/*
 * main.css — Global styles
 *
 * Requirements: 13.1, 13.2, 13.3
 */

/* ============================================================
   Custom Properties
   ============================================================ */
:root {
  /* Brand colours */
  --color-black: #1a1a1a;
  --color-blue:  #2e5fa3;
  --color-gray:  #6b6b6b;
  --color-white: #ffffff;
  --color-light: #f5f5f5;

  /* Derived semantic colours */
  --color-blue-dark:  #244d8a;
  --color-blue-light: #3a72c0;
  --color-danger:     #c0392b;
  --color-danger-dark: #a93226;
  --color-success:    #27ae60;
  --color-border:     #d1d5db;
  --color-text:       var(--color-black);
  --color-text-muted: var(--color-gray);
  --color-bg:         var(--color-white);

  /* Typography */
  --font-sans:       'Inter', system-ui, sans-serif;
  --font-size-base:  1rem;
  --font-size-sm:    0.875rem;
  --font-size-lg:    1.125rem;
  --font-size-xl:    1.25rem;
  --font-size-2xl:   1.5rem;
  --font-size-3xl:   2rem;
  --font-size-4xl:   2.5rem;
  --line-height:     1.6;

  /* Spacing scale */
  --space-xs:  0.25rem;
  --space-sm:  0.5rem;
  --space-md:  1rem;
  --space-lg:  1.5rem;
  --space-xl:  2rem;
  --space-2xl: 3rem;
  --space-3xl: 4rem;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;

  /* Border radius */
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 12px;

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.1);
  --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.1);
}

/* ============================================================
   Dark Mode — Automatic based on system preference
   Respects user's OS dark mode, mobile dark mode, or time-based settings
   ============================================================ */
@media (prefers-color-scheme: dark) {
  :root {
    /* Dark mode color overrides - keep semantic meaning */
    --color-text:       #e5e5e5;
    --color-text-muted: #a0a0a0;
    --color-bg:         #121212;
    --color-light:      #1e1e1e;
    --color-border:     #3a3a3a;
    --color-gray:       #a0a0a0;
    
    /* Blue colors adjusted for dark mode */
    --color-blue:       #5b8fd8;
    --color-blue-dark:  #4a7bc4;
    --color-blue-light: #6fa3e6;
    
    /* Keep black and white as they are for nav/footer */
    /* --color-black and --color-white stay the same */
    
    /* Adjusted shadows for dark mode */
    --shadow-sm: 0 1px 3px rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 6px rgba(0, 0, 0, 0.6);
    --shadow-lg: 0 10px 15px rgba(0, 0, 0, 0.7);
  }

  /* Dark mode specific adjustments */
  body {
    background-color: #121212;
    color: #e5e5e5;
  }

  /* Headings in dark mode */
  h1, h2, h3, h4, h5, h6 {
    color: #e5e5e5;
  }

  /* Images slightly dimmed in dark mode for comfort */
  img:not(.hero__logo):not(.nav__logo img):not(.lightbox__img):not(.admin-nav__logo-link img) {
    opacity: 0.9;
  }

  /* Links in dark mode */
  a {
    color: #5b8fd8;
  }

  a:hover {
    color: #6fa3e6;
  }

  /* Buttons in dark mode */
  .btn--primary {
    background-color: #5b8fd8;
    border-color: #5b8fd8;
  }

  .btn--primary:hover {
    background-color: #4a7bc4;
    border-color: #4a7bc4;
  }

  .btn--secondary {
    background-color: #2a2a2a;
    border-color: #3a3a3a;
  }

  .btn--secondary:hover {
    background-color: #3a3a3a;
    border-color: #4a4a4a;
  }

  .btn--outline {
    border-color: #5b8fd8;
    color: #5b8fd8;
  }

  .btn--outline:hover {
    background-color: #5b8fd8;
    color: #121212;
  }
}

/* ============================================================
   CSS Reset
   ============================================================ */
*,
*::before,
*::after {
  box-sizing: border-box;
}

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

body,
h1, h2, h3, h4, h5, h6,
p, figure, blockquote, dl, dd,
ul, ol, li,
fieldset, legend,
pre, address {
  margin: 0;
  padding: 0;
}

ul,
ol {
  list-style: none;
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
}

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

p,
h1, h2, h3, h4, h5, h6 {
  overflow-wrap: break-word;
}

a {
  color: inherit;
  text-decoration: none;
}

/* ============================================================
   Base Typography
   ============================================================ */
body {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: var(--line-height);
  color: var(--color-text);
  background-color: var(--color-bg);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  transition: background-color 300ms ease, color 300ms ease;
}

h1, h2, h3, h4, h5, h6 {
  line-height: 1.2;
  font-weight: 700;
  color: var(--color-black);
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }
h4 { font-size: var(--font-size-lg); }

p {
  margin-bottom: var(--space-md);
}

p:last-child {
  margin-bottom: 0;
}

a:hover {
  text-decoration: underline;
}

/* ============================================================
   Utility Classes
   ============================================================ */

/* Screen-reader only — visually hidden but accessible */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ============================================================
   Button Base
   ============================================================ */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
  padding: 0.625rem var(--space-lg);
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  font-weight: 600;
  line-height: 1;
  text-align: center;
  text-decoration: none;
  white-space: nowrap;
  cursor: pointer;
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  transition:
    background-color var(--transition-base),
    border-color var(--transition-base),
    color var(--transition-base),
    box-shadow var(--transition-base);
  user-select: none;
  -webkit-user-select: none;
}

.btn:focus-visible {
  outline: 3px solid var(--color-blue);
  outline-offset: 2px;
}

.btn:disabled,
.btn[aria-disabled="true"] {
  opacity: 0.55;
  cursor: not-allowed;
  pointer-events: none;
}

/* Primary button */
.btn--primary {
  background-color: var(--color-blue);
  border-color: var(--color-blue);
  color: var(--color-white);
}

.btn--primary:hover {
  background-color: var(--color-blue-dark);
  border-color: var(--color-blue-dark);
  color: var(--color-white);
  text-decoration: none;
}

.btn--primary:active {
  background-color: var(--color-blue-dark);
}

/* Secondary button */
.btn--secondary {
  background-color: var(--color-black);
  border-color: var(--color-black);
  color: var(--color-white);
}

.btn--secondary:hover {
  background-color: #333333;
  border-color: #333333;
  color: var(--color-white);
  text-decoration: none;
}

/* Outline button */
.btn--outline {
  background-color: transparent;
  border-color: var(--color-blue);
  color: var(--color-blue);
}

.btn--outline:hover {
  background-color: var(--color-blue);
  color: var(--color-white);
  text-decoration: none;
}

/* Danger button */
.btn--danger {
  background-color: var(--color-danger);
  border-color: var(--color-danger);
  color: var(--color-white);
}

.btn--danger:hover {
  background-color: var(--color-danger-dark);
  border-color: var(--color-danger-dark);
  color: var(--color-white);
  text-decoration: none;
}

/* Small button modifier */
.btn--sm {
  padding: 0.375rem var(--space-md);
  font-size: var(--font-size-sm);
  border-radius: var(--radius-sm);
}

/* Full-width button modifier */
.btn--full {
  width: 100%;
}