/* Calcora — "precision instrument" layout: input console on the left, live readout on the right,
   reference material below. Dark-first, with a full light palette. */
:root {
  --bg: #090d16;
  --bg-2: #0e1422;
  --panel: rgba(20, 28, 46, 0.72);
  --panel-solid: #121a2b;
  --line: rgba(148, 176, 220, 0.14);
  --line-strong: rgba(148, 176, 220, 0.28);
  --fg: #e6ecf7;
  --muted: #93a1ba;
  --faint: #5f6d86;
  --ion: #6fe3ff;
  --ion-ink: #04202b;
  --ion-soft: rgba(111, 227, 255, 0.12);
  --flare: #ffb26b;
  --good: #5ee6a8;
  --warn: #ffcb6b;
  --bad: #ff7a8a;
  --glow-a: rgba(64, 140, 255, 0.22);
  --glow-b: rgba(111, 227, 255, 0.14);
  --dot: rgba(148, 176, 220, 0.09);
  --shadow: 0 24px 60px -24px rgba(0, 0, 0, 0.7);
  --display: "Sora", "Avenir Next", "Segoe UI", system-ui, sans-serif;
  --body: "Instrument Sans", "Segoe UI", system-ui, -apple-system, sans-serif;
  --mono: "JetBrains Mono", ui-monospace, "SFMono-Regular", Menlo, Consolas, monospace;
  --radius: 14px;
  --radius-sm: 9px;
  color-scheme: dark;
}
@media (prefers-color-scheme: light) {
  :root:not([data-theme="dark"]) {
    --bg: #f4f6fb; --bg-2: #eaeef6; --panel: rgba(255, 255, 255, 0.82); --panel-solid: #ffffff;
    --line: rgba(30, 50, 90, 0.12); --line-strong: rgba(30, 50, 90, 0.24);
    --fg: #0d1626; --muted: #4c5a72; --faint: #8592a8;
    --ion: #0577a3; --ion-ink: #ffffff; --ion-soft: rgba(5, 119, 163, 0.09); --flare: #c25e0c;
    --good: #0e8a5a; --warn: #a86a00; --bad: #c4314b;
    --glow-a: rgba(64, 140, 255, 0.14); --glow-b: rgba(5, 170, 220, 0.1); --dot: rgba(30, 50, 90, 0.07);
    --shadow: 0 20px 50px -28px rgba(20, 40, 80, 0.35);
    color-scheme: light;
  }
}
:root[data-theme="light"] {
  --bg: #f4f6fb; --bg-2: #eaeef6; --panel: rgba(255, 255, 255, 0.82); --panel-solid: #ffffff;
  --line: rgba(30, 50, 90, 0.12); --line-strong: rgba(30, 50, 90, 0.24);
  --fg: #0d1626; --muted: #4c5a72; --faint: #8592a8;
  --ion: #0577a3; --ion-ink: #ffffff; --ion-soft: rgba(5, 119, 163, 0.09); --flare: #c25e0c;
  --good: #0e8a5a; --warn: #a86a00; --bad: #c4314b;
  --glow-a: rgba(64, 140, 255, 0.14); --glow-b: rgba(5, 170, 220, 0.1); --dot: rgba(30, 50, 90, 0.07);
  --shadow: 0 20px 50px -28px rgba(20, 40, 80, 0.35);
  color-scheme: light;
}

*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
@media (prefers-reduced-motion: reduce) { html { scroll-behavior: auto; } *, *::before, *::after { animation: none !important; transition: none !important; } }
body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font: 16px/1.65 var(--body);
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  overflow-x: hidden;
}
body::before { content: ""; position: fixed; inset: 0 0 auto; height: env(safe-area-inset-top, 0px); z-index: 60; background: var(--bg); }
.aurora { position: absolute; inset: 0 0 auto; height: 720px; pointer-events: none; z-index: 0; overflow: hidden;
  background:
    radial-gradient(600px 340px at 12% -40px, var(--glow-a), transparent 70%),
    radial-gradient(520px 300px at 88% 40px, var(--glow-b), transparent 70%);
}
.aurora::after { content: ""; position: absolute; inset: 0;
  background-image: radial-gradient(var(--dot) 1px, transparent 1px); background-size: 22px 22px;
  mask-image: linear-gradient(to bottom, #000 30%, transparent); -webkit-mask-image: linear-gradient(to bottom, #000 30%, transparent); }
img, svg { max-width: 100%; }
a { color: var(--ion); text-underline-offset: 3px; }
a:hover { text-decoration-thickness: 2px; }
:focus-visible { outline: 2px solid var(--ion); outline-offset: 2px; border-radius: 6px; }
[hidden] { display: none !important; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0 0 0 0); white-space: nowrap; }

.shell { position: relative; z-index: 1; max-width: 1160px; margin: 0 auto;
  padding-left: max(20px, env(safe-area-inset-left, 0px)); padding-right: max(20px, env(safe-area-inset-right, 0px)); }

/* Header */
.site-header { position: sticky; top: env(safe-area-inset-top, 0px); z-index: 50;
  background: color-mix(in srgb, var(--bg) 78%, transparent); backdrop-filter: blur(14px); -webkit-backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--line); }
.site-header .shell { display: flex; align-items: center; gap: 20px; min-height: 64px; }
.brand { display: inline-flex; align-items: center; gap: 10px; color: var(--fg); text-decoration: none; font: 600 18px/1 var(--display); letter-spacing: -0.01em; }
.brand-mark { width: 28px; height: 28px; flex: none; }
.nav { display: flex; gap: 4px; margin-left: auto; flex-wrap: wrap; }
.nav a { color: var(--muted); text-decoration: none; font-size: 14.5px; font-weight: 500; padding: 8px 12px; border-radius: 8px; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--fg); background: var(--ion-soft); }
.theme-toggle { flex: none; width: 38px; height: 38px; border-radius: 10px; border: 1px solid var(--line-strong); background: transparent; color: var(--fg); cursor: pointer; display: grid; place-items: center; }
.theme-toggle:hover { border-color: var(--ion); }
.theme-toggle svg { width: 18px; height: 18px; }
.menu-btn { display: none; }
@media (max-width: 820px) {
  .nav { display: none; position: absolute; top: 64px; left: 0; right: 0; flex-direction: column; gap: 2px; padding: 10px max(20px, env(safe-area-inset-right, 0px)) 16px max(20px, env(safe-area-inset-left, 0px));
    background: var(--panel-solid); border-bottom: 1px solid var(--line); }
  .nav.open { display: flex; }
  .nav a { padding: 12px; font-size: 16px; }
  .menu-btn { display: grid; margin-left: auto; }
}

/* Type */
h1, h2, h3 { font-family: var(--display); letter-spacing: -0.02em; text-wrap: balance; line-height: 1.15; margin: 0; }
h1 { font-size: clamp(30px, 5vw, 48px); font-weight: 600; }
h2 { font-size: clamp(23px, 3vw, 30px); font-weight: 600; }
h3 { font-size: 18px; font-weight: 600; letter-spacing: -0.01em; }
.eyebrow { font: 500 12px/1 var(--mono); letter-spacing: 0.14em; text-transform: uppercase; color: var(--ion); display: inline-flex; align-items: center; gap: 8px; }
.eyebrow::before { content: ""; width: 18px; height: 1px; background: currentColor; }
.lede { color: var(--muted); font-size: 18px; max-width: 62ch; margin: 0; }

/* Breadcrumb */
.crumbs { display: flex; flex-wrap: wrap; gap: 6px; list-style: none; padding: 0; margin: 0 0 18px; font-size: 13.5px; color: var(--faint); }
.crumbs a { color: var(--muted); text-decoration: none; }
.crumbs a:hover { color: var(--fg); }
.crumbs li + li::before { content: "/"; margin-right: 6px; color: var(--faint); }

/* Tool hero */
.tool-hero { padding-block: 40px 28px; display: grid; gap: 14px; }

/* Workspace */
.workspace { display: grid; grid-template-columns: minmax(0, 1.2fr) minmax(0, 0.8fr); gap: 20px; align-items: start; padding-bottom: 56px; }
@media (max-width: 900px) { .workspace { grid-template-columns: minmax(0, 1fr); } }
.console, .readout { background: var(--panel); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow);
  backdrop-filter: blur(10px); -webkit-backdrop-filter: blur(10px); }
.console { padding: 24px; display: grid; gap: 20px; min-width: 0; }
.readout { padding: 24px; position: sticky; top: calc(env(safe-area-inset-top, 0px) + 84px); display: grid; gap: 18px; min-width: 0; overflow: hidden; }
.readout::before { content: ""; position: absolute; inset: 0 0 auto; height: 2px; background: linear-gradient(90deg, transparent, var(--ion), transparent); opacity: .8; }
@media (max-width: 900px) { .readout { position: relative; top: 0; } }
.panel-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.panel-title { font: 500 12px/1 var(--mono); letter-spacing: 0.14em; text-transform: uppercase; color: var(--muted); }

/* Fields */
.fields { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); }
.field { display: grid; gap: 7px; min-width: 0; align-content: start; }
.field label, .label { font-size: 13.5px; font-weight: 600; color: var(--fg); }
.hint { font-size: 12.5px; color: var(--faint); line-height: 1.45; }
input, select { font: 500 16px/1.2 var(--body); color: var(--fg); background: var(--bg-2); border: 1px solid var(--line-strong);
  border-radius: var(--radius-sm); padding: 11px 12px; width: 100%; min-width: 0; transition: border-color .15s, box-shadow .15s; }
input[type="number"] { font-family: var(--mono); font-variant-numeric: tabular-nums; }
input:hover, select:hover { border-color: var(--faint); }
input:focus, select:focus { outline: none; border-color: var(--ion); box-shadow: 0 0 0 3px var(--ion-soft); }
.suffix-wrap { position: relative; }
.suffix-wrap input { padding-right: 34px; }
.suffix-wrap span { position: absolute; right: 12px; top: 50%; transform: translateY(-50%); color: var(--faint); font: 500 14px var(--mono); pointer-events: none; }
.check { display: flex; align-items: center; gap: 10px; font-size: 14.5px; color: var(--fg); cursor: pointer; }
.check input { width: 18px; height: 18px; accent-color: var(--ion); padding: 0; }

/* Segmented control */
.segmented { display: inline-flex; padding: 4px; border-radius: 11px; background: var(--bg-2); border: 1px solid var(--line); gap: 4px; flex-wrap: wrap; }
.segmented button { font: 600 14px/1 var(--body); color: var(--muted); background: transparent; border: 0; padding: 9px 14px; border-radius: 8px; cursor: pointer; }
.segmented button[aria-pressed="true"] { background: var(--ion); color: var(--ion-ink); }

/* Row editor (weighted grade, GPA) */
.rows { display: grid; gap: 8px; }
.row-head, .row { display: grid; gap: 8px; align-items: center; grid-template-columns: var(--cols); }
.row-head { font: 500 11.5px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--faint); padding: 0 2px; }
.row input, .row select { padding: 10px; font-size: 15px; }
.icon-btn { width: 40px; height: 40px; border-radius: 9px; border: 1px solid var(--line); background: transparent; color: var(--faint); cursor: pointer; display: grid; place-items: center; }
.icon-btn:hover { color: var(--bad); border-color: var(--bad); }
.icon-btn svg { width: 16px; height: 16px; }
@media (max-width: 560px) {
  .row-head { display: none; }
  .row { grid-template-columns: 1fr 1fr 40px; padding: 10px; border: 1px solid var(--line); border-radius: 11px; }
  .row > :first-child { grid-column: 1 / -1; }
  .row.gpa-row { grid-template-columns: 1fr 1fr; }
  .row.gpa-row > :last-child { grid-column: 1 / -1; width: 100%; }
}
.btn-row { display: flex; gap: 10px; flex-wrap: wrap; }
.btn { font: 600 14.5px/1 var(--body); border-radius: 10px; padding: 12px 16px; cursor: pointer; border: 1px solid var(--line-strong); background: transparent; color: var(--fg); display: inline-flex; align-items: center; gap: 8px; text-decoration: none; }
.btn:hover { border-color: var(--ion); color: var(--ion); }
.btn.primary { background: var(--ion); color: var(--ion-ink); border-color: var(--ion); }
.btn.primary:hover { filter: brightness(1.08); color: var(--ion-ink); }
.btn svg { width: 16px; height: 16px; }

/* Readout */
.big { display: grid; gap: 6px; }
.big-label { font-size: 13.5px; color: var(--muted); }
.big-value { font: 500 clamp(44px, 7vw, 64px)/1 var(--mono); font-variant-numeric: tabular-nums; letter-spacing: -0.04em; color: var(--fg); display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; }
.big-value small { font-size: 0.38em; color: var(--muted); letter-spacing: 0; }
.chip { font: 600 13px/1 var(--mono); padding: 6px 10px; border-radius: 999px; border: 1px solid currentColor; letter-spacing: .02em; display: inline-flex; align-items: center; gap: 6px; }
.chip.good { color: var(--good); } .chip.warn { color: var(--warn); } .chip.bad { color: var(--bad); } .chip.info { color: var(--ion); }
.note { font-size: 14px; color: var(--muted); margin: 0; line-height: 1.55; }
.note strong { color: var(--fg); }
.stats { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 1px; background: var(--line); border: 1px solid var(--line); border-radius: 11px; overflow: hidden; }
.stat { background: var(--panel-solid); padding: 12px 14px; display: grid; gap: 4px; min-width: 0; }
.stat span { font-size: 12.5px; color: var(--faint); }
.stat b a { font: 600 14px/1.2 var(--body); }
.stat b { font: 600 18px/1.2 var(--mono); font-variant-numeric: tabular-nums; color: var(--fg); overflow-wrap: anywhere; }

/* Grade scale band — shows where a percentage lands on the US letter scale */
.scale { display: grid; gap: 8px; }
.scale-bar { position: relative; height: 10px; border-radius: 99px; display: grid; grid-template-columns: 60fr 10fr 10fr 10fr 10fr; gap: 2px; }
.scale-bar i { display: block; border-radius: 2px; background: var(--line-strong); }
.scale-bar i:first-child { border-radius: 99px 2px 2px 99px; } .scale-bar i:last-child { border-radius: 2px 99px 99px 2px; }
.scale-bar i.on { background: var(--ion); }
.scale-marker { position: absolute; top: -5px; width: 3px; height: 20px; border-radius: 2px; background: var(--fg); transform: translateX(-50%); transition: left .35s cubic-bezier(.2,.8,.2,1); box-shadow: 0 0 0 3px var(--bg); }
.scale-labels { display: grid; grid-template-columns: 60fr 10fr 10fr 10fr 10fr; font: 500 11px/1 var(--mono); color: var(--faint); }
.scale-labels span { text-align: center; } .scale-labels span:first-child { text-align: left; }

/* Target table in readout */
.mini-table { width: 100%; border-collapse: collapse; font-size: 14px; }
.mini-table th { text-align: left; font: 500 11.5px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--faint); padding: 0 0 8px; }
.mini-table td { padding: 8px 0; border-top: 1px solid var(--line); font-variant-numeric: tabular-nums; }
.mini-table td:last-child, .mini-table th:last-child { text-align: right; font-family: var(--mono); }

/* Timeline (date tools) */
.timeline { position: relative; height: 44px; }
.timeline::before { content: ""; position: absolute; left: 6px; right: 6px; top: 13px; height: 2px; background: linear-gradient(90deg, var(--ion), var(--flare)); border-radius: 2px; }
.timeline .dot { position: absolute; top: 7px; width: 14px; height: 14px; border-radius: 50%; background: var(--bg); border: 2px solid var(--ion); }
.timeline .dot.end { right: 0; border-color: var(--flare); } .timeline .dot.start { left: 0; }
.timeline .t { position: absolute; top: 28px; font: 500 11.5px/1 var(--mono); color: var(--muted); white-space: nowrap; }
.timeline .t.start { left: 0; } .timeline .t.end { right: 0; }

/* Article */
.article { display: grid; grid-template-columns: minmax(0, 1fr) 260px; gap: 48px; padding-block: 24px 64px; border-top: 1px solid var(--line); }
@media (max-width: 900px) { .article { grid-template-columns: minmax(0, 1fr); gap: 24px; } }
.prose { max-width: 70ch; min-width: 0; display: grid; gap: 16px; }
.prose h2 { margin-top: 28px; scroll-margin-top: 90px; }
.prose h3 { margin-top: 10px; }
.prose p, .prose ul, .prose ol { margin: 0; color: var(--fg); }
.prose p { color: color-mix(in srgb, var(--fg) 88%, var(--muted)); }
.prose ul, .prose ol { padding-left: 22px; display: grid; gap: 6px; }
.prose li::marker { color: var(--ion); }
.formula { font: 500 15px/1.6 var(--mono); background: var(--bg-2); border: 1px solid var(--line); border-left: 2px solid var(--ion); border-radius: 0 10px 10px 0; padding: 14px 16px; overflow-x: auto; white-space: pre; color: var(--fg); }
.table-wrap { overflow-x: auto; border: 1px solid var(--line); border-radius: 12px; }
.table-wrap table { width: 100%; border-collapse: collapse; font-size: 14.5px; min-width: 420px; }
.table-wrap th, .table-wrap td { padding: 10px 14px; text-align: left; border-bottom: 1px solid var(--line); font-variant-numeric: tabular-nums; }
.table-wrap th { font: 500 12px/1.2 var(--mono); letter-spacing: .08em; text-transform: uppercase; color: var(--muted); background: var(--bg-2); }
.table-wrap tr:last-child td { border-bottom: 0; }
.example { background: var(--ion-soft); border: 1px solid var(--line); border-radius: 12px; padding: 16px 18px; display: grid; gap: 8px; }
.example p { margin: 0; }
.toc { position: sticky; top: calc(env(safe-area-inset-top, 0px) + 90px); display: grid; gap: 4px; align-content: start; font-size: 14px; }
.toc .panel-title { margin-bottom: 10px; }
.toc a { color: var(--muted); text-decoration: none; padding: 5px 0 5px 12px; border-left: 1px solid var(--line); }
.toc a:hover { color: var(--fg); border-color: var(--ion); }
@media (max-width: 900px) { .toc { display: none; } }

/* FAQ */
.faq { display: grid; gap: 10px; }
.faq details { border: 1px solid var(--line); border-radius: 12px; background: var(--panel); }
.faq summary { cursor: pointer; padding: 15px 18px; font-weight: 600; list-style: none; display: flex; justify-content: space-between; gap: 16px; }
.faq summary::-webkit-details-marker { display: none; }
.faq summary::after { content: "+"; font: 400 20px/1 var(--mono); color: var(--ion); flex: none; transition: transform .2s; }
.faq details[open] summary::after { transform: rotate(45deg); }
.faq details > div { padding: 0 18px 16px; color: var(--muted); }
.faq details > div p { margin: 0; }

/* Tool cards */
.cards { display: grid; gap: 14px; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); }
.card { position: relative; display: grid; gap: 10px; align-content: start; padding: 20px; border-radius: var(--radius); border: 1px solid var(--line); background: var(--panel);
  text-decoration: none; color: var(--fg); transition: border-color .2s, transform .2s; min-width: 0; }
.card:hover { border-color: var(--ion); transform: translateY(-2px); }
.card .card-icon { width: 40px; height: 40px; border-radius: 10px; display: grid; place-items: center; background: var(--ion-soft); color: var(--ion); }
.card .card-icon svg { width: 20px; height: 20px; }
.card p { margin: 0; color: var(--muted); font-size: 14.5px; line-height: 1.55; }
.card .go { font: 500 12px/1 var(--mono); letter-spacing: .1em; text-transform: uppercase; color: var(--ion); margin-top: 4px; }
.related { padding-block: 8px 72px; display: grid; gap: 18px; }

/* Home */
.home-hero { padding-block: 64px 48px; display: grid; grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr); gap: 40px; align-items: center; }
@media (max-width: 900px) { .home-hero { grid-template-columns: minmax(0, 1fr); padding-block: 40px 32px; } }
.home-hero h1 { font-size: clamp(36px, 6vw, 64px); font-weight: 600; letter-spacing: -0.035em; }
.home-hero h1 em { font-style: normal; color: var(--ion); }
.home-hero .copy { display: grid; gap: 20px; }
.quick { padding: 22px; }
.section { padding-block: 40px; display: grid; gap: 22px; }
.section-head { display: grid; gap: 10px; }
.group-title { font: 500 12px/1 var(--mono); letter-spacing: .14em; text-transform: uppercase; color: var(--muted); display: flex; align-items: center; gap: 12px; }
.group-title::after { content: ""; flex: 1; height: 1px; background: var(--line); }
.points { display: grid; gap: 14px; grid-template-columns: repeat(auto-fit, minmax(230px, 1fr)); }
.point { padding: 18px 0; border-top: 1px solid var(--line-strong); display: grid; gap: 6px; }
.point p { margin: 0; color: var(--muted); font-size: 15px; }

.groups { display: grid; gap: 24px; grid-template-columns: repeat(auto-fit, minmax(290px, 1fr)); }
.groups .cards { grid-template-columns: minmax(0, 1fr); }
.groups > div, .point, .card { align-content: start; }

/* Footer */
.site-footer { border-top: 1px solid var(--line); padding-block: 40px; color: var(--muted); font-size: 14px; position: relative; z-index: 1; }
.footer-grid { display: grid; grid-template-columns: 1.4fr repeat(3, 1fr); gap: 28px; }
@media (max-width: 760px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
.footer-grid h3 { font: 500 12px/1 var(--mono); letter-spacing: .12em; text-transform: uppercase; color: var(--faint); margin-bottom: 12px; }
.footer-grid ul { list-style: none; padding: 0; margin: 0; display: grid; gap: 8px; }
.footer-grid a { color: var(--muted); text-decoration: none; }
.footer-grid a:hover { color: var(--fg); }
.footer-base { margin-top: 32px; padding-top: 20px; border-top: 1px solid var(--line); display: flex; justify-content: space-between; gap: 12px; flex-wrap: wrap; color: var(--faint); font-size: 13px; }

/* Plain pages */
.page { padding-block: 48px 72px; display: grid; gap: 18px; }

/* Value pulse when a result changes */
@keyframes pulse { from { color: var(--ion); } to { color: var(--fg); } }
.pulse { animation: pulse .6s ease-out; }