/* Dual Fuel Optimizer — phone-first design system. No build step.
 * Identity: cold-to-hot duality — ice cyan for the heat pump, flame orange
 * for the gas furnace, on a deep night-sky navy. */

:root {
  --bg: #0d1322;
  --surface: #141c30;
  --surface-2: #1b2542;
  --line: #273459;
  --line-strong: #36466f;
  --text: #eef2fb;
  --muted: #93a1c2;
  --ice: #38bdf8;
  --ice-soft: rgba(56, 189, 248, 0.12);
  --flame: #fb923c;
  --flame-soft: rgba(251, 146, 60, 0.12);
  --amber: #fbbf24;
  --warn: #fbbf24;
  --bad: #f87171;
  --grad-brand: linear-gradient(90deg, #38bdf8, #fb923c);
  --grad-cta: linear-gradient(135deg, #f97316, #fbbf24);
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 8px 24px rgba(2, 6, 18, 0.45);
  --tabbar-h: 64px;
}

* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 400 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  padding-bottom: calc(var(--tabbar-h) + env(safe-area-inset-bottom));
}
h1, h2, h3, p { margin: 0; }
button { font: inherit; cursor: pointer; -webkit-tap-highlight-color: transparent; }

/* ---------- app bar ---------- */
.appbar {
  display: flex; align-items: center; gap: 12px;
  max-width: 620px; margin: 0 auto;
  padding: calc(14px + env(safe-area-inset-top)) 20px 10px;
}
.logo { width: 40px; height: 40px; border-radius: 11px; }
.appbar-title { flex: 1; min-width: 0; }
.appbar-title h1 { font-size: 1.1rem; font-weight: 750; letter-spacing: -0.01em; }
.appbar-title p { font-size: 0.75rem; color: var(--muted); }
.iconbtn {
  display: grid; place-items: center;
  width: 42px; height: 42px; border-radius: 12px;
  background: var(--surface); border: 1px solid var(--line);
}
.iconbtn:active { background: var(--surface-2); }

/* ---------- layout / tabs ---------- */
main { max-width: 620px; margin: 0 auto; padding: 6px 16px 24px; }
.tab { display: none; flex-direction: column; gap: 14px; }
.tab.active { display: flex; }

/* ---------- cards & steps ---------- */
.card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 18px;
}
.step-head { display: flex; gap: 12px; align-items: flex-start; margin-bottom: 14px; }
.step-head.no-num { margin-bottom: 10px; }
.step-head h2 { font-size: 1.02rem; font-weight: 700; letter-spacing: -0.01em; }
.step-head p { font-size: 0.78rem; color: var(--muted); margin-top: 2px; }
.step-num {
  flex: none; display: grid; place-items: center;
  width: 28px; height: 28px; margin-top: 1px;
  border-radius: 50%;
  background: var(--surface-2); border: 1px solid var(--line-strong);
  font-size: 0.82rem; font-weight: 700; color: var(--muted);
  transition: all 0.25s ease;
}
.step-num.done {
  background: var(--ice); border-color: var(--ice); color: #06263c;
}

/* ---------- forms ---------- */
label { display: block; font-size: 0.8rem; font-weight: 550; color: var(--muted); margin: 12px 0 6px; }
label:first-child { margin-top: 0; }
label .opt { font-weight: 400; opacity: 0.75; }
/* Inside a grid, every cell needs the SAME top margin or the boxes in one
 * row sit at different heights (label:first-child only zeroes the first). */
.grid2 > label { margin-top: 14px; }
.grid2 > label:nth-child(-n+2) { margin-top: 0; }
input, select {
  width: 100%;
  background: var(--surface-2);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-size: 1rem;
  padding: 12px 14px;
  min-height: 48px;
  appearance: none;
}
input::placeholder { color: #5b6b93; }
input:focus, select:focus { outline: 2px solid var(--ice); outline-offset: -1px; border-color: transparent; }
input[type="search"]::-webkit-search-cancel-button { -webkit-appearance: none; }
select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%2393a1c2' stroke-width='2' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat; background-position: right 14px center;
  padding-right: 36px;
}
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0 12px; }
.grid2 label { min-width: 0; }
.grid2 .span2 { grid-column: 1 / -1; }

.unit-wrap {
  display: flex; align-items: center; gap: 0;
  background: var(--surface-2); border: 1px solid var(--line); border-radius: var(--radius-sm);
  margin-top: 0;
}
.unit-wrap:focus-within { outline: 2px solid var(--ice); outline-offset: -1px; }
.unit-wrap input { background: none; border: none; min-width: 0; flex: 1; }
.unit-wrap input:focus { outline: none; }
.unit-wrap .unit { flex: none; font-size: 0.78rem; color: var(--muted); padding: 0 12px 0 4px; }
.unit-wrap .unit:first-child { padding: 0 0 0 12px; }

.field-note { font-size: 0.78rem; color: var(--muted); margin-top: 8px; min-height: 0; }
.field-note.ok { color: var(--ice); }
.field-note.err { color: var(--bad); }
.field-note:empty { margin: 0; }
.mini-link {
  background: none; border: none; color: var(--ice);
  font-size: 0.75rem; font-weight: 600; padding: 0 2px; text-decoration: underline;
}
.linklike {
  background: none; border: none; color: var(--ice);
  font-size: 0.83rem; font-weight: 550; padding: 10px 2px 0; text-align: left;
}
.grp { margin: 16px 0 2px; font-size: 0.72rem; letter-spacing: 0.08em;
  text-transform: uppercase; color: var(--flame); font-weight: 700; }

/* ---------- buttons ---------- */
.primary, .secondary {
  border: none; border-radius: 12px;
  padding: 13px 18px; min-height: 48px;
  font-weight: 700; font-size: 0.95rem;
}
.primary { background: var(--grad-cta); color: #2b1502; }
.primary:active { transform: translateY(1px); filter: brightness(1.06); }
.primary:disabled { opacity: 0.45; cursor: default; }
.secondary { background: var(--surface-2); color: var(--text); border: 1px solid var(--line-strong); }
.secondary:active { background: var(--line); }
.action-row { display: flex; gap: 10px; margin-top: 4px; }
.action-row button { flex: 1; }

/* ---------- HP search ---------- */
.search-results {
  margin-top: 8px;
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  max-height: 320px; overflow-y: auto;
  background: var(--surface-2);
}
.match {
  display: block; width: 100%; text-align: left;
  background: none; border: none; border-bottom: 1px solid var(--line);
  padding: 12px 14px; color: var(--text);
}
.match:last-child { border-bottom: none; }
.match:active, .match:hover { background: var(--ice-soft); }
.match .m-brand { font-weight: 700; font-size: 0.9rem; }
.match .m-sub { font-size: 0.74rem; color: var(--muted); }
.match .m-spec { font-size: 0.74rem; color: var(--ice); margin-top: 3px; }
.match.invalid { opacity: 0.5; }
.match.more-row { color: var(--ice); font-weight: 600; font-size: 0.85rem; text-align: center; }

.selected-unit {
  margin-top: 4px;
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.10), rgba(251, 146, 60, 0.07));
  border: 1px solid rgba(56, 189, 248, 0.45);
  border-radius: var(--radius-sm);
  padding: 14px;
}
.selected-unit .su-head { display: flex; align-items: flex-start; gap: 10px; }
.selected-unit .su-name { flex: 1; font-weight: 750; font-size: 0.95rem; }
.selected-unit .su-series { font-size: 0.75rem; color: var(--muted); font-weight: 400; }
.spec-chips { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 10px; }
.chip {
  font-size: 0.72rem; font-weight: 600; color: var(--text);
  background: rgba(255, 255, 255, 0.06); border: 1px solid var(--line);
  border-radius: 999px; padding: 4px 10px;
}
.chip b { color: var(--ice); }
.chip.hot { background: var(--flame-soft); border-color: rgba(251, 146, 60, 0.5); }
.chip.hot b { color: var(--flame); }

/* ---------- CTA bar ---------- */
.cta-bar {
  position: fixed; left: 0; right: 0;
  bottom: calc(var(--tabbar-h) + env(safe-area-inset-bottom));
  padding: 10px 16px;
  background: linear-gradient(to top, var(--bg) 55%, transparent);
  display: flex; justify-content: center;
  pointer-events: none;
  z-index: 30;
}
.cta-bar button { pointer-events: auto; width: 100%; max-width: 588px; }
.primary.big { font-size: 1.02rem; min-height: 52px; border-radius: 14px; box-shadow: 0 6px 20px rgba(249, 115, 22, 0.3); }
body[data-tab="setup"] main { padding-bottom: 84px; }
body:not([data-tab="setup"]) .cta-bar { display: none; }

/* ---------- bottom tab bar ---------- */
.tabbar {
  position: fixed; left: 0; right: 0; bottom: 0; z-index: 40;
  display: flex;
  height: calc(var(--tabbar-h) + env(safe-area-inset-bottom));
  padding-bottom: env(safe-area-inset-bottom);
  background: rgba(13, 19, 34, 0.92);
  backdrop-filter: blur(14px);
  -webkit-backdrop-filter: blur(14px);
  border-top: 1px solid var(--line);
}
.tabbtn {
  flex: 1; display: flex; flex-direction: column; align-items: center; justify-content: center; gap: 3px;
  background: none; border: none; color: var(--muted);
  font-size: 0.68rem; font-weight: 600;
}
.tabbtn.active { color: var(--flame); }
.tabbtn svg { display: block; }

/* ---------- results ---------- */
.empty-state { text-align: center; padding: 56px 20px; color: var(--muted); }
.empty-state .empty-icon { font-size: 2.6rem; margin-bottom: 10px; }
.empty-state h2 { color: var(--text); font-size: 1.05rem; margin-bottom: 6px; }
.empty-state p { font-size: 0.85rem; max-width: 300px; margin: 0 auto 18px; }

.hero {
  background:
    radial-gradient(120% 140% at 12% 0%, rgba(56, 189, 248, 0.20), transparent 55%),
    radial-gradient(120% 140% at 90% 100%, rgba(251, 146, 60, 0.18), transparent 55%),
    var(--surface);
  border: 1px solid rgba(56, 189, 248, 0.30);
  border-radius: 20px;
  padding: 26px 20px 20px;
  text-align: center;
  box-shadow: var(--shadow);
}
.hero-label { font-size: 0.78rem; font-weight: 700; letter-spacing: 0.09em; text-transform: uppercase; color: var(--muted); }
.hero-value {
  font-size: clamp(3rem, 16vw, 4.2rem);
  font-weight: 800; letter-spacing: -0.03em; line-height: 1.1;
  color: var(--ice);
  background: var(--grad-brand);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
}
.hero-value.warn, .hero-value.blue {
  background: none;
  -webkit-text-fill-color: currentColor;
}
.hero-value.warn { color: var(--flame); }
.hero-value.blue { color: var(--ice); }
.hero-sub { font-size: 0.9rem; color: var(--text); max-width: 340px; margin: 6px auto 0; }
.hero-chips { display: flex; flex-wrap: wrap; gap: 6px; justify-content: center; margin-top: 16px; }

/* annual cost bars */
.abar { margin-top: 12px; }
.abar:first-child { margin-top: 2px; }
.abar .abar-top { display: flex; justify-content: space-between; align-items: baseline; font-size: 0.83rem; }
.abar .abar-name { font-weight: 600; }
.abar .abar-cost { font-weight: 750; font-variant-numeric: tabular-nums; }
.abar .abar-track { height: 12px; border-radius: 6px; background: var(--surface-2); margin-top: 5px; overflow: hidden; }
.abar .abar-fill { height: 100%; border-radius: 6px; background: var(--line-strong); transition: width 0.5s ease; }
.abar.best .abar-fill { background: var(--grad-brand); }
.abar.best .abar-cost { color: var(--amber); }
.abar .abar-detail { font-size: 0.72rem; color: var(--muted); margin-top: 3px; }
.badge {
  display: inline-block; font-size: 0.64rem; font-weight: 800; letter-spacing: 0.06em;
  text-transform: uppercase; color: #2b1502; background: var(--grad-cta);
  border-radius: 999px; padding: 2px 8px; margin-left: 6px; vertical-align: 1px;
}

canvas { width: 100%; height: auto; display: block; border-radius: var(--radius-sm); }

details summary {
  cursor: pointer; font-size: 0.9rem; font-weight: 650; color: var(--ice);
  padding: 2px 0; list-style: none;
}
details summary::-webkit-details-marker { display: none; }
details summary::after { content: " \25BE"; color: var(--muted); }
details[open] summary::after { content: " \25B4"; }
table { width: 100%; border-collapse: collapse; font-size: 0.84rem; margin-top: 10px; }
th, td { text-align: right; padding: 8px 6px; border-bottom: 1px solid var(--line); }
th:first-child, td:first-child { text-align: left; color: var(--muted); font-weight: 500; }
th { color: var(--muted); font-weight: 600; }
.tbl-title { margin: 16px 0 0; font-size: 0.78rem; font-weight: 700; letter-spacing: 0.06em; text-transform: uppercase; color: var(--flame); }

.note-warn {
  background: rgba(251, 191, 36, 0.08); border: 1px solid rgba(251, 191, 36, 0.4);
  color: #fde68a; border-radius: var(--radius-sm);
  padding: 10px 12px; font-size: 0.8rem; margin-top: 12px;
}

/* ---------- compare ---------- */
.scenario-list { display: flex; flex-direction: column; gap: 10px; margin-bottom: 14px; }
.scenario-list .empty { font-size: 0.82rem; color: var(--muted); padding: 6px 0; }
.scn {
  background: var(--surface-2); border: 1px solid var(--line);
  border-radius: var(--radius-sm); padding: 12px;
}
.scn-row { display: flex; gap: 8px; align-items: center; }
.scn-name { flex: 1; min-height: 42px; padding: 8px 12px; font-size: 0.9rem; font-weight: 600; }
.scn-del {
  flex: none; width: 42px; height: 42px; display: grid; place-items: center;
  background: none; border: 1px solid var(--line); border-radius: 10px;
  color: var(--muted); font-size: 1.1rem;
}
.scn-row2 { display: flex; gap: 8px; align-items: center; margin-top: 8px; }
.scn-backup { min-height: 42px; padding: 8px 32px 8px 12px; font-size: 0.82rem; flex: none; width: auto; }
.scn-meta { flex: 1; font-size: 0.74rem; color: var(--muted); text-align: right; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.rank-card {
  background: var(--surface); border: 1px solid var(--line);
  border-radius: var(--radius); padding: 16px; margin-bottom: 10px;
}
.rank-card.best { border-color: rgba(251, 146, 60, 0.5);
  background: linear-gradient(135deg, rgba(56, 189, 248, 0.07), var(--surface) 45%, rgba(251, 146, 60, 0.06)); }
.rank-head { display: flex; align-items: center; gap: 10px; }
.rank-pos {
  flex: none; width: 28px; height: 28px; display: grid; place-items: center;
  border-radius: 50%; background: var(--surface-2); border: 1px solid var(--line-strong);
  font-size: 0.82rem; font-weight: 800; color: var(--muted);
}
.rank-card.best .rank-pos { background: var(--grad-cta); border-color: transparent; color: #2b1502; }
.rank-name { flex: 1; font-weight: 700; font-size: 0.92rem; min-width: 0; }
.rank-mode { font-size: 0.7rem; color: var(--muted); font-weight: 500; }
.rank-cost { text-align: right; font-weight: 800; font-size: 1.15rem; font-variant-numeric: tabular-nums; }
.rank-card.best .rank-cost { color: var(--amber); }
.rank-cost .per { font-size: 0.66rem; font-weight: 500; color: var(--muted); display: block; }
.rank-track { height: 10px; border-radius: 5px; background: var(--surface-2); margin-top: 12px; overflow: hidden; }
.rank-fill { height: 100%; border-radius: 5px; background: var(--line-strong); }
.rank-card.best .rank-fill { background: var(--grad-brand); }
.rank-foot { display: flex; justify-content: space-between; font-size: 0.74rem; color: var(--muted); margin-top: 6px; }
.rank-foot .delta { color: var(--warn); font-weight: 600; }
.rank-foot .delta.best { color: var(--ice); }
#cmpRecCard { border-color: rgba(251, 146, 60, 0.4); }
#cmpRec { font-size: 0.88rem; line-height: 1.55; }

/* ---------- sheets ---------- */
.sheet {
  position: fixed; inset: 0; z-index: 60;
  background: rgba(2, 6, 18, 0.65);
  display: flex; align-items: flex-end; justify-content: center;
}
.sheet-card {
  background: var(--surface);
  border: 1px solid var(--line);
  border-radius: 22px 22px 0 0;
  padding: 10px 20px calc(20px + env(safe-area-inset-bottom));
  width: 100%; max-width: 620px;
  max-height: 88dvh; overflow-y: auto;
  animation: sheet-up 0.22s ease;
}
@keyframes sheet-up { from { transform: translateY(40px); opacity: 0.4; } to { transform: none; opacity: 1; } }
.sheet-grab { width: 42px; height: 4px; border-radius: 2px; background: var(--line-strong); margin: 4px auto 14px; }
.sheet-card h2 { font-size: 1.05rem; margin-bottom: 4px; }
.sheet-actions { display: flex; gap: 10px; margin-top: 18px; }
.sheet-actions button { flex: 1; }

.est-preview {
  margin-top: 14px; padding: 12px 14px;
  background: var(--flame-soft); border: 1px solid rgba(251, 146, 60, 0.45);
  border-radius: var(--radius-sm); font-size: 0.88rem;
}
.est-preview b { color: var(--flame); font-size: 1.05rem; }

/* segmented control */
.seg { display: flex; background: var(--surface-2); border: 1px solid var(--line); border-radius: 10px; padding: 3px; gap: 3px; }
.seg-btn {
  flex: 1; border: none; background: none; color: var(--muted);
  font-size: 0.82rem; font-weight: 650; padding: 9px 4px; border-radius: 8px;
}
.seg-btn.active { background: var(--ice); color: #06263c; }

/* ---------- toast ---------- */
.toast {
  position: fixed; left: 16px; right: 16px;
  bottom: calc(var(--tabbar-h) + env(safe-area-inset-bottom) + 14px);
  z-index: 80;
  max-width: 480px; margin: 0 auto;
  background: #2c1520; border: 1px solid var(--bad); color: #ffdada;
  border-radius: 12px; padding: 12px 16px;
  font-size: 0.86rem; text-align: center;
  box-shadow: var(--shadow);
  animation: sheet-up 0.2s ease;
}
.toast.info { background: #13233c; border-color: var(--ice); color: #d9effb; }

[hidden] { display: none !important; }

/* ---------- print report ---------- */
#report { display: none; }
@media print {
  body { background: #fff; color: #111; padding: 0; }
  body > *:not(#report) { display: none !important; }
  #report { display: block; font: 12px/1.5 system-ui, sans-serif; color: #111; }
  #report h1 { font-size: 20px; margin: 0 0 2px; }
  #report .rep-sub { color: #555; margin: 0 0 14px; font-size: 11px; }
  #report h2 { font-size: 14px; margin: 18px 0 6px; border-bottom: 2px solid #111; padding-bottom: 3px; }
  #report table { width: 100%; border-collapse: collapse; font-size: 11px; }
  #report th, #report td { border-bottom: 1px solid #ccc; padding: 5px 6px; text-align: right; color: #111; }
  #report th:first-child, #report td:first-child { text-align: left; }
  #report .rep-best td { font-weight: 700; }
  #report .rep-hero { font-size: 15px; margin: 6px 0; }
  #report .rep-hero b { font-size: 22px; }
  #report img { max-width: 100%; margin-top: 6px; }
  #report .rep-note { color: #555; font-size: 10px; margin-top: 14px; }
}

/* ---------- larger screens ---------- */
@media (min-width: 700px) {
  main { padding-top: 12px; }
  .card, .hero { padding: 22px; }
}