:root {
  color-scheme: dark;
  --bg-start: #07152f;
  --bg-end: #1565c0;
  --panel: rgba(8, 27, 58, 0.82);
  --panel-border: rgba(255, 255, 255, 0.16);
  --text: #f7fbff;
  --muted: #bfd2ea;
  --accent: #76c7ff;
  --button: #ffffff;
  --button-text: #0d47a1;
  --success: #5de29b;
  --warning: #ffd166;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-width: 320px;
  min-height: 100vh;
  font-family:
    Inter,
    ui-sans-serif,
    system-ui,
    -apple-system,
    BlinkMacSystemFont,
    "Segoe UI",
    sans-serif;
  color: var(--text);
  background:
    radial-gradient(circle at top, rgba(118, 199, 255, 0.3), transparent 34rem),
    linear-gradient(145deg, var(--bg-start), var(--bg-end));
}

body.theme-light {
  color-scheme: light;
  --bg-start: #eaf6ff;
  --bg-end: #8bc7ff;
  --panel: rgba(255, 255, 255, 0.88);
  --panel-border: rgba(13, 71, 161, 0.2);
  --text: #0b2347;
  --muted: #48627f;
}

.shell {
  width: min(100% - 2rem, 560px);
  margin: 0 auto;
  padding: 2rem 0;
}

.demo-banner {
  margin: 0 0 1rem;
  padding: 0.85rem 1rem;
  color: #2c2100;
  background: var(--warning);
  border-radius: 0.85rem;
  font-size: 0.9rem;
  font-weight: 700;
  line-height: 1.45;
  text-align: center;
}

.panel {
  padding: clamp(1.4rem, 5vw, 2.4rem);
  background: var(--panel);
  border: 1px solid var(--panel-border);
  border-radius: 1.5rem;
  box-shadow: 0 24px 70px rgba(0, 0, 0, 0.28);
  backdrop-filter: blur(18px);
}

.logo {
  font-size: 3.5rem;
  text-align: center;
}

.eyebrow {
  margin: 0.75rem 0 0;
  color: var(--accent);
  font-size: 0.78rem;
  font-weight: 800;
  letter-spacing: 0.13em;
  text-align: center;
  text-transform: uppercase;
}

h1 {
  margin: 0.35rem 0 0;
  font-size: clamp(2rem, 8vw, 3rem);
  line-height: 1.05;
  text-align: center;
}

.intro {
  margin: 1rem auto 1.5rem;
  max-width: 42ch;
  color: var(--muted);
  line-height: 1.6;
  text-align: center;
}

.status {
  display: flex;
  align-items: center;
  gap: 0.85rem;
  margin: 1.5rem 0;
  padding: 1rem;
  background: rgba(0, 0, 0, 0.18);
  border: 1px solid var(--panel-border);
  border-radius: 1rem;
}

.status__dot {
  width: 0.85rem;
  height: 0.85rem;
  flex: 0 0 auto;
  background: #ff6b6b;
  border-radius: 999px;
}

.status--on .status__dot {
  background: var(--success);
  box-shadow: 0 0 0 0.35rem rgba(93, 226, 155, 0.15);
}

.status strong,
.status span {
  display: block;
}

.status span {
  margin-top: 0.2rem;
  color: var(--muted);
  font-size: 0.88rem;
}

.details {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
  margin: 0 0 1.5rem;
}

.details div,
.result {
  padding: 1rem;
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid var(--panel-border);
  border-radius: 0.9rem;
}

dt {
  color: var(--muted);
  font-size: 0.75rem;
  text-transform: uppercase;
}

dd {
  margin: 0.25rem 0 0;
  font-weight: 700;
}

.actions {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}

.button,
.choice-grid button,
.nav-grid a {
  display: inline-flex;
  min-height: 3rem;
  align-items: center;
  justify-content: center;
  padding: 0.75rem 1rem;
  color: var(--button-text);
  background: var(--button);
  border: 0;
  border-radius: 0.85rem;
  font: inherit;
  font-weight: 800;
  text-align: center;
  text-decoration: none;
  cursor: pointer;
  transition:
    transform 150ms ease,
    opacity 150ms ease;
}

.button:hover,
.choice-grid button:hover,
.nav-grid a:hover {
  transform: translateY(-2px);
}

.button:focus-visible,
.choice-grid button:focus-visible,
.nav-grid a:focus-visible,
input:focus-visible {
  outline: 3px solid var(--warning);
  outline-offset: 3px;
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.45;
  transform: none;
}

.button--primary {
  color: #072650;
  background: var(--accent);
}

.button--link {
  width: 100%;
  margin-top: 1rem;
}

.nav-grid,
.choice-grid {
  display: grid;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.nav-grid {
  grid-template-columns: repeat(3, 1fr);
}

.nav-grid a {
  padding: 0.8rem 0.5rem;
  font-size: 0.82rem;
}

.choice-grid {
  grid-template-columns: repeat(2, 1fr);
}

.choice-grid button[aria-pressed="true"] {
  color: #072650;
  background: var(--accent);
  box-shadow: 0 0 0 3px rgba(118, 199, 255, 0.28);
}

.setting-list {
  display: grid;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.setting-list label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem;
  background: rgba(255, 255, 255, 0.07);
  border: 1px solid var(--panel-border);
  border-radius: 0.9rem;
}

.setting-list strong,
.setting-list small {
  display: block;
}

.setting-list small {
  margin-top: 0.25rem;
  color: var(--muted);
  line-height: 1.4;
}

.setting-list input {
  width: 1.35rem;
  height: 1.35rem;
  flex: 0 0 auto;
  accent-color: #42a5f5;
}

.notice {
  min-height: 1.4rem;
  margin: 1rem 0 0;
  color: var(--muted);
  font-size: 0.9rem;
  text-align: center;
}

.result {
  min-height: 7.5rem;
  margin: 1.5rem 0 1rem;
  color: var(--muted);
  line-height: 1.8;
  text-align: center;
}

@media (max-width: 480px) {
  .nav-grid {
    grid-template-columns: 1fr;
  }

  .details,
  .actions,
  .choice-grid {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    transition: none !important;
  }
}