/* ============================================
   HOUSI — The Objective Grid (Swiss International)
   ============================================ */

/* --- Color Tokens --- */
:root {
  --primary: #000000;
  --on-primary: #ffffff;
  --primary-fixed: #c00100;
  --surface: #f9f9f9;
  --surface-container-low: #f3f3f3;
  --surface-container: #eeeeee;
  --surface-container-high: #e8e8e8;
  --surface-container-highest: #e2e2e2;
  --surface-container-lowest: #ffffff;
  --on-surface: #1b1b1b;
  --on-surface-variant: #444746;
  --outline: #747775;
  --outline-variant: #c6c6c6;
  --error: #ba1a1a;
  --error-container: #ffdad6;
  --success: #1a7a1a;
  --bg: #f9f9f9;

  /* --- Typography --- */
  --font: 'Inter', system-ui, -apple-system, sans-serif;

  /* Display */
  --display-lg: 3.5rem;
  --display-md: 2.5rem;
  --display-sm: 2rem;

  /* Headlines */
  --headline-lg: 2rem;
  --headline-md: 1.5rem;
  --headline-sm: 1.25rem;

  /* Body */
  --body-lg: 1rem;
  --body-md: 0.875rem;
  --body-sm: 0.8125rem;

  /* Labels */
  --label-lg: 0.875rem;
  --label-md: 0.75rem;
  --label-sm: 0.6875rem;

  /* --- Spacing Scale --- */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-8: 2rem;
  --space-10: 2.5rem;
  --space-12: 3.5rem;
  --space-16: 4.5rem;
  --space-20: 7rem;

  /* --- Layout --- */
  --container-max: 1120px;
  --container-pad: 2rem;

  /* --- Elevation --- */
  --shadow-ambient: 0 20px 40px rgba(27, 27, 27, 0.06);
  --shadow-glass: 0 1px 0 rgba(0, 0, 0, 0.04);

  /* --- Transitions --- */
  --dur: 0ms;
  --dur-fast: 120ms;
  --ease: linear;
}

/* --- Dark Mode --- */
:root.dark {
  --primary: #f5f5f5;
  --on-primary: #000000;
  --primary-fixed: #ffb3b1;
  --surface: #121212;
  --surface-container-low: #1c1c1e;
  --surface-container: #212123;
  --surface-container-high: #2b2b2d;
  --surface-container-highest: #363638;
  --surface-container-lowest: #0c0c0c;
  --on-surface: #e5e5e7;
  --on-surface-variant: #c4c7c5;
  --outline: #8e918f;
  --outline-variant: #444746;
  --error: #ffb4ab;
  --error-container: #93000a;
  --success: #6dd66d;
  --bg: #121212;
  --shadow-ambient: 0 20px 40px rgba(0, 0, 0, 0.3);
}

/* --- Reset --- */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font);
  font-size: var(--body-lg);
  color: var(--on-surface);
  background: var(--bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

a {
  color: var(--on-surface);
  text-decoration: none;
}

/* --- Layout --- */
.container {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad);
}

/* --- Buttons --- */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--label-lg);
  font-weight: 600;
  font-family: var(--font);
  letter-spacing: 0.02em;
  border: none;
  border-radius: 0;
  cursor: pointer;
  transition: background-color var(--dur-fast) var(--ease), color var(--dur-fast) var(--ease);
}

.btn-primary {
  background: var(--primary);
  color: var(--on-primary);
}

.btn-primary:hover {
  opacity: 0.85;
}

.btn-secondary {
  background: var(--surface-container-high);
  color: var(--on-surface);
}

.btn-secondary:hover {
  background: var(--surface-container-highest);
}

.btn-tertiary {
  background: none;
  color: var(--on-surface);
  font-weight: 700;
  padding: 0;
}

.btn-tertiary:hover {
  text-decoration: underline;
  text-decoration-thickness: 2px;
  text-underline-offset: 3px;
}

.btn-signal {
  background: var(--primary-fixed);
  color: var(--surface-container-lowest);
}

.btn-signal:hover {
  opacity: 0.85;
}

.btn:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

/* --- Inputs --- */
input[type="email"],
input[type="text"] {
  width: 100%;
  padding: var(--space-3) 0;
  font-size: var(--body-lg);
  font-family: var(--font);
  background: transparent;
  color: var(--on-surface);
  border: none;
  border-bottom: 1px solid var(--outline-variant);
  outline: none;
  transition: border-color var(--dur-fast) var(--ease);
}

input[type="email"]:focus,
input[type="text"]:focus {
  border-bottom-color: var(--on-surface);
}

input[type="email"]::placeholder,
input[type="text"]::placeholder {
  color: var(--outline);
}

input[type="email"]:disabled,
input[type="text"]:disabled {
  opacity: 0.4;
}

/* --- Section Label --- */
.section-label {
  display: block;
  font-size: var(--label-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--on-surface-variant);
  margin-bottom: var(--space-4);
}

.section-title {
  font-size: var(--headline-lg);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.15;
  color: var(--on-surface);
}

/* --- Theme Toggle --- */
.theme-toggle {
  position: fixed;
  bottom: var(--space-6);
  right: var(--space-6);
  width: 44px;
  height: 44px;
  display: grid;
  place-items: center;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: none;
  border-radius: 0;
  box-shadow: var(--shadow-glass);
  color: var(--on-surface);
  cursor: pointer;
  z-index: 100;
  transition: background-color var(--dur-fast) var(--ease);
}

:root.dark .theme-toggle {
  background: rgba(18, 18, 18, 0.95);
}

/* --- Navigation --- */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 50;
  background: rgba(255, 255, 255, 0.95);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  padding: var(--space-4) 0;
  box-shadow: var(--shadow-glass);
}

:root.dark .nav {
  background: rgba(18, 18, 18, 0.95);
}

.nav-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad);
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-size: 1.125rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  color: var(--on-surface);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-8);
}

.nav-links a {
  font-size: var(--label-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--on-surface-variant);
  transition: color var(--dur-fast) var(--ease);
}

.nav-links a:hover {
  color: var(--on-surface);
}

/* --- Hero --- */
.hero {
  background: var(--bg);
  padding: calc(var(--space-20) + 3rem) var(--container-pad) var(--space-16);
}

.hero-content {
  max-width: var(--container-max);
  margin: 0 auto;
  padding: 0 var(--container-pad);
}

.hero-label {
  display: block;
  margin-bottom: var(--space-6);
}

.hero-title {
  font-size: var(--display-lg);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.0;
  color: var(--on-surface);
  margin-bottom: var(--space-6);
  max-width: 14ch;
}

.hero-subtitle {
  font-size: var(--body-lg);
  color: var(--on-surface-variant);
  line-height: 1.75;
  max-width: 46ch;
  margin-bottom: var(--space-10);
}

.hero-signal {
  display: inline-block;
  color: var(--primary-fixed);
  font-weight: 700;
}

/* --- Features --- */
.features {
  padding: var(--space-16) var(--container-pad);
  background: var(--surface-container-low);
}

.features-header {
  margin-bottom: var(--space-12);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-1);
}

.feature-card {
  background: var(--surface-container-lowest);
  padding: var(--space-8);
  border-radius: 0;
}

.feature-icon {
  width: 40px;
  height: 40px;
  display: grid;
  place-items: center;
  margin-bottom: var(--space-6);
  color: var(--on-surface);
}

.feature-title {
  font-size: var(--headline-sm);
  font-weight: 700;
  letter-spacing: -0.01em;
  margin-bottom: var(--space-2);
  color: var(--on-surface);
}

.feature-desc {
  font-size: var(--body-md);
  color: var(--on-surface-variant);
  line-height: 1.7;
}

.feature-index {
  font-size: var(--label-sm);
  font-weight: 500;
  color: var(--outline);
  letter-spacing: 0.05em;
  margin-bottom: var(--space-4);
}

/* --- Gallery --- */
.gallery {
  padding: var(--space-16) var(--container-pad);
  background: var(--bg);
}

.gallery-header {
  margin-bottom: var(--space-12);
}

.gallery-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  grid-template-rows: auto auto;
  gap: var(--space-1);
}

.gallery-item {
  border-radius: 0;
  overflow: hidden;
  aspect-ratio: 3 / 2;
  background: var(--surface-container);
}

.gallery-item:first-child {
  grid-row: span 2;
  aspect-ratio: auto;
}

.gallery-item img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

/* --- Newsletter --- */
.newsletter {
  padding: var(--space-16) var(--container-pad);
  background: var(--surface-container);
}

.newsletter-inner {
  max-width: 480px;
}

.newsletter-desc {
  font-size: var(--body-lg);
  color: var(--on-surface-variant);
  max-width: 42ch;
  margin-bottom: var(--space-10);
  line-height: 1.75;
}

.newsletter-form {
  display: flex;
  gap: var(--space-6);
  align-items: flex-end;
}

.newsletter-input-wrap {
  flex: 1;
  position: relative;
}

.newsletter-btn-wrap {
  flex-shrink: 0;
  padding-bottom: 1px;
}

.newsletter-message {
  margin-top: var(--space-4);
  font-size: var(--body-md);
  font-weight: 500;
}

.newsletter-success {
  color: var(--success);
}

.newsletter-error {
  color: var(--error);
}

/* --- Footer --- */
.footer {
  padding: var(--space-8) var(--container-pad);
  background: var(--bg);
}

.footer-inner {
  max-width: var(--container-max);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.footer-brand {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: var(--body-md);
  font-weight: 700;
  color: var(--on-surface);
}

.footer-links {
  display: flex;
  gap: var(--space-6);
}

.footer-links a {
  font-size: var(--label-sm);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--on-surface-variant);
  transition: color var(--dur-fast) var(--ease);
}

.footer-links a:hover {
  color: var(--on-surface);
}

.footer-copy {
  font-size: var(--label-sm);
  color: var(--outline);
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .hero {
    padding: calc(var(--space-12) + 3rem) var(--container-pad) var(--space-12);
  }

  .hero-title {
    font-size: var(--display-md);
    max-width: 12ch;
  }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-1);
  }

  .gallery-grid {
    grid-template-columns: 1fr 1fr;
    grid-template-rows: auto;
  }

  .gallery-item:first-child {
    grid-row: span 1;
    aspect-ratio: 3 / 2;
  }

  .nav-links {
    gap: var(--space-4);
  }
}

@media (max-width: 480px) {
  :root {
    --container-pad: 1.25rem;
  }

  .hero {
    padding: calc(var(--space-10) + 3rem) var(--container-pad) var(--space-10);
  }

  .hero-title {
    font-size: 2.25rem;
  }

  .features-grid {
    grid-template-columns: 1fr;
  }

  .gallery-grid {
    grid-template-columns: 1fr;
  }

  .newsletter-form {
    flex-direction: column;
    align-items: stretch;
  }

  .newsletter-btn-wrap {
    padding-bottom: 0;
  }

  .features,
  .gallery,
  .newsletter {
    padding: var(--space-12) var(--container-pad);
  }

  .footer-inner {
    flex-direction: column;
    gap: var(--space-4);
    text-align: left;
    align-items: flex-start;
  }
}

/* --- Reduced Motion --- */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}