:root {
    --bg-color: #f5f5f5;
    --container-bg: #ffffff;
    --text-color: #333333;
    --border-color: #dddddd;
    --link-color: #0066cc;
    --link-hover: #004499;
    --disabled-color: #999999;
    --pre-bg: #f5f5f5;
    --pre-border: #dddddd;
    --shadow: rgba(0,0,0,0.1);
}

[data-theme="dark"] {
    --bg-color: #1a1a1a;
    --container-bg: #2d2d2d;
    --text-color: #e4e4e4;
    --border-color: #444444;
    --link-color: #6699ff;
    --link-hover: #99bbff;
    --disabled-color: #666666;
    --pre-bg: #252525;
    --pre-border: #404040;
    --shadow: rgba(0,0,0,0.3);
    --accent-border: #f15a24;
}

/* Auto dark mode based on system preference */
@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) {
        --bg-color: #1a1a1a;
        --container-bg: #2d2d2d;
        --text-color: #e4e4e4;
        --border-color: #444444;
        --link-color: #6699ff;
        --link-hover: #99bbff;
        --disabled-color: #666666;
        --pre-bg: #252525;
        --pre-border: #404040;
        --shadow: rgba(0,0,0,0.3);
        --accent-border: #f15a24;
    }
}

* {
    box-sizing: border-box;
}

body {
    font-family: tahoma, verdana;
    line-height: 1.6;
    margin: 0 auto;
    padding: 20px;
    background-color: var(--bg-color);
    color: var(--text-color);
    transition: background-color 0.3s ease, color 0.3s ease;
}

.container {
    max-width: 800px;
    margin: 0 auto;
    background-color: var(--container-bg);
    padding: 40px;
    box-shadow: 0 0 10px var(--shadow);
    transition: background-color 0.3s ease, box-shadow 0.3s ease, border 0.3s ease;
}

/* Add accent border in dark mode only */
[data-theme="dark"] .container {
    border: 1px solid var(--accent-border);
}

@media (prefers-color-scheme: dark) {
    :root:not([data-theme="light"]) .container {
        border: 1px solid var(--accent-border);
    }
}

/* Mobile adjustments */
@media (max-width: 600px) {
    body {
        padding: 10px;
    }
    .container {
        padding: 20px;
    }
}

.theme-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    background: var(--container-bg);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 50px;
    height: 50px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    box-shadow: 0 2px 5px var(--shadow);
    transition: all 0.3s ease;
    z-index: 1000;
}

.theme-toggle:hover {
    transform: scale(1.1);
}

@media (max-width: 600px) {
    .theme-toggle {
        width: 40px;
        height: 40px;
        font-size: 20px;
        top: 10px;
        right: 10px;
    }
}

h1 {
    border-bottom: 2px solid var(--text-color);
    padding-bottom: 10px;
    transition: border-color 0.3s ease;
}

.navigation {
    display: flex;
    justify-content: space-between;
    margin: 20px 0;
    padding: 15px 0;
    border-top: 1px solid var(--border-color);
    border-bottom: 1px solid var(--border-color);
    transition: border-color 0.3s ease;
}

.nav-link {
    text-decoration: none;
    color: var(--link-color);
    padding: 5px 10px;
    transition: color 0.3s ease;
}

.nav-link:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

.nav-link.disabled {
    color: var(--disabled-color);
    pointer-events: none;
}

p {
    margin: 1em 0;
    text-align: justify;
}

@media (max-width: 600px) {
    p {
        text-align: left;
    }
}

hr.separator {
    border: none;
    border-top: 1px solid var(--border-color);
    margin: 2em auto;
    width: 50%;
    transition: border-color 0.3s ease;
}

pre {
    background-color: var(--pre-bg);
    border: 1px solid var(--pre-border);
    border-radius: 4px;
    padding: 15px;
    overflow-x: auto;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
    line-height: 1.4;
    transition: background-color 0.3s ease, border-color 0.3s ease;
}

@media (max-width: 600px) {
    pre {
        font-size: 0.8em;
        padding: 10px;
    }
}

footer {
    margin-top: 3em;
    padding-top: 2em;
    border-top: 1px solid var(--border-color);
    text-align: center;
    font-size: 0.9em;
    color: var(--disabled-color);
}

/* Index page specific styles */
.book-header {
    text-align: center;
    margin-bottom: 3em;
}

.book-title {
    font-size: 3em;
    margin-bottom: 0.2em;
    border-bottom: none;

    font-family: "Russo One", sans-serif;
    font-weight: 400;
    font-style: normal;

}

.book-author {
    font-size: 1.3em;
    color: var(--disabled-color);
    margin-bottom: 0.5em;
}

.book-year {
    font-size: 1em;
    color: var(--disabled-color);
}

.start-button {
    display: inline-block;
    margin: 2em 0;
    padding: 15px 40px;
    background-color: var(--link-color);
    color: white;
    text-decoration: none;
    border-radius: 5px;
    font-size: 1.2em;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.start-button:hover {
  background-color: var(--link-hover);
  transform: none;
  box-shadow: 0 0 0 3px rgba(102, 153, 255, 0.25);
}


.start-button:hover {
    background-color: var(--link-hover);
    transform: translateY(-2px);
}

.chapter-list {
    margin-top: 3em;
    padding-top: 2em;
    border-top: 1px solid var(--border-color);
}

.chapter-list h2 {
    font-size: 1.2em;
    color: var(--disabled-color);
    margin-bottom: 1em;
}

.chapter-list ul {
    list-style: none;
    padding: 0;
}

.chapter-list li {
    margin: 0.5em 0;
}

.chapter-list a {
    color: var(--link-color);
    text-decoration: none;
}

.chapter-list a:hover {
    color: var(--link-hover);
    text-decoration: underline;
}

.book-blurb {
  margin: 1.5em auto 0;
  max-width: 640px;
  text-align: center;
  text-wrap: pretty;
}

.full-width-img {
  width: 100%;
  height: auto;
  margin: 1em 0;
}

.theme-buttons {
  display: flex;
  gap: 10px;
  justify-content: center;
  margin: 1.5em 0;
}

.theme-btn {
  padding: 8px 20px;
  border: 1px solid;
  border-radius: 4px;
  font-size: 0.9em;
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: inherit;
}

.light-btn {
  background-color: #f5f5f5;
  color: #333333;
  border-color: #dddddd;
}

.light-btn:hover {
  background-color: #e8e8e8;
  transform: translateY(-1px);
}

.dark-btn {
  background-color: #2d2d2d;
  color: #e4e4e4;
  border-color: #444444;
}

.dark-btn:hover {
  background-color: #3a3a3a;
  transform: translateY(-1px);
}