nav a.hide-sm { display: none; }
    th.opt, td.opt { display: none; }
    .cards { grid-template-columns: repeat(2, minmax(0, 1fr)); }
    .card .v { font-size: 1.35rem; }
}
@media (prefers-reduced-motion: reduce) { * { transition: none !important; } }