:root {
  color-scheme: light;
  --bg: #eef3f8;
  --raise: #ffffff;
  --ink: #142033;
  --muted: #526070;
  --line: #d5e0ea;
  --accent: #1d4e89;
  --accent-ink: #f4f8fc;
  --save: #0c7a4b;
  --save-bg: #e7f6ef;
  --warn: #9a3412;
  --warn-bg: #fde8e4;
  --danger: #9f2d2d;
  --danger-bg: #fdecec;
  --pay: #1d4e89;
  --extra: #8a5a2a;
  --base: #3d6f8f;
  --header: rgba(238, 243, 248, 0.92);
  --shadow: 0 12px 32px rgba(20, 32, 51, 0.06);
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0f1720;
  --raise: #182230;
  --ink: #e8eef5;
  --muted: #a9b7c6;
  --line: #2c3b4d;
  --accent: #8eb7e8;
  --accent-ink: #0f1720;
  --save: #7dcea9;
  --save-bg: #143328;
  --warn: #f0b4a0;
  --warn-bg: #3a241e;
  --danger: #ffb4b0;
  --danger-bg: #3a2020;
  --pay: #8eb7e8;
  --extra: #d7b089;
  --base: #8eb7d4;
  --header: rgba(15, 23, 32, 0.92);
  --shadow: none;
}

* { box-sizing: border-box; }
html { scroll-behavior: smooth; }

body {
  margin: 0;
  min-height: 100vh;
  background:
    radial-gradient(900px 320px at 0% -10%, rgba(29, 78, 137, 0.1), transparent 50%),
    var(--bg);
  color: var(--ink);
  font-family: system-ui, "Segoe UI", sans-serif;
  font-size: 16px;
  line-height: 1.5;
}

a { color: var(--accent); }
a:hover { text-decoration: none; }

.skip {
  position: absolute;
  left: 12px;
  top: -40px;
  background: var(--accent);
  color: var(--accent-ink);
  padding: 8px 12px;
  z-index: 5;
}
.skip:focus { top: 12px; }

.site-header, .site-footer, .wrap { width: min(1080px, calc(100% - 28px)); margin-inline: auto; }

.site-header {
  display: flex;
  align-items: center;
  gap: 12px 16px;
  min-height: 64px;
  position: sticky;
  top: 0;
  z-index: 3;
  background: var(--header);
  backdrop-filter: blur(10px);
  flex-wrap: wrap;
  padding: 8px 0;
}

.logo {
  color: var(--ink);
  text-decoration: none;
  font-weight: 720;
  letter-spacing: -0.03em;
  font-size: 18px;
}

.site-header nav { display: flex; gap: 12px; flex-wrap: wrap; }
.site-header nav a { color: var(--muted); text-decoration: none; font-size: 14px; }
.site-header nav a[aria-current="page"], .site-header nav a:hover { color: var(--ink); }

.theme-btn, .btn {
  border: 1px solid var(--line);
  background: var(--raise);
  color: var(--ink);
  border-radius: 999px;
  min-height: 40px;
  padding: 0 14px;
  font: inherit;
  cursor: pointer;
}
.theme-btn { margin-left: auto; }
.btn-primary { background: var(--accent); color: var(--accent-ink); border-color: transparent; }
.btn-ghost { background: transparent; }
.btn:disabled { opacity: 0.45; cursor: not-allowed; }

.wrap { padding: 8px 0 56px; }
.crumbs { color: var(--muted); font-size: 13px; margin: 8px 0 16px; }
.crumbs a { color: inherit; }

.layout { display: grid; gap: 22px; }
.layout > div:first-child { min-width: 0; }

h1, h2 {
  font-weight: 680;
  letter-spacing: -0.03em;
  line-height: 1.15;
}
h1 { font-size: clamp(30px, 8vw, 46px); margin: 0 0 10px; }
h2 { font-size: 26px; margin: 32px 0 12px; }
.lead { font-size: 18px; color: var(--muted); margin: 0 0 16px; max-width: 62ch; }

.panel, .result, .catalog a, .faq details, .related a {
  background: var(--raise);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
}
.panel { padding: 16px; }

.presets { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 12px; }
.presets .btn { min-height: 36px; font-size: 14px; }

.period { border: 0; margin: 0 0 12px; padding: 0; }
.period legend { font-weight: 680; margin-bottom: 8px; }
.period-options { display: flex; flex-wrap: wrap; gap: 8px; }
.period-option {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  min-height: 40px;
  padding: 0 12px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: transparent;
}
.period-option:has(input:checked) {
  border-color: var(--accent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
}
fieldset.invalid { outline: 2px solid var(--danger); border-radius: 12px; }

.fields, .plan-grid { display: grid; gap: 12px; }
.plan { border: 0; border-top: 1px solid var(--line); margin: 14px 0 0; padding: 12px 0 0; }
.plan:first-of-type { border-top: 0; margin-top: 0; padding-top: 0; }
.plan legend { font-weight: 680; padding: 0; }

label.field { display: flex; flex-direction: column; gap: 6px; font-size: 14px; }
.field-name { font-weight: 680; }
.hint, .field-error { margin: 0; font-size: 12px; color: var(--muted); }
.field-error:empty { display: none; }
.field-error { color: var(--danger); }

input, select {
  width: 100%;
  border: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  border-radius: 12px;
  min-height: 44px;
  padding: 10px 12px;
  font: inherit;
}
input:focus, select:focus { outline: 2px solid var(--accent); border-color: transparent; }
input.invalid, select.invalid { border-color: var(--danger); background: var(--danger-bg); }

.actions { display: flex; flex-wrap: wrap; gap: 8px; margin-top: 14px; }
.history { margin-top: 16px; }
.history-label { margin: 0 0 8px; color: var(--muted); font-size: 13px; }

.result { padding: 16px 16px 8px; }
.result-kicker {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px;
  margin: 0;
  color: var(--muted);
  font-size: 13px;
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.badge {
  text-transform: none;
  letter-spacing: 0;
  border-radius: 999px;
  padding: 2px 8px;
  background: var(--save);
  color: #f4fff8;
  font-size: 13px;
  font-weight: 700;
}
:root[data-theme="dark"] .badge { color: #102018; }
.badge-warn { background: var(--warn-bg); color: var(--warn); border: 1px solid var(--warn); }
.badge-pay { background: var(--accent); color: var(--accent-ink); }
.result-main {
  margin: 6px 0;
  font-size: clamp(32px, 8vw, 44px);
  letter-spacing: -0.04em;
  font-variant-numeric: tabular-nums;
  font-weight: 720;
}
.result-main.is-fresh { animation: rise 240ms ease; }
.result-formula, .result-note, .result-idle, .chart-caption { color: var(--muted); }
.result-warn { color: var(--danger); font-weight: 700; }
.result-bad { color: var(--danger); }
.result-lines { margin: 12px 0; }
.result-lines div {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  padding: 8px 0;
  border-top: 1px dashed var(--line);
}
.result-lines dt { color: var(--muted); }
.result-lines dd { margin: 0; text-align: right; font-variant-numeric: tabular-nums; }

.compare-cols { display: grid; grid-template-columns: repeat(auto-fit, minmax(128px, 1fr)); gap: 8px; margin: 10px 0; }
.compare-cols div { border: 1px solid var(--line); border-radius: 12px; padding: 10px; }
.compare-cols .is-best { border-color: var(--accent); box-shadow: inset 0 0 0 1px var(--accent); }
.compare-cols span, .compare-cols small { display: block; color: var(--muted); font-size: 12px; }
.compare-cols strong { display: block; margin: 4px 0; font-size: 18px; font-variant-numeric: tabular-nums; }
.compare-cols small { margin-top: 2px; }

.bar { display: flex; height: 10px; border-radius: 999px; overflow: hidden; background: var(--line); margin: 8px 0 4px; }
.bar-pay { background: var(--pay); }
.bar-save { background: var(--save); }
.bar-base { background: var(--base); }
.bar-extra { background: var(--extra); }
.bar-warn { background: var(--warn); }

.chart { width: 100%; height: 140px; display: block; }
.chart polyline { fill: none; stroke: var(--accent); stroke-width: 2.5; stroke-linejoin: round; stroke-linecap: round; }
.chart-fill { fill: var(--accent); opacity: 0.16; }
.chart-axis { stroke: var(--line); stroke-width: 1; }
.chart-label { fill: var(--muted); font-size: 11px; }
.chart-caption { margin: 8px 0 0; font-size: 12px; }

.steps { width: 100%; border-collapse: collapse; font-size: 14px; margin: 8px 0 16px; }
.steps th, .steps td { text-align: left; padding: 8px 6px; border-bottom: 1px solid var(--line); vertical-align: top; }
.steps td:not(:first-child), .steps th:not(:first-child) { text-align: right; font-variant-numeric: tabular-nums; }
tr.is-best td { font-weight: 720; background: color-mix(in srgb, var(--accent) 10%, transparent); }

.prose p { max-width: 68ch; }
.faq { display: grid; gap: 10px; }
.faq details { padding: 12px 16px; box-shadow: none; }
.faq summary { cursor: pointer; font-weight: 680; }
.related, .catalog { display: grid; grid-template-columns: 1fr; gap: 10px; }
.related a, .catalog a { display: block; padding: 14px 16px; text-decoration: none; color: var(--ink); }
.related a span, .catalog a span { display: block; color: var(--muted); font-size: 14px; margin-top: 4px; }

.site-footer { padding: 8px 0 40px; color: var(--muted); font-size: 14px; }
.footer-links { display: flex; flex-wrap: wrap; gap: 8px 14px; margin-bottom: 12px; }
.footer-links a { color: inherit; }

@keyframes rise {
  from { opacity: 0.35; transform: translateY(6px); }
  to { opacity: 1; transform: none; }
}

@media (min-width: 720px) {
  .fields { grid-template-columns: 1fr 1fr; }
  .plan-grid { grid-template-columns: 1.2fr 0.8fr 1fr; }
  .related, .catalog { grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); }
}

@media (min-width: 960px) {
  .layout { grid-template-columns: minmax(0, 1.2fr) minmax(300px, 0.8fr); align-items: start; }
  .result { grid-column: 2; grid-row: 1 / span 2; position: sticky; top: 84px; }
  .text-col { grid-column: 1; }
  .site-header { flex-wrap: nowrap; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .result-main.is-fresh { animation: none; }
}