:root {
    color-scheme: dark;
    --ink: #f4f2eb;
    --muted: #a4a9b2;
    --surface: #191c22;
    --surface-2: #20242c;
    --line: #343a45;
    --mint: #91f2ce;
    --amber: #ffc66d;
    --violet: #a99cff;
    --danger: #ff9f9f;
    font-family: "Segoe UI Variable", "Aptos", system-ui, sans-serif;
    background: #111318;
    color: var(--ink);
}

* { box-sizing: border-box; }
body { margin: 0; min-width: 320px; background: radial-gradient(circle at 75% 0%, #242033 0, transparent 35rem), #111318; }
button, input, textarea { font: inherit; }
button { cursor: pointer; }

.hero {
    max-width: 1320px;
    margin: 0 auto;
    padding: 72px 36px 52px;
    display: flex;
    align-items: flex-end;
    justify-content: space-between;
    gap: 32px;
}
.hero-copy { max-width: 860px; }
.eyebrow, .kicker { color: var(--mint); text-transform: uppercase; letter-spacing: .16em; font-size: .72rem; font-weight: 800; }
h1 { margin: 10px 0 20px; font-size: clamp(3rem, 7vw, 6.6rem); line-height: .93; letter-spacing: -.065em; }
.lead { max-width: 660px; color: var(--muted); font-size: 1.08rem; line-height: 1.7; }
.hero-mark { display: grid; grid-template-columns: repeat(2, 64px); gap: 8px; font: 500 2rem ui-monospace, "Cascadia Code", monospace; }
.hero-mark span { display: grid; place-items: center; aspect-ratio: 1; border: 1px solid var(--line); background: #171a20cc; }
.hero-mark span:nth-child(3) { color: #111318; background: var(--mint); }

main { max-width: 1320px; margin: 0 auto; padding: 0 36px 64px; }
.share-toolbar { display: grid; grid-template-columns: 1fr auto; gap: 14px 24px; align-items: center; margin-bottom: 18px; padding: 18px 20px; background: #15181e; border: 1px solid var(--line); }
.share-toolbar strong { display: block; margin-top: 5px; font-size: .92rem; }
.toolbar-actions, .panel-actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 8px; }
.secondary-action { border: 1px solid var(--line); color: var(--ink); background: #20242c; padding: 9px 12px; font-size: .76rem; font-weight: 750; }
.link-action { display: inline-flex; align-items: center; justify-content: center; text-decoration: none; }
.secondary-action:hover { color: var(--mint); border-color: #457967; }
.action-status { grid-column: 1 / -1; color: var(--mint); font-size: .75rem; }
.embed-mode { padding-top: 18px; padding-bottom: 18px; }
.embed-mode .tool-grid { grid-template-columns: 1fr; }
.embed-convert .panel:not(.converter-panel),
.embed-fraction .panel:not(.fraction-panel),
.embed-bits .panel:not(.bits-panel),
.embed-constraints .panel:not(.constraints-panel) { display: none; }
.embed-mode .panel { grid-column: auto; box-shadow: none; }
.tool-grid { display: grid; grid-template-columns: minmax(300px, .82fr) minmax(520px, 1.45fr); gap: 18px; align-items: start; }
.panel { background: linear-gradient(145deg, #1c2027, #171a20); border: 1px solid var(--line); padding: 28px; box-shadow: 0 18px 60px #0004; }
.bits-panel, .constraints-panel { grid-column: 1 / -1; }
.panel-heading { display: flex; align-items: flex-start; justify-content: space-between; gap: 16px; margin-bottom: 28px; }
.panel-heading h2 { margin: 4px 0 0; font-size: 1.35rem; letter-spacing: -.025em; }
.panel-heading p { margin: 0; }
.badge { border: 1px solid #6b60b1; color: var(--violet); padding: 6px 9px; font: 500 .68rem ui-monospace, "Cascadia Code", monospace; }
.badge.amber { border-color: #8d6a34; color: var(--amber); }
.badge.mint { border-color: #457967; color: var(--mint); }
label { display: block; margin: 0 0 8px; color: var(--muted); font-size: .76rem; font-weight: 700; text-transform: uppercase; letter-spacing: .08em; }
input, textarea { width: 100%; color: var(--ink); background: #101217; border: 1px solid var(--line); padding: 12px 13px; outline: none; }
input:focus, textarea:focus { border-color: var(--mint); box-shadow: 0 0 0 2px #91f2ce1f; }
.primary-input { font: 500 1.35rem ui-monospace, "Cascadia Code", monospace; padding: 16px; }
.field-row { display: grid; grid-template-columns: 1fr auto 1fr; gap: 12px; align-items: end; margin: 18px 0; }
.swap { color: var(--muted); padding-bottom: 12px; }
.action, .small-action { border: 0; color: #101217; background: var(--mint); font-weight: 800; padding: 13px 18px; }
.action { width: 100%; }
.small-action { white-space: nowrap; }
.action:hover, .small-action:hover { filter: brightness(1.08); }
.result-block { margin-top: 20px; padding: 18px; min-height: 90px; background: #111318; border-left: 3px solid var(--violet); }
.result-label { display: block; color: var(--muted); font-size: .72rem; text-transform: uppercase; letter-spacing: .1em; }
output { display: block; margin-top: 8px; overflow-wrap: anywhere; color: var(--violet); font: 500 1.2rem ui-monospace, "Cascadia Code", monospace; }
.error { color: var(--danger); font-size: .83rem; line-height: 1.5; }

.fraction-inputs { display: grid; grid-template-columns: 1fr auto 1fr auto 80px auto; gap: 8px; align-items: center; }
.fraction-inputs span { color: var(--muted); }
.base-prefix { font-size: .75rem; text-transform: uppercase; }
.fraction-summary { display: flex; justify-content: space-between; gap: 20px; margin-top: 20px; padding: 16px; background: #111318; }
.fraction-summary strong { color: var(--amber); font: 500 1.05rem ui-monospace, "Cascadia Code", monospace; overflow-wrap: anywhere; }
.fraction-summary span { color: var(--muted); font-size: .8rem; white-space: nowrap; }
.digit-strip { display: flex; flex-wrap: wrap; gap: 4px; margin-top: 10px; max-height: 80px; overflow: auto; }
.digit-strip span { min-width: 24px; padding: 4px; text-align: center; font: .78rem ui-monospace, "Cascadia Code", monospace; border: 1px solid var(--line); }
.period-digit { color: #111318; background: var(--amber); border-color: var(--amber) !important; }
.prefix-digit { color: var(--muted); }
.chart-heading { display: flex; justify-content: space-between; margin: 26px 0 8px; color: var(--muted); font-size: .72rem; text-transform: uppercase; letter-spacing: .08em; }
.chart-scroll { overflow-x: auto; }
.panel-actions { margin-top: 10px; }
.period-chart { display: block; min-width: 680px; width: 100%; background: #111318; }
.axis { stroke: #4a505b; stroke-width: 1; }
.period-bar { fill: var(--amber); }
.terminating-bar { fill: var(--mint); }
.period-chart text { fill: #777e89; font: 10px ui-monospace, "Cascadia Code", monospace; }

.inline-action { display: grid; grid-template-columns: 1fr auto; gap: 10px; }
.mono { font-family: ui-monospace, "Cascadia Code", monospace; }
.bit-cells { display: flex; flex-wrap: wrap; gap: 7px; margin: 24px 0; }
.bit { display: grid; place-items: center; width: 54px; height: 58px; border: 1px solid var(--line); font: 500 1.35rem ui-monospace, "Cascadia Code", monospace; }
.bit-one { color: #111318; background: var(--mint); border-color: var(--mint); }
.bit-zero { color: var(--muted); background: #101217; }
.bit-unknown { color: #111318; background: var(--violet); border-color: var(--violet); animation: pulse 2.4s ease-in-out infinite; }
@keyframes pulse { 50% { box-shadow: 0 0 0 5px #a99cff1c; } }
.metrics { display: grid; grid-template-columns: repeat(4, 1fr); gap: 1px; background: var(--line); border: 1px solid var(--line); }
.metrics div { background: var(--surface); padding: 16px; }
.metrics dt { color: var(--muted); font-size: .72rem; text-transform: uppercase; }
.metrics dd { margin: 8px 0 0; font: 500 .95rem ui-monospace, "Cascadia Code", monospace; }
.candidate-list { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 14px; }
.candidate-list span { padding: 5px 8px; background: #101217; color: var(--muted); font: .75rem ui-monospace, "Cascadia Code", monospace; }

.constraint-input { resize: vertical; min-height: 126px; line-height: 1.65; }
.constraint-controls { display: grid; grid-template-columns: minmax(160px, 1fr) minmax(180px, 1fr) auto; gap: 12px; align-items: end; margin: 18px 0 22px; }
.constraint-status { margin: 12px 0 18px; padding: 13px 15px; border-left: 3px solid; background: #111318; font-size: .84rem; }
.success-status { color: var(--mint); border-color: var(--mint); }
.contradiction-status { color: var(--danger); border-color: var(--danger); }
.explanation-list { margin-top: 24px; border: 1px solid var(--line); background: #111318; }
.explanation-list h3 { margin: 0; padding: 14px 16px; border-bottom: 1px solid var(--line); color: var(--muted); font-size: .76rem; text-transform: uppercase; letter-spacing: .08em; }
.explanation-row { display: grid; grid-template-columns: 72px 36px 1fr; gap: 12px; padding: 11px 16px; border-bottom: 1px solid #282d36; color: var(--muted); font-size: .78rem; line-height: 1.45; }
.explanation-row:last-child { border-bottom: 0; }
.explanation-index, .explanation-value { color: var(--ink); font-family: ui-monospace, "Cascadia Code", monospace; }
.explanation-value { color: var(--violet); font-weight: 800; }
.contradiction-row { background: #3b1f244d; color: var(--danger); }
.contradiction-row .explanation-value { color: var(--danger); }

footer { max-width: 1320px; margin: 0 auto; padding: 24px 36px 44px; border-top: 1px solid var(--line); display: flex; justify-content: space-between; color: var(--muted); font-size: .75rem; }
.loading-shell { min-height: 100vh; display: grid; place-content: center; text-align: center; color: var(--muted); }
.loading-mark { color: var(--mint); font: 500 2rem ui-monospace, "Cascadia Code", monospace; }
#blazor-error-ui { display: none; position: fixed; inset: auto 0 0; padding: 14px; background: #6b2525; color: white; z-index: 1000; }
#blazor-error-ui .dismiss { float: right; border: 0; background: transparent; color: white; }

@media (max-width: 880px) {
    .hero { align-items: flex-start; padding-top: 48px; }
    .hero-mark { display: none; }
    .tool-grid { grid-template-columns: 1fr; }
    .bits-panel, .constraints-panel { grid-column: auto; }
    .metrics { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 560px) {
    .hero, main, footer { padding-left: 18px; padding-right: 18px; }
    .panel { padding: 20px; }
    .fraction-inputs { grid-template-columns: 1fr auto 1fr; }
    .fraction-inputs .base-prefix { grid-column: 1; }
    .fraction-inputs .small-action { grid-column: 1 / -1; }
    .inline-action { grid-template-columns: 1fr; }
    .constraint-controls { grid-template-columns: 1fr; }
    .share-toolbar { grid-template-columns: 1fr; }
    .toolbar-actions { justify-content: stretch; }
    .toolbar-actions .secondary-action { flex: 1 1 auto; }
    .explanation-row { grid-template-columns: 58px 24px 1fr; padding: 10px; gap: 8px; }
    .metrics { grid-template-columns: 1fr; }
    footer { flex-direction: column; gap: 8px; }
}