:root {
  color-scheme: dark;
  --bg: #07101e;
  --surface: #0d1829;
  --surface-2: #122138;
  --surface-3: #172a46;
  --text: #f4f8ff;
  --muted: #9eb0c8;
  --line: #263b57;
  --primary: #66b4ff;
  --primary-strong: #2d93f4;
  --accent: #52e0a5;
  --warning: #ffc45c;
  --danger: #ff7b87;
  --shadow: 0 24px 70px rgba(0, 0, 0, 0.28);
  --radius-xl: 28px;
  --radius-lg: 20px;
  --radius-md: 14px;
}

html[data-theme="light"] {
  color-scheme: light;
  --bg: #eef4fb;
  --surface: #ffffff;
  --surface-2: #f6f9fd;
  --surface-3: #eaf2fb;
  --text: #13233a;
  --muted: #5e7189;
  --line: #d5e1ee;
  --primary: #0869c8;
  --primary-strong: #0058aa;
  --accent: #087d57;
  --warning: #9a6500;
  --danger: #c63143;
  --shadow: 0 24px 60px rgba(39, 71, 108, 0.13);
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html { min-height: 100%; background: var(--bg); }
body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(circle at 12% 0%, color-mix(in srgb, var(--primary) 15%, transparent), transparent 34rem),
    radial-gradient(circle at 100% 18%, color-mix(in srgb, var(--accent) 10%, transparent), transparent 30rem),
    var(--bg);
  color: var(--text);
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.5;
}
button, input, select { font: inherit; }
button { color: inherit; }
button:not(:disabled) { cursor: pointer; }
button:disabled { cursor: not-allowed; opacity: .45; }
svg { width: 1.25rem; height: 1.25rem; fill: currentColor; }
.sr-only { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; }

.page-shell { width: min(1180px, calc(100% - 32px)); margin: 0 auto; padding: 48px 0 36px; }
.hero { display: flex; align-items: flex-start; justify-content: space-between; gap: 24px; margin-bottom: 28px; }
.hero__brand { display: flex; align-items: flex-start; gap: 18px; }
.hero__icon { display: grid; place-items: center; width: 62px; height: 62px; flex: 0 0 auto; border-radius: 20px; color: #06101e; background: linear-gradient(145deg, #7ec6ff, #4ea7ff); box-shadow: 0 14px 40px color-mix(in srgb, var(--primary) 28%, transparent); }
.hero__icon svg { width: 32px; height: 32px; }
.eyebrow, .section-kicker { display: block; margin: 0 0 5px; color: var(--primary); font-size: .74rem; font-weight: 800; letter-spacing: .12em; text-transform: uppercase; }
h1, h2, p { margin-top: 0; }
h1 { margin-bottom: 8px; font-size: clamp(2rem, 5vw, 3.55rem); line-height: 1.02; letter-spacing: -.055em; }
h2 { margin-bottom: 6px; font-size: clamp(1.22rem, 2.6vw, 1.65rem); letter-spacing: -.025em; }
.hero__description { max-width: 700px; margin-bottom: 0; color: var(--muted); font-size: 1.02rem; }
.hero__actions { display: flex; flex-wrap: wrap; justify-content: flex-end; gap: 10px; }
.icon-button, .primary-button, .secondary-button, .reset-button, .text-button { border: 0; border-radius: 12px; font-weight: 750; transition: transform .16s ease, border-color .16s ease, background .16s ease; }
.icon-button:hover, .primary-button:hover, .secondary-button:hover, .reset-button:hover { transform: translateY(-1px); }
.icon-button { display: inline-flex; align-items: center; gap: 8px; min-height: 42px; padding: 0 14px; border: 1px solid var(--line); background: color-mix(in srgb, var(--surface) 86%, transparent); }
html[data-theme="dark"] .theme-icon--moon, html[data-theme="light"] .theme-icon--sun { display: none; }

.control-panel, .history-panel { padding: 24px; border: 1px solid var(--line); border-radius: var(--radius-xl); background: color-mix(in srgb, var(--surface) 94%, transparent); box-shadow: var(--shadow); }
.control-panel { margin-bottom: 22px; }
.panel-heading { display: flex; justify-content: space-between; align-items: flex-start; gap: 16px; margin-bottom: 20px; }
.panel-heading h2 { margin-bottom: 0; }
.storage-status { padding: 8px 12px; border-radius: 10px; background: color-mix(in srgb, var(--danger) 12%, transparent); color: var(--danger); font-size: .82rem; font-weight: 700; }
.controls-grid { display: grid; grid-template-columns: 1.35fr 1fr .8fr 1fr; gap: 16px; align-items: start; }
.profile-control { display: grid; gap: 10px; }
.button-row { display: flex; flex-wrap: wrap; gap: 10px; }
.button-row--compact .secondary-button { flex: 1; min-width: 110px; }

.input-group { display: grid; gap: 7px; color: var(--muted); font-size: .83rem; font-weight: 700; }
.input-shell { display: flex; align-items: center; min-height: 48px; overflow: hidden; border: 1px solid var(--line); border-radius: 13px; background: var(--surface-2); transition: border-color .16s ease, box-shadow .16s ease; }
.input-shell:focus-within { border-color: var(--primary); box-shadow: 0 0 0 3px color-mix(in srgb, var(--primary) 15%, transparent); }
.input-shell.is-invalid { border-color: var(--danger); box-shadow: 0 0 0 3px color-mix(in srgb, var(--danger) 11%, transparent); }
.input-shell input, .input-shell select, .name-field input { min-width: 0; width: 100%; border: 0; outline: 0; background: transparent; color: var(--text); }
.input-shell input, .input-shell select { min-height: 46px; padding: 0 13px; }
.input-shell--select { position: relative; }
.input-shell--select select { appearance: none; padding-right: 35px; }
.input-shell--select::after { content: "⌄"; position: absolute; right: 13px; top: 50%; transform: translateY(-55%); pointer-events: none; color: var(--muted); }
.input-prefix, .input-suffix { flex: 0 0 auto; color: var(--muted); font-weight: 750; }
.input-prefix { padding-left: 13px; }
.input-suffix { padding-right: 13px; }
.input-help { min-height: 17px; color: var(--muted); font-weight: 500; }
.input-error { min-height: 17px; color: var(--danger); font-weight: 650; }

.fuel-grid { display: grid; grid-template-columns: 1fr 56px 1fr; align-items: stretch; margin-bottom: 22px; }
.fuel-card { position: relative; padding: 24px; border: 1px solid var(--line); border-radius: var(--radius-xl); background: color-mix(in srgb, var(--surface) 96%, transparent); box-shadow: var(--shadow); transition: border-color .2s ease, transform .2s ease; }
.fuel-card.is-winner { border-color: color-mix(in srgb, var(--accent) 65%, var(--line)); transform: translateY(-3px); }
.fuel-card__header { display: flex; align-items: center; gap: 12px; margin-bottom: 22px; }
.fuel-badge { display: grid; place-items: center; width: 36px; height: 36px; flex: 0 0 auto; border-radius: 11px; color: #06101e; font-weight: 900; }
.fuel-badge--first { background: var(--primary); }
.fuel-badge--second { background: var(--accent); }
.name-field { flex: 1; min-width: 0; }
.name-field input { padding: 3px 0; font-size: 1.25rem; font-weight: 850; }
.winner-label { flex: 0 0 auto; padding: 6px 9px; border-radius: 999px; background: color-mix(in srgb, var(--accent) 14%, transparent); color: var(--accent); font-size: .7rem; font-weight: 850; text-transform: uppercase; letter-spacing: .07em; }
.field-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.input-group--wide { grid-column: 1 / -1; }
.blend-summary { display: flex; align-items: flex-start; justify-content: space-between; gap: 14px; margin-top: 16px; padding: 15px; border: 1px solid color-mix(in srgb, var(--primary) 35%, var(--line)); border-radius: 14px; background: color-mix(in srgb, var(--primary) 8%, transparent); }
.blend-summary__label { display: block; margin-bottom: 3px; color: var(--muted); font-size: .72rem; font-weight: 800; text-transform: uppercase; letter-spacing: .08em; }
.blend-summary strong { display: block; margin-bottom: 4px; }
.blend-summary p { margin: 0; color: var(--muted); font-size: .82rem; }
.blend-summary__badge { min-width: 56px; padding: 7px 9px; border-radius: 10px; background: var(--primary); color: #06101e; text-align: center; font-weight: 900; }
.fuel-results { display: grid; grid-template-columns: 1fr 1fr; gap: 10px; margin-top: 20px; }
.fuel-results > div, .savings-grid > div { min-width: 0; padding: 14px; border: 1px solid var(--line); border-radius: 14px; background: var(--surface-2); }
.fuel-results span, .savings-grid span { display: block; margin-bottom: 3px; color: var(--muted); font-size: .73rem; font-weight: 700; }
.fuel-results strong, .savings-grid strong { display: block; overflow-wrap: anywhere; font-size: .97rem; }
.versus { display: grid; place-items: center; z-index: 2; align-self: center; width: 48px; height: 48px; margin: 0 4px; border: 1px solid var(--line); border-radius: 50%; background: var(--surface-3); color: var(--muted); font-size: .75rem; font-weight: 900; }

.break-even-card, .result-card { display: flex; gap: 18px; padding: 24px; border: 1px solid var(--line); border-radius: var(--radius-xl); background: var(--surface); box-shadow: var(--shadow); }
.break-even-card { align-items: center; margin-bottom: 22px; background: linear-gradient(135deg, color-mix(in srgb, var(--warning) 10%, var(--surface)), var(--surface)); }
.break-even-card__icon { display: grid; place-items: center; width: 50px; height: 50px; flex: 0 0 auto; border-radius: 16px; background: color-mix(in srgb, var(--warning) 18%, transparent); color: var(--warning); font-size: 1.5rem; font-weight: 900; }
.break-even-card p { margin-bottom: 0; color: var(--muted); }
.result-card { margin-bottom: 22px; background: linear-gradient(135deg, color-mix(in srgb, var(--accent) 12%, var(--surface)), var(--surface)); }
.result-card--empty { background: var(--surface); }
.result-card--tie { background: linear-gradient(135deg, color-mix(in srgb, var(--warning) 10%, var(--surface)), var(--surface)); }
.result-card__icon { display: grid; place-items: center; width: 56px; height: 56px; flex: 0 0 auto; border-radius: 18px; background: var(--accent); color: #06140e; }
.result-card--empty .result-card__icon { background: var(--surface-3); color: var(--muted); }
.result-card--tie .result-card__icon { background: var(--warning); color: #211600; }
.result-card__icon svg { width: 30px; height: 30px; }
.result-card__content { min-width: 0; flex: 1; }
.result-card__content > p { color: var(--muted); }
.savings-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin-top: 18px; }
.result-actions { display: flex; flex-wrap: wrap; gap: 10px; margin-top: 18px; }
.primary-button, .secondary-button { min-height: 42px; padding: 0 15px; }
.primary-button { background: var(--primary-strong); color: #fff; }
.primary-button--danger { background: var(--danger); color: #fff; }
.secondary-button { border: 1px solid var(--line); background: var(--surface-2); }
.secondary-button--danger { color: var(--danger); }

.history-panel { margin-bottom: 22px; }
.history-list { display: grid; gap: 10px; }
.history-empty { padding: 24px; border: 1px dashed var(--line); border-radius: 14px; color: var(--muted); text-align: center; }
.history-item { display: grid; grid-template-columns: minmax(0, 1fr) auto; gap: 16px; padding: 16px; border: 1px solid var(--line); border-radius: 15px; background: var(--surface-2); }
.history-item__top { display: flex; flex-wrap: wrap; align-items: center; gap: 8px 12px; margin-bottom: 8px; }
.history-item__top strong { font-size: 1rem; }
.history-item__date { color: var(--muted); font-size: .78rem; }
.history-item__details { display: flex; flex-wrap: wrap; gap: 6px 14px; color: var(--muted); font-size: .82rem; }
.history-item__actions { display: flex; align-items: center; gap: 8px; }
.text-button { padding: 6px 0; background: transparent; color: var(--primary); }
.text-button--danger { color: var(--danger); }

.page-footer { display: flex; justify-content: space-between; align-items: center; gap: 18px; padding: 6px 2px; color: var(--muted); font-size: .83rem; }
.page-footer p { margin-bottom: 0; }
.reset-button { display: inline-flex; align-items: center; gap: 8px; padding: 10px 13px; background: transparent; color: var(--muted); }
.reset-button:hover { background: var(--surface); color: var(--text); }

.app-dialog { width: min(480px, calc(100% - 28px)); padding: 0; border: 1px solid var(--line); border-radius: 22px; background: var(--surface); color: var(--text); box-shadow: var(--shadow); }
.app-dialog::backdrop { background: rgba(3, 8, 16, .72); backdrop-filter: blur(5px); }
.app-dialog form { padding: 24px; }
.dialog-heading p { color: var(--muted); }
.dialog-actions { display: flex; justify-content: flex-end; gap: 10px; margin-top: 22px; }
.toast { position: fixed; right: 20px; bottom: 20px; z-index: 20; max-width: min(420px, calc(100% - 40px)); padding: 13px 16px; border: 1px solid var(--line); border-radius: 13px; background: var(--surface-3); color: var(--text); box-shadow: var(--shadow); font-weight: 700; }

@media (max-width: 960px) {
  .controls-grid { grid-template-columns: 1fr 1fr; }
  .profile-control { grid-column: 1 / -1; grid-template-columns: 1fr auto; align-items: end; }
  .fuel-grid { grid-template-columns: 1fr; gap: 14px; }
  .versus { margin: -8px auto; }
}

@media (max-width: 680px) {
  .page-shell { width: min(100% - 20px, 1180px); padding-top: 22px; }
  .hero { display: grid; }
  .hero__brand { gap: 12px; }
  .hero__icon { width: 48px; height: 48px; border-radius: 15px; }
  .hero__icon svg { width: 25px; height: 25px; }
  h1 { font-size: 2.05rem; }
  .hero__actions { justify-content: flex-start; }
  .control-panel, .history-panel, .fuel-card, .break-even-card, .result-card { padding: 18px; border-radius: 21px; }
  .controls-grid, .field-grid, .savings-grid { grid-template-columns: 1fr; }
  .profile-control { grid-template-columns: 1fr; }
  .input-group--wide { grid-column: auto; }
  .fuel-results { grid-template-columns: 1fr 1fr; }
  .winner-label { font-size: .62rem; }
  .result-card, .break-even-card { align-items: flex-start; gap: 12px; }
  .result-card__icon, .break-even-card__icon { width: 44px; height: 44px; border-radius: 13px; }
  .result-card__icon svg { width: 24px; height: 24px; }
  .result-actions > button { flex: 1 1 145px; }
  .history-item { grid-template-columns: 1fr; }
  .history-item__actions { justify-content: flex-start; }
  .page-footer { align-items: flex-start; flex-direction: column; }
}

@media (max-width: 420px) {
  .fuel-results { grid-template-columns: 1fr; }
  .hero__actions .icon-button span { display: none; }
  .icon-button { padding: 0 12px; }
}