:root {
  color-scheme: dark;
  --kai-bg: #000000;
  --kai-surface: #1c1c1e;
  --kai-surface-raised: #242428;
  --kai-surface-input: #323238;
  --kai-surface-muted: #2a2a2e;
  --kai-border: rgba(255, 255, 255, 0.10);
  --kai-border-strong: rgba(255, 255, 255, 0.18);
  --kai-text: #ffffff;
  --kai-text-muted: #a1a1aa;
  --kai-text-subtle: #71717a;
  --kai-accent: #ff3864;
  --kai-accent-pressed: #e72f58;
  --kai-accent-soft: rgba(255, 56, 100, 0.16);
  --kai-success: #30d158;
  --kai-success-soft: rgba(48, 209, 88, 0.16);
  --kai-warning: #ff9f0a;
  --kai-warning-soft: rgba(255, 159, 10, 0.16);
  --kai-error: #ff453a;
  --kai-error-soft: rgba(255, 69, 58, 0.16);
  --kai-info: #64d2ff;
  --kai-info-soft: rgba(100, 210, 255, 0.16);
  --kai-font: -apple-system, BlinkMacSystemFont, "SF Pro Display", "Hiragino Sans", "Noto Sans JP", "Yu Gothic", sans-serif;
  --kai-weight-regular: 400;
  --kai-weight-medium: 500;
  --kai-weight-semibold: 600;
  --kai-weight-bold: 700;
  --kai-weight-heavy: 800;
  --kai-radius-sm: 10px;
  --kai-radius-md: 14px;
  --kai-radius-lg: 18px;
  --kai-radius-xl: 24px;
  --kai-radius-pill: 999px;
  --kai-shadow-card: 0 18px 50px rgba(0, 0, 0, 0.30);
  --kai-shadow-floating: 0 20px 70px rgba(0, 0, 0, 0.48);
  --kai-bottom-nav-height: 82px;
}

* {
  box-sizing: border-box;
}

html {
  min-height: 100%;
  background: var(--kai-bg);
  color: var(--kai-text);
  font-family: var(--kai-font);
  -webkit-text-size-adjust: 100%;
}

body {
  margin: 0;
  min-height: 100vh;
  background: var(--kai-bg);
  color: var(--kai-text);
  font-family: var(--kai-font);
}

button,
input,
select,
textarea {
  font: inherit;
}

button {
  cursor: pointer;
}

button:disabled {
  cursor: not-allowed;
  opacity: 0.52;
}

a {
  color: var(--kai-accent);
  text-decoration: none;
}

img {
  display: block;
  max-width: 100%;
}

.kai-app-shell {
  width: min(100%, 430px);
  min-height: 100vh;
  margin: 0 auto;
  padding: max(24px, env(safe-area-inset-top)) 20px calc(var(--kai-bottom-nav-height) + max(24px, env(safe-area-inset-bottom)));
  background: var(--kai-bg);
}

.kai-desktop-shell {
  width: min(100%, 1120px);
  min-height: 100vh;
  margin: 0 auto;
  padding: 40px 28px;
}

.kai-screen-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 28px;
}

.kai-screen-header h1 {
  margin: 0;
  font-size: clamp(34px, 10vw, 48px);
  line-height: 1;
  font-weight: var(--kai-weight-heavy);
  letter-spacing: 0;
}

.kai-screen-title {
  margin: 0;
  font-size: clamp(34px, 10vw, 48px);
  line-height: 1;
  font-weight: var(--kai-weight-heavy);
  letter-spacing: 0;
}

.kai-section-title {
  margin: 0 0 14px;
  color: var(--kai-text);
  font-size: 24px;
  line-height: 1.15;
  font-weight: var(--kai-weight-bold);
  letter-spacing: 0;
}

.kai-eyebrow {
  margin: 0 0 8px;
  color: var(--kai-text-subtle);
  font-size: 13px;
  font-weight: var(--kai-weight-semibold);
}

.kai-muted {
  color: var(--kai-text-muted);
}

.kai-subtle {
  color: var(--kai-text-subtle);
}

.kai-stack {
  display: grid;
  gap: 16px;
}

.kai-stack-lg {
  display: grid;
  gap: 24px;
}

@media (min-width: 780px) {
  .kai-app-shell {
    width: min(100%, 760px);
    padding-inline: 28px;
  }

  .kai-grid-2 {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 16px;
  }

  .kai-grid-3 {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 16px;
  }
}