:root {
  color-scheme: light dark;
  --bg: #f3f6f8;
  --surface: #ffffff;
  --surface-subtle: #f7f9fa;
  --text: #172026;
  --muted: #697880;
  --border: #dce4e8;
  --border-strong: #c8d3d8;
  --primary: #087d87;
  --primary-strong: #06656e;
  --primary-soft: #e5f4f4;
  --accent: #f5a524;
  --danger: #b4433c;
  --success: #16745e;
  --shadow: 0 10px 28px rgba(31, 52, 61, 0.07);
  --radius: 18px;
  font-family: Inter, "SF Pro Display", "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
  font-synthesis: none;
}

:root[data-theme="dark"] {
  --bg: #0d151b;
  --surface: #141f26;
  --surface-subtle: #19262e;
  --text: #edf4f5;
  --muted: #9aabb2;
  --border: #293841;
  --border-strong: #3a4a53;
  --primary: #55c7cc;
  --primary-strong: #7bd7db;
  --primary-soft: #18383d;
  --accent: #f4b453;
  --danger: #fa8178;
  --success: #75d6ba;
  --shadow: 0 12px 34px rgba(0, 0, 0, 0.22);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0d151b;
    --surface: #141f26;
    --surface-subtle: #19262e;
    --text: #edf4f5;
    --muted: #9aabb2;
    --border: #293841;
    --border-strong: #3a4a53;
    --primary: #55c7cc;
    --primary-strong: #7bd7db;
    --primary-soft: #18383d;
    --accent: #f4b453;
    --danger: #fa8178;
    --success: #75d6ba;
    --shadow: 0 12px 34px rgba(0, 0, 0, 0.22);
  }
}

* { box-sizing: border-box; }

html {
  min-width: 320px;
  min-height: 100%;
  background: var(--bg);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  background:
    radial-gradient(circle at 50% -120px, color-mix(in srgb, var(--primary) 12%, transparent), transparent 320px),
    var(--bg);
  color: var(--text);
  -webkit-font-smoothing: antialiased;
}

button, input { font: inherit; }
button { color: inherit; -webkit-tap-highlight-color: transparent; }
button:focus-visible, input:focus-visible { outline: 3px solid color-mix(in srgb, var(--primary) 28%, transparent); outline-offset: 2px; }
button, .chip { touch-action: manipulation; }

.app-shell {
  width: min(100%, 760px);
  margin: 0 auto;
  padding: env(safe-area-inset-top) 14px calc(22px + env(safe-area-inset-bottom));
}

.app-header {
  display: flex;
  align-items: center;
  gap: 12px;
  min-height: 80px;
  padding: 16px 4px 12px;
}

.brand-mark {
  display: grid;
  grid-template-columns: repeat(2, 8px);
  gap: 3px;
  flex: 0 0 auto;
  width: 34px;
  height: 34px;
  place-content: center;
  border-radius: 10px;
  background: var(--text);
}

.brand-mark span { width: 8px; height: 8px; border-radius: 2px; background: var(--primary); }
.brand-mark span:nth-child(2), .brand-mark span:nth-child(3) { opacity: 0.58; }
.brand-copy { min-width: 0; flex: 1; }
.brand-copy h1 { margin: 0; font-size: 20px; line-height: 1.2; letter-spacing: -0.02em; }
.brand-copy p { margin: 4px 0 0; color: var(--muted); font-size: 11px; letter-spacing: 0.13em; text-transform: uppercase; }

.icon-button {
  display: grid;
  width: 44px;
  height: 44px;
  place-items: center;
  border: 1px solid var(--border);
  border-radius: 13px;
  background: var(--surface);
  cursor: pointer;
}

.icon-button svg { width: 20px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.moon-icon { display: none; }
:root[data-theme="dark"] .sun-icon { display: none; }
:root[data-theme="dark"] .moon-icon { display: block; }
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) .sun-icon { display: none; }
  :root:not([data-theme="light"]) .moon-icon { display: block; }
}

main { display: grid; gap: 14px; }

.card {
  overflow: hidden;
  padding: 20px 16px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow);
}

.section-heading { display: flex; align-items: center; gap: 12px; margin-bottom: 22px; }
.step-number { color: var(--primary); font-size: 11px; font-weight: 800; letter-spacing: 0.1em; }
.section-heading h2 { margin: 0; font-size: 17px; line-height: 1.25; }
.section-heading p { margin: 3px 0 0; color: var(--muted); font-size: 12px; }

.field-group + .field-group { margin-top: 20px; }
.field-group > label, .module-header-row > label { display: block; margin-bottom: 9px; color: var(--muted); font-size: 13px; font-weight: 650; }

.ratio-inputs { display: grid; grid-template-columns: 1fr auto 1fr; align-items: center; gap: 12px; }
.ratio-inputs > span { color: var(--muted); font-size: 23px; font-weight: 700; }

input {
  width: 100%;
  height: 52px;
  padding: 0 14px;
  border: 1px solid var(--border-strong);
  border-radius: 12px;
  background: var(--surface-subtle);
  color: var(--text);
  font-size: 17px;
  font-weight: 700;
  appearance: textfield;
}

input::-webkit-inner-spin-button, input::-webkit-outer-spin-button { margin: 0; appearance: none; }
input:hover { border-color: color-mix(in srgb, var(--primary) 44%, var(--border)); }
input:focus { border-color: var(--primary); background: var(--surface); }

.quick-options { display: flex; gap: 8px; margin-top: 10px; overflow-x: auto; scrollbar-width: none; }
.quick-options::-webkit-scrollbar { display: none; }
.chip {
  flex: 0 0 auto;
  min-height: 44px;
  padding: 0 13px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--surface-subtle);
  color: var(--muted);
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
}
.chip.active { border-color: color-mix(in srgb, var(--primary) 35%, var(--border)); background: var(--primary-soft); color: var(--primary-strong); }

.input-with-unit { position: relative; }
.input-with-unit input { padding-right: 54px; }
.input-with-unit > span { position: absolute; top: 50%; right: 15px; translate: 0 -50%; color: var(--muted); font-size: 14px; font-weight: 700; pointer-events: none; }

.ideal-result { display: flex; flex-direction: column; gap: 12px; margin-top: 20px; padding: 16px; border: 1px solid color-mix(in srgb, var(--primary) 20%, var(--border)); border-radius: 14px; background: var(--primary-soft); }
.eyebrow { display: block; margin-bottom: 6px; color: var(--primary-strong); font-size: 11px; font-weight: 800; letter-spacing: 0.08em; text-transform: uppercase; }
.ideal-result strong { font-size: clamp(20px, 6vw, 27px); letter-spacing: -0.035em; white-space: nowrap; }
.dimension-pair { display: flex; gap: 18px; color: var(--muted); font-size: 12px; }
.dimension-pair b { margin-left: 3px; color: var(--text); }

.module-header-row { display: flex; align-items: center; justify-content: space-between; margin-bottom: 9px; }
.module-header-row > label { margin: 0; }
.segmented-control { display: flex; padding: 3px; border-radius: 10px; background: var(--surface-subtle); box-shadow: inset 0 0 0 1px var(--border); }
.segmented-control button { min-width: 49px; min-height: 40px; padding: 0 12px; border: 0; border-radius: 8px; background: transparent; color: var(--muted); font-size: 12px; font-weight: 800; cursor: pointer; }
.segmented-control button.active { background: var(--surface); color: var(--primary-strong); box-shadow: 0 2px 7px rgba(20, 38, 46, 0.1); }
.module-inputs { display: grid; grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr); align-items: end; gap: 9px; }
.module-inputs label { display: block; margin: 0 0 7px 2px; color: var(--muted); font-size: 11px; font-weight: 650; }
.module-inputs .times { align-self: center; margin-top: 20px; color: var(--muted); font-size: 18px; }
.compact input { padding-right: 43px; }
.compact > span { right: 11px; font-size: 12px; }
.module-presets { padding-bottom: 2px; }

.primary-button, .secondary-button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 9px;
  width: 100%;
  min-height: 50px;
  padding: 0 16px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 800;
  cursor: pointer;
}
.primary-button { border: 1px solid var(--primary-strong); background: var(--primary-strong); color: #fff; box-shadow: 0 7px 16px color-mix(in srgb, var(--primary) 24%, transparent); }
:root[data-theme="dark"] .primary-button { color: #071d20; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) .primary-button { color: #071d20; } }
.secondary-button { border: 1px solid var(--border-strong); background: var(--surface); color: var(--text); }
.primary-button:hover { filter: brightness(0.96); }
.secondary-button:hover { border-color: var(--primary); }
.primary-button svg, .secondary-button svg { width: 18px; height: 18px; fill: none; stroke: currentColor; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.save-button { margin-top: 16px; min-height: 46px; color: var(--primary-strong); }

.saved-section { margin-top: 18px; padding-top: 16px; border-top: 1px solid var(--border); }
.saved-label { margin-bottom: 9px; color: var(--muted); font-size: 12px; font-weight: 750; }
.saved-list { display: grid; gap: 8px; }
.saved-item { display: flex; align-items: stretch; min-height: 44px; border: 1px solid var(--border); border-radius: 10px; background: var(--surface-subtle); }
.saved-item button { border: 0; background: transparent; cursor: pointer; }
.saved-value { flex: 1; padding: 0 12px; text-align: left; font-size: 13px; font-weight: 700; }
.delete-saved { display: grid; width: 44px; min-height: 44px; place-items: center; color: var(--muted); }
.delete-saved svg { width: 17px; fill: none; stroke: currentColor; stroke-width: 1.7; stroke-linecap: round; stroke-linejoin: round; }

.result-card { position: relative; border-color: color-mix(in srgb, var(--primary) 28%, var(--border)); }
.result-card::before { position: absolute; inset: 0 0 auto; height: 3px; background: var(--primary); content: ""; }
.result-heading { align-items: flex-start; }
.result-heading > div { flex: 1; }
.status-badge { flex: 0 0 auto; padding: 6px 9px; border-radius: 999px; background: var(--primary-soft); color: var(--primary-strong); font-size: 10px; font-weight: 800; }
.primary-result { padding: 20px 14px; border-radius: 14px; background: var(--surface-subtle); text-align: center; }
.primary-result > div { display: flex; align-items: baseline; justify-content: center; gap: 8px; }
.primary-result strong { font-size: clamp(42px, 13vw, 62px); line-height: 1; letter-spacing: -0.055em; }
.primary-result > div > span { color: var(--muted); font-size: 15px; font-weight: 700; }

.metrics-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 8px; margin-top: 10px; }
.metric { min-width: 0; padding: 13px 9px; border: 1px solid var(--border); border-radius: 11px; background: var(--surface); text-align: center; }
.metric span { display: block; margin-bottom: 5px; color: var(--muted); font-size: 10px; }
.metric strong { font-size: 14px; white-space: nowrap; }
.metric.accent { border-color: color-mix(in srgb, var(--accent) 35%, var(--border)); background: color-mix(in srgb, var(--accent) 8%, var(--surface)); }
.metric.accent strong { color: color-mix(in srgb, var(--accent) 72%, var(--text)); }

.details-list { margin: 18px 0 0; border-top: 1px solid var(--border); }
.details-list > div { display: flex; align-items: center; justify-content: space-between; min-height: 50px; gap: 12px; border-bottom: 1px solid var(--border); }
.details-list > div > span { color: var(--muted); font-size: 12px; }
.details-list > div > strong { text-align: right; font-size: 14px; }
.details-list small { margin-left: 8px; color: var(--primary-strong); font-size: 12px; }
.action-stack { display: grid; gap: 9px; margin-top: 18px; }
.chevron { margin-left: auto; transition: rotate 180ms ease; }
[aria-expanded="true"] .chevron { rotate: 180deg; }

.validation-message { padding: 18px; border: 1px solid color-mix(in srgb, var(--danger) 30%, var(--border)); border-radius: 12px; background: color-mix(in srgb, var(--danger) 8%, var(--surface)); color: var(--danger); font-size: 14px; font-weight: 700; text-align: center; }

.alternatives-panel { margin-top: 20px; padding-top: 19px; border-top: 1px solid var(--border); }
.alternatives-header { display: flex; align-items: baseline; justify-content: space-between; margin-bottom: 10px; }
.alternatives-header h3 { margin: 0; font-size: 14px; }
.alternatives-header > span { color: var(--muted); font-size: 10px; }
.alternatives-list { display: grid; gap: 9px; }
.alternative-item { padding: 13px; border: 1px solid var(--border); border-radius: 12px; background: var(--surface-subtle); }
.alternative-item.recommended { border-color: color-mix(in srgb, var(--primary) 45%, var(--border)); background: var(--primary-soft); }
.alternative-top { display: flex; align-items: center; justify-content: space-between; gap: 10px; }
.alternative-top > div { display: flex; align-items: baseline; gap: 7px; }
.alternative-top strong { font-size: 18px; }
.alternative-top > div > span { color: var(--muted); font-size: 10px; }
.alternative-status { flex: 0 0 auto; padding: 4px 7px; border-radius: 999px; font-size: 9px; font-weight: 800; }
.alternative-status.good { background: color-mix(in srgb, var(--success) 12%, transparent); color: var(--success); }
.alternative-status.small { background: color-mix(in srgb, var(--accent) 12%, transparent); color: color-mix(in srgb, var(--accent) 72%, var(--text)); }
.alternative-status.warning { background: color-mix(in srgb, var(--danger) 10%, transparent); color: var(--danger); }
.alternative-meta { display: grid; grid-template-columns: 1fr auto; gap: 5px 10px; margin-top: 9px; color: var(--muted); font-size: 10px; }
.alternative-meta strong { grid-column: 1 / -1; color: var(--text); font-size: 11px; }

footer { display: flex; align-items: center; justify-content: space-between; gap: 12px; padding: 20px 4px 6px; color: var(--muted); font-size: 9px; }
#connectionStatus { display: inline-flex; align-items: center; gap: 0; }
#connectionStatus i { width: 6px; height: 6px; margin-right: 6px; border-radius: 50%; background: var(--success); box-shadow: 0 0 0 3px color-mix(in srgb, var(--success) 10%, transparent); }
#connectionStatus.offline i { background: var(--accent); }

.toast { position: fixed; z-index: 10; left: 50%; bottom: calc(28px + env(safe-area-inset-bottom)); translate: -50% 18px; padding: 11px 17px; border-radius: 999px; background: var(--text); color: var(--surface); font-size: 13px; font-weight: 750; opacity: 0; pointer-events: none; transition: opacity 160ms ease, translate 160ms ease; box-shadow: 0 8px 24px rgba(0, 0, 0, 0.18); }
.toast.visible { translate: -50% 0; opacity: 1; }
[hidden] { display: none !important; }

@media (min-width: 560px) {
  .app-shell { padding-inline: 20px; }
  .card { padding: 24px; }
  .ideal-result { flex-direction: row; align-items: center; justify-content: space-between; }
  .dimension-pair { flex-direction: column; gap: 5px; text-align: right; }
  .action-stack { grid-template-columns: 1fr 1fr; }
}

@media (min-width: 820px) {
  .app-shell { width: min(100%, 1100px); }
  main { grid-template-columns: repeat(2, minmax(0, 1fr)); align-items: start; }
  .result-card { grid-column: 1 / -1; }
  #resultContent { display: grid; grid-template-columns: 0.9fr 1.1fr; gap: 0 28px; }
  .primary-result, .metrics-grid { grid-column: 1; }
  .details-list, .action-stack { grid-column: 2; }
  .details-list { grid-row: 1 / span 2; margin-top: 0; }
  .alternatives-panel { grid-column: 1 / -1; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { scroll-behavior: auto !important; transition-duration: 0.01ms !important; }
}