/* ===================================
   CSS Custom Properties & Theme Support
   =================================== */

:root {
  /* Typography */
  --font-family-primary: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  --font-family-mono: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, 'Courier New', monospace;
  --font-size-base: 18px;
  --font-weight-normal: 400;
  --font-weight-bold: 600;
  --line-height-base: 1.6;

  /* Colors - Dark Theme (default) */
  --color-text-primary: #ffffff;
  --color-text-secondary: #b3b3b3;
  --color-text-muted: #808080;
  --color-background-primary: #1a1a1a;
  --color-background-secondary: #2d2d2d;
  --color-border: #404040;
  --color-link: #4dabf7;
  --color-link-hover: #339af0;

  /* Spacing */
  --space-1: 0.5rem;
  --space-2: 1rem;
  --space-3: 1.5rem;
  --space-4: 2rem;
  --space-6: 3rem;
  --space-8: 4rem;

  /* Borders */
  --border-width: 1.5px;
  --border-radius: 0.75rem;
  --border-style: solid;

  /* Form elements */
  --input-background: var(--color-background-primary);
  --input-border: var(--color-border);
  --input-text-color: var(--color-text-primary);
  --input-padding: 0.75rem;
  --input-focus-border: var(--color-link);
  --textarea-min-height: 6rem;

  /* Buttons */
  --button-background: #505050;
  --button-text-color: white;
  --button-padding: 0.75rem 1.5rem;
  --button-border-radius: var(--border-radius);
  --button-hover-background: #606060;

  /* Layout */
  --container-max-width: 75rem;
  --header-height: 4rem;
}

/* Light theme */
[data-theme="light"] {
  --color-text-primary: #1a1a1a;
  --color-text-secondary: #666;
  --color-text-muted: #999;
  --color-background-primary: #ffffff;
  --color-background-secondary: #f8f9fa;
  --color-border: #e1e5e9;
  --color-link: #0066cc;
  --color-link-hover: #004499;
}

/* ===================================
   Reset & Base Styles
   =================================== */

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-base);
  color: var(--color-text-primary);
  background-color: var(--color-background-primary);
  transition: background-color 0.3s ease, color 0.3s ease;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ===================================
   Typography
   =================================== */

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: var(--font-weight-bold);
  line-height: 1.2;
  margin-bottom: var(--space-1);
  color: var(--color-text-primary);
}

h1 {
  font-size: 2rem;
}

h2 {
  font-size: 1.75rem;
}

h3 {
  font-size: 1.5rem;
}

h4 {
  font-size: 1.25rem;
}

p {
  margin-bottom: var(--space-1);
  color: var(--color-text-secondary);
}

a {
  color: var(--color-link);
  text-decoration: none;
  transition: color 0.2s ease;

  &:hover {
    color: var(--color-link-hover);
  }
}

/* ===================================
   Theme Toggle
   =================================== */

#theme-toggle {
  background: none;
  border: var(--border-width) var(--border-style) var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-1);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
  color: var(--color-text-primary);
  margin-left: auto;

  &:hover {
    background-color: var(--color-background-secondary);
    border-color: var(--color-link);
  }

  &:focus {
    outline: 2px solid var(--color-link);
    outline-offset: 2px;
  }

  &:active {
    animation: spin 0.3s ease-in-out;
  }
}

@keyframes spin {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* ===================================
   Layout Elements
   =================================== */

header {
  background-color: var(--color-background-primary);
  border-bottom: var(--border-width) var(--border-style) var(--color-border);
  position: sticky;
  top: 0;
  z-index: 1000;
  transition: background-color 0.3s ease, border-color 0.3s ease;
}

nav {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: var(--space-1);
  display: flex;
  justify-content: space-between;
  align-items: center;

  img {
    height: 2.5rem;
    width: auto;
    transition: opacity 0.2s ease;

    &:hover {
      opacity: 0.8;
    }
  }

  ul {
    list-style: none;
    display: flex;
    gap: var(--space-2);
  }

  a {
    padding: var(--space-1) var(--space-3);
    color: var(--color-text-primary);
    font-weight: var(--font-weight-normal);
    background-color: var(--color-background-secondary);
    border-radius: var(--border-radius);
    border: var(--border-width) var(--border-style) var(--color-border);
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.2),
                0 1px 2px rgba(0, 0, 0, 0.1);
    transition: all 0.2s ease;
    display: inline-block;

    &:hover {
      background-color: #505050;
      color: white;
      transform: translateY(-1px);
      box-shadow: 0 4px 8px rgba(0, 0, 0, 0.3),
                  0 2px 4px rgba(0, 0, 0, 0.2);
      border-color: #606060;
    }

    &:active {
      transform: translateY(0);
      box-shadow: 0 1px 2px rgba(0, 0, 0, 0.2);
    }
  }
}

main {
  max-width: var(--container-max-width);
  margin: 0 auto;
  padding: var(--space-1);
  flex: 1;
}

section {
  background-color: var(--color-background-primary);
  padding: var(--space-1);
  margin-bottom: var(--space-4);
  border-radius: var(--border-radius);
  border: var(--border-width) var(--border-style) var(--color-border);
  transition: background-color 0.3s ease, border-color 0.3s ease;

  h2 {
    color: var(--color-text-primary);
    border-bottom: 3px solid var(--color-link);
    padding-bottom: var(--space-1);
    margin-bottom: var(--space-3);
  }

  ul {
    display: grid;
    gap: var(--space-2);
    grid-template-columns: 1fr;
  }

  li {
    padding: var(--space-2);
    background-color: var(--color-background-secondary);
    border-radius: var(--border-radius);
    border-left: 4px solid var(--color-link);
  }

  h3 {
    margin-bottom: var(--space-1);
  }
}

article {
  margin-top: 1rem;
  margin-bottom: var(--space-3);
  padding-bottom: var(--space-3);
  border-bottom: var(--border-width) var(--border-style) var(--color-border);

  &:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
  }
}

footer {
  background-color: var(--color-background-secondary);
  color: var(--color-text-primary);
  padding: var(--space-3) var(--space-2);
  border-top: var(--border-width) var(--border-style) var(--color-border);
  display: flex;
  flex-direction: row;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-2);

  small {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.5rem 1rem;
    background: linear-gradient(135deg, #3a3a3a 0%, #2d2d2d 100%);
    border: 1px solid #505050;
    border-radius: 2rem;
    box-shadow: 0 2px 8px rgba(0, 0, 0, 0.3),
                inset 0 1px 0 rgba(255, 255, 255, 0.1);
    font-size: 0.875rem;
    font-weight: 500;
    color: #b3b3b3;
    transition: all 0.3s ease;

    svg {
      flex-shrink: 0;
      opacity: 0.8;
    }

    a {
      color: #e0e0e0;
      font-weight: 600;
      text-decoration: none;
      transition: all 0.2s ease;

      &:hover {
        color: white;
        text-shadow: 0 0 8px rgba(255, 255, 255, 0.3);
      }
    }

    &:hover {
      transform: translateY(-2px);
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.4),
                  inset 0 1px 0 rgba(255, 255, 255, 0.15);
      border-color: #606060;
    }
  }

  p {
    font-size: 0.75rem;
    color: #666;
    margin: 0;
    text-align: center;

    a {
      color: #666;
      text-decoration: none;
      transition: color 0.2s ease;

      &:hover {
        color: #999;
      }
    }
  }
}

[data-theme="light"] footer small {
  background: linear-gradient(135deg, #f0f0f0 0%, #e5e5e5 100%);
  border-color: #d0d0d0;
  color: #666;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1),
              inset 0 1px 0 rgba(255, 255, 255, 0.8);

  a {
    color: #333;

    &:hover {
      color: #000;
      text-shadow: 0 0 8px rgba(0, 0, 0, 0.1);
    }
  }

  &:hover {
    box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15),
                inset 0 1px 0 rgba(255, 255, 255, 0.9);
    border-color: #b0b0b0;
  }
}

[data-theme="light"] footer p a {
  color: #999;

  &:hover {
    color: #666;
  }
}

/* ===================================
   Lists
   =================================== */

ul {
  list-style: none;
}


/* ===================================
   Forms
   =================================== */

form {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  max-width: 40rem;

  label {
    font-weight: var(--font-weight-normal);
    color: var(--color-text-primary);
    margin-bottom: 0.25rem;
  }

  input,
  textarea {
    width: 100%;
    padding: var(--input-padding);
    border: var(--border-width) var(--border-style) var(--input-border);
    border-radius: var(--border-radius);
    font-size: var(--font-size-base);
    font-family: var(--font-family-primary);
    background-color: var(--input-background);
    color: var(--input-text-color);
    transition: border-color 0.2s ease;

    &:focus {
      outline: none;
      border-color: var(--input-focus-border);
    }
  }

  textarea {
    resize: vertical;
    min-height: var(--textarea-min-height);
  }

  button {
    align-self: flex-start;
  }
}

/* ===================================
   Buttons
   =================================== */

button {
  padding: var(--button-padding);
  background-color: var(--button-background);
  color: var(--button-text-color);
  border: none;
  border-radius: var(--button-border-radius);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  cursor: pointer;
  transition: background-color 0.2s ease;

  &:hover {
    background-color: var(--button-hover-background);
  }

  &:active {
    transform: translateY(1px);
  }
}

/* ===================================
   Dialog
   =================================== */

dialog {
  position: fixed;
  inset: 0;
  margin: auto;
  width: 30rem;
  max-width: 90vw;
  height: fit-content;
  border: 2px solid var(--color-border);
  border-radius: var(--border-radius);
  padding: var(--space-4);
  background-color: var(--color-background-primary);
  color: var(--color-text-primary);

  p {
    white-space: normal;
    word-wrap: break-word;
    overflow-wrap: break-word;
    max-width: 100%;
  }

  div {
    display: flex;
    gap: var(--space-1);
    margin-top: var(--space-2);
  }
}

dialog::backdrop {
  background: rgba(0, 0, 0, 0.5);
}



/* ===================================
   Responsive Design
   =================================== */

@media (min-width: 48rem) {
  h1 {
    font-size: 2.5rem;
  }

  h2 {
    font-size: 2rem;
  }

  h3 {
    font-size: 1.75rem;
  }
  
  nav {
    padding: var(--space-3) var(--space-4);
  }

  main {
    padding: var(--space-4);
  }

  section {
    padding: var(--space-6) var(--space-4);
  }
  
}

@media (min-width: 64rem) {
  section {
    ul {
      grid-template-columns: repeat(2, 1fr);
    }
  }
  
  /* section {
    padding: var(--space-8) var(--space-6);
  } */
}