:root {
  color-scheme: light;
  --bg: #f6fbfd;
  --surface: #ffffff;
  --surface-2: #eef8fb;
  --text: #153241;
  --muted: #657987;
  --primary: #0b74d1;
  --primary-2: #18b7c9;
  --border: #d9e8ef;
  --shadow: 0 18px 45px rgba(31, 85, 116, 0.12);
  --danger: #c83256;
  --success: #0f8b62;
}

[data-theme="dark"] {
  color-scheme: dark;
  --bg: #0d1518;
  --surface: #142126;
  --surface-2: #193038;
  --text: #edf8fb;
  --muted: #a7bac3;
  --primary: #57a7ff;
  --primary-2: #31d2df;
  --border: #2f464f;
  --shadow: 0 18px 45px rgba(0, 0, 0, 0.34);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: Inter, ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--surface) 90%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border);
}
.nav {
  width: min(1160px, calc(100% - 32px));
  margin: 0 auto;
  min-height: 76px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}
.brand { display: flex; align-items: center; gap: 12px; }
.brand-mark {
  width: 38px; height: 38px; display: grid; place-items: center;
  border-radius: 8px; background: var(--primary); color: white; font-weight: 800;
}
.brand small { display: block; color: var(--muted); font-size: 0.78rem; }
.nav-links { display: flex; align-items: center; gap: 18px; color: var(--muted); }
.nav-links a:hover { color: var(--primary); }
.nav-toggle { display: none; }
.icon-button, .nav-toggle {
  border: 1px solid var(--border); background: var(--surface); color: var(--text);
  min-width: 42px; height: 42px; border-radius: 8px; cursor: pointer;
}

.hero {
  width: min(1160px, calc(100% - 32px));
  margin: 42px auto 36px;
  display: grid;
  grid-template-columns: 1.08fr 0.92fr;
  gap: 34px;
  align-items: center;
}
.hero h1, .page-head h1 { font-size: clamp(2.2rem, 6vw, 4.8rem); line-height: 1.02; margin: 10px 0 18px; }
.hero p, .page-head p { color: var(--muted); font-size: 1.12rem; max-width: 620px; }
.eyebrow { color: var(--primary); font-weight: 700; text-transform: uppercase; font-size: 0.78rem; letter-spacing: 0; }
.primary-button, .secondary-button {
  display: inline-flex; align-items: center; justify-content: center; gap: 8px;
  min-height: 44px; padding: 0 18px; border-radius: 8px; border: 1px solid transparent;
  font-weight: 700; cursor: pointer;
}
.primary-button { background: var(--primary); color: white; }
.secondary-button { background: var(--surface); color: var(--primary); border-color: var(--border); }
.hero-visual {
  min-height: 420px; border-radius: 8px; background: linear-gradient(135deg, var(--surface), var(--surface-2));
  box-shadow: var(--shadow); position: relative; display: grid; place-items: center; overflow: hidden;
}
.scan-panel {
  width: min(78%, 360px); aspect-ratio: 0.82; border: 1px solid var(--border); border-radius: 8px;
  background: radial-gradient(circle at 50% 22%, rgba(24,183,201,.22), transparent 22%), #10252c;
  position: relative; display: flex; align-items: center; justify-content: center; gap: 12px;
}
.lung-shape { width: 34%; height: 58%; border: 2px solid #9ee8f0; opacity: .85; }
.lung-shape.left { border-radius: 64% 36% 44% 56%; }
.lung-shape.right { border-radius: 36% 64% 56% 44%; }
.scan-panel span { position: absolute; left: 0; right: 0; top: 44%; height: 2px; background: var(--primary-2); box-shadow: 0 0 18px var(--primary-2); }
.signal-card {
  position: absolute; right: 28px; bottom: 28px; background: var(--surface); border: 1px solid var(--border);
  border-radius: 8px; padding: 18px 22px; box-shadow: var(--shadow); color: var(--muted);
}
.signal-card strong { color: var(--text); }

.container, .page-head, .analyze-layout, .result-hero {
  width: min(1160px, calc(100% - 32px));
  margin: 0 auto 34px;
}
.page-head { padding: 44px 0 10px; }
.stats-band {
  width: min(1160px, calc(100% - 32px));
  margin: 0 auto 48px;
  display: grid; grid-template-columns: repeat(4, 1fr); gap: 12px;
}
.stats-band div, .panel, .upload-card, .info-panel, .result-card, .class-grid article, .steps article {
  background: var(--surface); border: 1px solid var(--border); border-radius: 8px; box-shadow: var(--shadow);
}
.stats-band div { padding: 18px; }
.stats-band strong, .stats-band span { display: block; }
.stats-band span { color: var(--muted); }
.steps, .class-grid, .about-grid, .result-grid {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 16px;
}
.class-grid, .about-grid, .result-grid { grid-template-columns: repeat(2, 1fr); }
.research-panel { grid-column: 1 / -1; }
.research-panel a { color: var(--primary); font-weight: 700; overflow-wrap: anywhere; }
.reference-list { display: grid; gap: 12px; }
.steps article, .class-grid article, .panel { padding: 22px; }
.steps b { width: 32px; height: 32px; border-radius: 50%; display: grid; place-items: center; background: var(--surface-2); color: var(--primary); }
.disclaimer {
  background: var(--surface-2); border-left: 4px solid var(--primary-2); padding: 24px; border-radius: 8px;
}

.analyze-layout { display: grid; grid-template-columns: 1.45fr .55fr; gap: 20px; align-items: start; }
.upload-card, .info-panel { padding: 22px; }
.drop-zone {
  min-height: 360px; border: 2px dashed var(--border); border-radius: 8px;
  display: grid; place-items: center; text-align: center; padding: 24px; cursor: pointer; gap: 10px;
}
.drop-zone.dragover { border-color: var(--primary-2); background: var(--surface-2); }
.drop-zone input { position: absolute; opacity: 0; pointer-events: none; }
.upload-icon { font-size: 2.4rem; color: var(--primary); }
.drop-zone em, .drop-zone small { color: var(--muted); }
.preview-panel { display: grid; grid-template-columns: minmax(160px, 280px) 1fr; gap: 22px; align-items: center; }
.preview-panel img { width: 100%; aspect-ratio: 1; object-fit: contain; background: #0b1519; border-radius: 8px; }
.loading-panel { text-align: center; padding: 28px; }
.spinner { width: 46px; height: 46px; border: 4px solid var(--border); border-top-color: var(--primary); border-radius: 50%; margin: 0 auto 14px; animation: spin 1s linear infinite; }
@keyframes spin { to { transform: rotate(360deg); } }

.result-hero { padding-top: 34px; display: grid; grid-template-columns: .9fr 1.1fr; gap: 20px; align-items: stretch; }
.result-card { padding: 28px; }
.result-card h1 { margin: 8px 0; font-size: clamp(2rem, 4vw, 3.4rem); }
.confidence { font-size: 3rem; font-weight: 800; color: var(--primary); }
.confidence span { display: block; font-size: 1rem; color: var(--muted); }
.status { display: inline-block; padding: 8px 12px; border-radius: 999px; font-weight: 700; }
.status.normal { background: rgba(15,139,98,.14); color: var(--success); }
.status.pneumonia { background: rgba(200,50,86,.14); color: var(--danger); }
.image-compare { display: grid; grid-template-columns: repeat(2, 1fr); gap: 14px; }
.image-compare.single { grid-template-columns: 1fr; }
.image-compare figure { margin: 0; background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 12px; box-shadow: var(--shadow); }
.image-compare img { width: 100%; aspect-ratio: 1; object-fit: contain; background: #0b1519; border-radius: 8px; }
figcaption { color: var(--muted); margin-top: 8px; }
.prob-list { display: grid; gap: 12px; margin-top: 16px; }
.prob-list div { display: grid; grid-template-columns: 1fr auto; gap: 8px; align-items: center; }
.prob-list meter { grid-column: 1 / -1; width: 100%; height: 12px; }
.prob-list .top span, .prob-list .top b { color: var(--primary); }
.big-number { font-size: 3rem; margin: 0; font-weight: 800; color: var(--primary); }

.table-wrap { overflow-x: auto; background: var(--surface); border: 1px solid var(--border); border-radius: 8px; box-shadow: var(--shadow); }
table { width: 100%; border-collapse: collapse; min-width: 760px; }
th, td { text-align: left; padding: 14px 16px; border-bottom: 1px solid var(--border); }
th { color: var(--muted); font-size: .9rem; }
.actions { display: flex; align-items: center; gap: 10px; }
.actions a, .actions button { color: var(--primary); border: 0; background: transparent; font: inherit; cursor: pointer; padding: 0; }
.flash-wrap { width: min(1160px, calc(100% - 32px)); margin: 16px auto 0; }
.flash, .notice { padding: 14px 16px; border-radius: 8px; background: var(--surface-2); border: 1px solid var(--border); }
.error { color: var(--danger); }
.success { color: var(--success); }
.footer { width: min(1160px, calc(100% - 32px)); margin: 48px auto 22px; color: var(--muted); }

@media (max-width: 820px) {
  .nav { min-height: 68px; }
  .nav-toggle { display: inline-grid; place-items: center; }
  .nav-links {
    position: absolute; top: 68px; left: 16px; right: 16px; display: none; flex-direction: column;
    align-items: stretch; background: var(--surface); border: 1px solid var(--border); border-radius: 8px; padding: 16px;
  }
  .nav-links.open { display: flex; }
  .hero, .analyze-layout, .result-hero, .result-grid { grid-template-columns: 1fr; }
  .stats-band, .steps, .class-grid, .about-grid { grid-template-columns: 1fr; }
  .hero-visual { min-height: 320px; }
  .preview-panel, .image-compare { grid-template-columns: 1fr; }
  .confidence { font-size: 2.35rem; }
}