*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  min-height: 100vh;
  padding: var(--spacing-lg) var(--spacing-md);

  font-family: "Acumin Pro", system-ui, -apple-system, BlinkMacSystemFont,
    "Helvetica Neue", Arial, sans-serif;
  line-height: var(--line-height);

  display: flex;
  align-items: center;
  justify-content: center;

  background: var(--color-bg);
  color: var(--color-text);
}

:root {
  --font-size-base: 1rem;
  --font-size-h1: 2.25rem;

  --scale-golden: 1.618;
  --base-spacing: 1rem;
  --spacing-sm: calc(var(--base-spacing) / var(--scale-golden));
  --spacing-md: var(--base-spacing);
  --spacing-lg: calc(var(--base-spacing) * var(--scale-golden));
  --spacing-xl: calc(var(--spacing-lg) * var(--scale-golden));

  --container-max-width: 52ch;
  --container-narrow-max-width: 52ch;

  --color-bg: #f8f5f2;
  --color-text: #111;
  --color-heading: #111;
  --color-link: #0a84ff;
  --color-link-hover: #0066cc;
  --color-muted: rgba(17, 17, 17, 0.65);

  --transition-duration-base: 0.3s;
  --transition-duration-fast: 0.2s;
  --transition-timing: ease;
  --line-height: 1.7;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1a1a1a;
    --color-text: #e0e0e0;
    --color-heading: #fff;
    --color-link: #66aaff;
    --color-link-hover: #aaccff;
    --color-muted: rgba(255, 255, 255, 0.65);
  }
}

.header h1 {
  font-size: var(--font-size-h1);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  color: var(--color-heading);
  margin: 0 0 var(--spacing-lg) 0;
}

.header .error-title {
  color: #ffb300;
}

.visually-hidden {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0 0 0 0);
  border: 0;
}

.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin: 0 auto;
  animation: fade-in 0.6s var(--transition-timing) 0.1s both;
}

@media (max-width: 639px) {
  .container { max-width: var(--container-narrow-max-width); }
  body {
    padding: 0 var(--spacing-md);
  }
}

.text {
  font-size: var(--font-size-base);
}

.text p + p { margin-top: var(--spacing-lg); }

.text a {
  font-weight: 500;
  text-decoration: none;
  color: var(--color-link);
  border-bottom: 1px solid transparent;
  transition: color var(--transition-duration-fast) var(--transition-timing),
    border-color var(--transition-duration-fast) var(--transition-timing);
}

.text a:hover,
.text a:focus-visible {
  color: var(--color-link-hover);
  border-color: currentColor;
}

:focus-visible {
  outline: 2px dashed var(--color-link);
  outline-offset: 2px;
}

.skip-link {
  position: absolute;
  left: 0.5rem;
  top: 0;
  background: var(--color-link);
  color: #fff;
  padding: 0.5rem 0.75rem;
  border-radius: 0.25rem;

  /* Hide visually by default */
  clip: rect(0 0 0 0);
  width: 1px;
  height: 1px;
  overflow: hidden;
  white-space: nowrap;
}

.skip-link:focus {
  clip: auto;
  width: auto;
  height: auto;
  overflow: visible;
  white-space: normal;
  z-index: 1000;
}

.site-footer {
  margin-top: var(--spacing-xl);
  text-align: center;
  color: var(--color-muted);
  font-size: 0.95em;
  letter-spacing: 0.01em;
}

@keyframes fade-in {
  from {
    opacity: 0;
    transform: translateY(4px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}