:root {
    --bg-color: #0f172a;
    /* Deep Navy/Slate background */
    --text-color: #e2e8f0;
    /* Soft white/slate for high readability */
    --accent-color: #94a3b8;
    /* Muted slate/blue for secondary elements */
    --heading-color: #f8fafc;
    /* Brightest white for headers */
    --border-color: #1e293b;
    /* Dark subtle borders */
    --code-bg: #1e293b;
    --code-text: #60a5fa;
    /* Blue accent for code */
    --font-main: 'Inter', system-ui, -apple-system, sans-serif;
    --font-heading: 'Outfit', sans-serif;
    --line-height: 1.5;
    --container-width: 42rem;
}

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

body {
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: var(--font-main);
    line-height: var(--line-height);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

.container {
    padding: 0 1.5rem;
    margin: 0 auto;
    max-width: var(--container-width);
}

.top-nav {
    position: absolute;
    top: 1rem;
    right: 0;
    width: 100%;
    z-index: 10;
}

.top-nav .container {
    display: flex;
    justify-content: flex-end;
}

.home-link {
    color: var(--accent-color) !important;
    text-decoration: none !important;
    font-size: 0.9rem;
    font-weight: 500;
    padding: 0.5rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 0.5rem;
    transition: all 0.2s ease;
}

.home-link:hover {
    color: var(--heading-color) !important;
    background-color: var(--border-color);
    border-color: var(--accent-color);
}

header {
    background-color: #0f172a;
    border-bottom: 1px solid var(--border-color);
    padding: 4rem 0 3rem;
    margin-bottom: 2rem;
}

h1 {
    font-family: var(--font-heading);
    font-size: 2.5rem;
    color: var(--heading-color);
    line-height: 1.2;
    margin-bottom: 0.5rem;
}

.subtitle {
    font-size: 1.25rem;
    color: var(--accent-color);
    font-weight: 500;
}

main {
    padding-bottom: 8rem;
}

article {
    margin-bottom: 2.5rem;
}

h2 {
    font-family: var(--font-heading);
    font-size: 1.75rem;
    color: var(--heading-color);
    margin: 2rem 0 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border-color);
    display: inline-block;
}

h3 {
    font-size: 1.25rem;
    color: var(--heading-color);
    margin: 1.25rem 0 0.5rem;
}

h4 {
    font-size: 1.1rem;
    color: var(--accent-color);
    margin: 1rem 0 0.35rem;
}

h5 {
    font-size: 1rem;
    color: var(--accent-color);
    margin: 0.75rem 0 0.25rem;
    font-style: italic;
}

p {
    margin-bottom: 1rem;
}

ul,
ol {
    margin-bottom: 1rem;
    padding-left: 1.5rem;
}

li {
    margin-bottom: 0.5rem;
}

/* Table of Contents Styling */
.toc {
    background: rgba(30, 41, 59, 0.5);
    backdrop-filter: blur(8px);
    border: 1px solid var(--border-color);
    border-radius: 1rem;
    padding: 1.25rem 1.5rem;
    margin: 2rem 0 4rem;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
}

.toc h2 {
    font-size: 1.25rem;
    margin: 0 0 1rem;
    padding-bottom: 0.5rem;
    display: block;
    border-bottom: 1px solid var(--border-color);
}

.toc ul {
    list-style: none;
    padding-left: 0;
    margin-bottom: 0;
}

.toc li {
    margin-bottom: 0.35rem;
}

.toc li:last-child {
    margin-bottom: 0;
}

.toc a {
    text-decoration: none;
    font-weight: 500;
    color: var(--accent-color);
    font-size: 0.95rem;
    display: block;
    transition: all 0.2s ease;
}

.toc a:hover {
    color: var(--heading-color);
    transform: translateX(4px);
}

.toc ul ul {
    margin-top: 0.35rem;
    padding-left: 1rem;
    border-left: 1px solid var(--border-color);
}

.toc ul ul li {
    font-size: 0.9rem;
    margin-bottom: 0.25rem;
}

.toc ul ul a {
    font-weight: 400;
}

li ul,
li ol {
    margin-top: 0.5rem;
    margin-bottom: 0.5rem;
}

code {
    font-family: SFMono-Regular, Consolas, 'Liberation Mono', Menlo, monospace;
    background-color: var(--code-bg);
    color: var(--code-text);
    padding: 0.2rem 0.4rem;
    border-radius: 0.25rem;
    font-size: 0.9em;
}

section {
    margin-bottom: 1.5rem;
}

hr {
    border: 0;
    height: 1px;
    background: var(--border-color);
    margin: 4rem 0;
}

a {
    color: #60a5fa;
    /* Vibrant but readable blue */
    text-decoration: underline;
    text-underline-offset: 4px;
    transition: color 0.2s ease;
}

a:hover {
    color: #93c5fd;
}

footer {
    margin-top: 4rem;
    padding-top: 2rem;
    border-top: 1px solid var(--border-color);
    font-size: 0.95rem;
    color: var(--accent-color);
}

#sources h2 {
    font-size: 1.5rem;
}

#sources p {
    margin-bottom: 1rem;
    line-height: 1.4;
}

@media (max-width: 640px) {
    header {
        padding: 3rem 0 2rem;
    }

    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.5rem;
    }
}