/* Colours follow the app's Palette.xaml and Tokens.xaml */
:root,
[data-bs-theme="light"] {
  --cav-accent: #0067c0;
  --cav-accent-soft: #eef5fc;
  --cav-doctor: #0067c0;
  --cav-patient: #7a4ddb;
  --cav-device: #0f7b3f;
  --cav-caution: #b54708;
  --cav-surface: #ffffff;
  --cav-surface-alt: #f4f6f9;
  --cav-border: #e1e5ea;
  --bs-primary: #0067c0;
  --bs-primary-rgb: 0, 103, 192;
  --bs-link-color: #0067c0;
  --bs-link-color-rgb: 0, 103, 192;
  --bs-link-hover-color: #00539c;
  --bs-link-hover-color-rgb: 0, 83, 156;
  --bs-body-bg: #ffffff;
}

[data-bs-theme="dark"] {
  --cav-accent: #4ca0e0;
  --cav-accent-soft: #14273a;
  --cav-doctor: #4ca0e0;
  --cav-patient: #a98bea;
  --cav-device: #3fb56b;
  --cav-caution: #e0913a;
  --cav-surface: #202020;
  --cav-surface-alt: #1a1a1a;
  --cav-border: #333333;
  --bs-primary: #4ca0e0;
  --bs-primary-rgb: 76, 160, 224;
  --bs-link-color: #6db3e8;
  --bs-link-color-rgb: 109, 179, 232;
  --bs-link-hover-color: #9ccbf0;
  --bs-link-hover-color-rgb: 156, 203, 240;
  --bs-body-bg: #202020;
}

body {
  font-family: "Segoe UI Variable Text", "Segoe UI", system-ui, -apple-system, Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bs-body-bg);
}

h1, h2, h3, .display-5 { letter-spacing: -0.01em; }

section[id], header[id] { scroll-margin-top: 4.5rem; }

.btn-primary {
  --bs-btn-bg: var(--cav-accent);
  --bs-btn-border-color: var(--cav-accent);
  --bs-btn-hover-bg: #00539c;
  --bs-btn-hover-border-color: #00539c;
  --bs-btn-active-bg: #004a8a;
  --bs-btn-active-border-color: #004a8a;
}
[data-bs-theme="dark"] .btn-primary {
  --bs-btn-color: #0b1a26;
  --bs-btn-hover-color: #0b1a26;
  --bs-btn-active-color: #0b1a26;
  --bs-btn-hover-bg: #6db3e8;
  --bs-btn-hover-border-color: #6db3e8;
  --bs-btn-active-bg: #8cc3ec;
  --bs-btn-active-border-color: #8cc3ec;
}

/* Navigation */
.site-nav {
  background: color-mix(in srgb, var(--bs-body-bg) 88%, transparent);
  backdrop-filter: saturate(160%) blur(10px);
  border-bottom: 1px solid var(--cav-border);
}
.site-nav .nav-link { color: var(--bs-body-color); }
.site-nav .nav-link:hover { color: var(--cav-accent); }

.theme-toggle { width: 2.25rem; }
[data-bs-theme="light"] [data-theme-icon="dark"],
[data-bs-theme="dark"] [data-theme-icon="light"] { display: none; }

/* Hero */
.hero {
  background:
    radial-gradient(60rem 30rem at 85% -10%, var(--cav-accent-soft), transparent 70%),
    var(--bs-body-bg);
}

/* Screenshots */
.shot {
  border-radius: 0.6rem;
  overflow: hidden;
  border: 1px solid var(--cav-border);
  box-shadow: 0 1rem 2.5rem rgba(0, 0, 0, 0.08);
  background: var(--cav-surface);
}
[data-bs-theme="dark"] .shot { box-shadow: 0 1rem 2.5rem rgba(0, 0, 0, 0.45); }
.shot img { display: block; width: 100%; height: auto; }
.shot-link { display: block; transition: transform 0.15s ease; }
.shot-link:hover { transform: translateY(-2px); }
.shot-link:focus-visible { outline: 3px solid var(--cav-accent); outline-offset: 4px; border-radius: 0.6rem; }

[data-bs-theme="light"] .theme-img-dark,
[data-bs-theme="dark"] .theme-img-light { display: none !important; }

/* Sections */
.section-alt { background: var(--cav-surface-alt); }

.feature {
  background: var(--cav-surface);
  border: 1px solid var(--cav-border);
  border-radius: 0.75rem;
  padding: 1.5rem;
}

.who-doctor { color: var(--cav-doctor); font-weight: 600; }
.who-patient { color: var(--cav-patient); font-weight: 600; }

/* How it works flow */
.flow { display: flex; align-items: stretch; gap: 0.75rem; }
.flow-step { flex: 1; text-align: center; padding: 3.25rem 0.75rem 1.5rem; }
.flow-auto .flow-step { padding-top: 1rem; }
.flow-icon {
  width: 4rem; height: 4rem;
  margin: 0 auto 1.1rem;
  display: grid; place-items: center;
  border-radius: 50%;
  font-size: 1.6rem;
  background: var(--cav-accent);
  color: #fff;
  box-shadow: 0 0 0 6px var(--cav-accent-soft);
}
[data-bs-theme="dark"] .flow-icon { color: #0b1a26; }
.flow-auto .flow-icon {
  background: var(--bs-body-bg);
  color: var(--cav-accent);
  box-shadow: inset 0 0 0 2px var(--cav-accent);
}
.flow-arrow {
  align-self: flex-start;
  margin-top: 4.15rem;
  color: var(--bs-secondary-color);
  font-size: 1.4rem;
}
.flow-auto { flex: 3.3; display: flex; flex-direction: column; }
.flow-auto-inner {
  position: relative;
  flex: 1;
  display: flex;
  flex-direction: column;
  border-radius: 1.25rem;
  background: var(--cav-accent-soft);
}
.flow-auto-inner::before {
  content: "";
  position: absolute;
  inset: 0;
  padding: 2px;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--cav-accent), var(--cav-patient), var(--cav-accent));
  background-size: 200% 100%;
  animation: flow-border 6s linear infinite;
  -webkit-mask: linear-gradient(#000 0 0) content-box, linear-gradient(#000 0 0);
  -webkit-mask-composite: xor;
  mask: linear-gradient(#000 0 0) content-box exclude, linear-gradient(#000 0 0);
  pointer-events: none;
}
.flow-auto-label {
  text-align: center;
  padding-top: 1rem;
  color: var(--cav-accent);
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}
.flow-auto-steps { display: flex; gap: 0.75rem; flex: 1; padding-bottom: 0.5rem; }
.flow-auto-steps .flow-arrow { margin-top: 1.95rem; }
@keyframes flow-border { to { background-position: 200% 0; } }
@media (prefers-reduced-motion: reduce) { .flow-auto-inner::before { animation: none; } }
@media (max-width: 991.98px) {
  .flow, .flow-auto-steps { flex-direction: column; align-items: stretch; }
  .flow-arrow, .flow-auto-steps .flow-arrow { align-self: center; margin: 0; transform: rotate(90deg); }
  .flow-step, .flow-auto .flow-step { padding: 1rem 0.75rem; }
}

.feature-icon {
  font-size: 1.5rem;
  color: var(--cav-accent);
  display: inline-block;
  margin-bottom: 0.75rem;
}

.stat-value {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.1;
  color: var(--bs-body-color);
  margin-bottom: 0.5rem;
}
.stat-label { font-size: 0.95rem; line-height: 1.5; min-height: 3em; color: var(--bs-secondary-color); }

.models-table { --bs-table-bg: transparent; }
.models-table td:last-child, .models-table th:last-child { white-space: nowrap; }

.site-footer {
  border-top: 1px solid var(--cav-border);
  color: var(--bs-secondary-color);
}

#lightbox .modal-content { background: var(--cav-surface); }

/* UCL mark */
.footer-logo img, .brand-ucl { width: auto; display: block; }
.brand-divider { width: 1px; height: 1.25rem; margin: 0 0.75rem; background: var(--cav-border); }
[data-bs-theme="dark"] .brand-divider { background: #555; }

/* Hero screenshot: cross-fade and zoom */
/* Wider than the page container so the screenshot is readable */
@media (min-width: 1400px) { .hero > .container { max-width: 1560px; } }
.hero-stack { display: grid; position: relative; cursor: zoom-in; }
.hero-stack:focus-visible { outline: 3px solid var(--cav-accent); outline-offset: 4px; }
.hero-zoom {
  position: absolute;
  z-index: 1;
  right: 0.75rem;
  bottom: 0.75rem;
  display: grid;
  place-items: center;
  width: 2.25rem;
  height: 2.25rem;
  border-radius: 999px;
  background: rgba(0, 0, 0, 0.55);
  color: #fff;
  font-size: 0.95rem;
  opacity: 0.8;
  transition: opacity 0.15s ease;
}
.hero-stack:hover .hero-zoom { opacity: 1; }
/* Wide enough to read the app's text */
#lightbox .modal-xl { --bs-modal-width: min(84vw, 1600px); }
.hero-stack .hero-slide {
  grid-area: 1 / 1;
  opacity: 0;
  transition: opacity 0.8s ease;
}
.hero-stack .hero-slide.is-active { opacity: 1; }
.hero-switch { display: flex; justify-content: center; gap: 0.5rem; }
.hero-theme { justify-content: flex-end; }
.hero-switch button {
  border: 1px solid var(--cav-border);
  background: transparent;
  color: var(--bs-secondary-color);
  border-radius: 999px;
  padding: 0.25rem 0.85rem;
  font-size: 0.85rem;
}
.hero-switch button.is-active {
  color: var(--cav-accent);
  border-color: var(--cav-accent);
  background: var(--cav-accent-soft);
}
@media (prefers-reduced-motion: reduce) { .hero-stack .hero-slide { transition: none; } }