/* --- Global Styles & Variables --- */
:root {
    --dark-bg: #1a1a2e; /* Deep purple/blue */
    --primary-text: #e0e0e0; /* Light grey */
    --highlight-primary: #8a4fff; /* Electric purple */
    --highlight-secondary: #00f5d4; /* Bright cyan */
    --card-bg: #2a2a3e;
    --border-color: #4a4a5e;
    --link-color: var(--highlight-secondary);
    --link-hover: #ffffff;
    --button-bg: var(--highlight-primary);
    --button-text: #ffffff;
    --button-hover-bg: #7a3fef;

    --font-family: 'Inter', sans-serif;
    --container-width: 1100px;
    --container-padding: 1rem;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-family);
    background-color: var(--dark-bg);
    color: var(--primary-text);
    line-height: 1.6;
    font-size: 16px;
}

.container {
    max-width: var(--container-width);
    margin-left: auto;
    margin-right: auto;
    padding-left: var(--container-padding);
    padding-right: var(--container-padding);
}

h1, h2, h3, h4 {
    line-height: 1.2;
    margin-bottom: 1rem;
    font-weight: 700;
}

h1 {
    font-size: 2.5rem; /* Responsive adjustments below */
    font-weight: 800;
}

h2 {
    font-size: 2rem;
    margin-top: 2.5rem;
    border-bottom: 2px solid var(--highlight-primary);
    padding-bottom: 0.5rem;
    display: inline-block;
}

h3 {
    font-size: 1.5rem;
    color: var(--highlight-secondary);
}

h4 {
    font-size: 1.2rem;
    color: var(--highlight-primary);
}

p {
    margin-bottom: 1rem;
}

a {
    color: var(--link-color);
    text-decoration: none;
    transition: color 0.3s ease;
}

a:hover, a:focus {
    color: var(--link-hover);
    text-decoration: underline;
}

ul {
    list-style: disc;
    margin-left: 2rem;
    margin-bottom: 1rem;
}

li {
    margin-bottom: 0.5rem;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.highlight {
    color: var(--highlight-primary);
}

.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;
}

/* --- Header & Navigation --- */
header {
    background-color: rgba(26, 26, 46, 0.8); /* Slightly transparent */
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 1000;
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: #ffffff;
    text-decoration: none;
}

.logo:hover, .logo:focus {
    color: var(--highlight-secondary);
}

.nav-links {
    list-style: none;
    display: flex;
    gap: 1.5rem;
    margin: 0;
}

.nav-links a {
    color: var(--primary-text);
    font-weight: 700;
    padding: 0.5rem 0;
    position: relative;
}

.nav-links a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: 0;
    left: 0;
    background-color: var(--highlight-secondary);
    transition: width 0.3s ease;
}

.nav-links a:hover::after, .nav-links a:focus::after {
    width: 100%;
}

.mobile-nav-toggle {
    display: none; /* Hidden by default, shown in media query */
    background: transparent;
    border: 0;
    cursor: pointer;
    padding: 0.5rem;
}

.mobile-nav-toggle .icon-hamburger,
.mobile-nav-toggle .icon-close {
    display: block;
    width: 24px;
    height: 2px;
    background-color: #ffffff;
    position: relative;
    transition: transform 0.3s ease-out;
}

.mobile-nav-toggle .icon-hamburger::before,
.mobile-nav-toggle .icon-hamburger::after {
    content: '';
    position: absolute;
    left: 0;
    width: 24px;
    height: 2px;
    background-color: #ffffff;
    transition: transform 0.3s ease-out, opacity 0.3s ease-out;
}

.mobile-nav-toggle .icon-hamburger::before {
    top: -7px;
}

.mobile-nav-toggle .icon-hamburger::after {
    top: 7px;
}

.mobile-nav-toggle[aria-expanded="true"] .icon-hamburger {
    background-color: transparent; /* Hide middle line */
}

.mobile-nav-toggle[aria-expanded="true"] .icon-hamburger::before {
    transform: translateY(7px) rotate(45deg);
}

.mobile-nav-toggle[aria-expanded="true"] .icon-hamburger::after {
    transform: translateY(-7px) rotate(-45deg);
}

/* --- Hero Section --- */
.hero {
    padding: 4rem 0;
    text-align: center;
    background: linear-gradient(rgba(26, 26, 46, 0.85), rgba(26, 26, 46, 0.95)), url('https://via.placeholder.com/1500x800/1a1a2e/8a4fff?text=Abstract+Background') no-repeat center center/cover; /* Placeholder background */
}

.hero h1 {
    margin-bottom: 1rem;
    color: #ffffff;
}

.hero .intro {
    font-size: 1.1rem;
    max-width: 700px;
    margin: 0 auto 2rem auto;
    color: #c0c0c0;
}

.cta-button {
    display: inline-block;
    background-color: var(--button-bg);
    color: var(--button-text);
    padding: 0.8rem 2rem;
    border-radius: 5px;
    font-weight: 700;
    text-decoration: none;
    transition: background-color 0.3s ease, transform 0.2s ease;
}

.cta-button:hover, .cta-button:focus {
    background-color: var(--button-hover-bg);
    color: var(--button-text);
    transform: translateY(-2px);
    text-decoration: none;
}

/* --- Highlights Section --- */
.highlights-section {
    padding: 3rem 0;
}

.section-title {
    text-align: center;
    margin-bottom: 2.5rem;
}

.highlights-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 1.5rem;
}

.highlight-card {
    background-color: var(--card-bg);
    padding: 1.5rem;
    border-radius: 8px;
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.highlight-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0, 245, 212, 0.1);
}

.highlight-card h3 {
    margin-bottom: 0.8rem;
}

.learn-more {
    display: inline-block;
    margin-top: 1rem;
    font-weight: 700;
    color: var(--highlight-secondary);
}

/* --- Snippets Section --- */
.snippets-section {
    padding: 3rem 0;
    background-color: var(--card-bg); /* Slightly different background */
}

.snippets-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 2rem;
}

.snippet-card {
    padding: 1.5rem;
    border-left: 4px solid var(--highlight-primary);
}

.snippet-card h4 {
    margin-bottom: 0.5rem;
}

.inline-link {
    font-weight: 700;
}

/* --- Page Content --- */
.page-content {
    padding: 3rem 0;
}

.page-title {
    margin-bottom: 2rem;
    text-align: center;
}

.content-section {
    margin-bottom: 2.5rem;
    max-width: 800px; /* Limit width for readability */
    margin-left: auto;
    margin-right: auto;
}

.content-section h2 {
    margin-top: 0; /* Reset top margin for section titles */
    margin-bottom: 1.5rem;
}

.disclaimer {
    margin-top: 3rem;
    font-size: 0.9rem;
    font-style: italic;
    color: #a0a0a0;
    border-top: 1px solid var(--border-color);
    padding-top: 1rem;
}

/* --- Footer --- */
footer {
    background-color: var(--card-bg);
    color: #a0a0a0;
    padding: 2rem 0;
    margin-top: 3rem;
    text-align: center;
    font-size: 0.9rem;
    border-top: 1px solid var(--border-color);
}

footer .container {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
}

footer nav a {
    color: #a0a0a0;
    margin: 0 0.5rem;
}

footer nav a:hover, footer nav a:focus {
    color: #ffffff;
}

footer p {
    margin-bottom: 0;
}

/* --- Responsive Design --- */
@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }

    h2 {
        font-size: 1.75rem;
    }

    .nav-links {
        position: fixed;
        inset: 0 0 0 30%; /* Slide in from right */
        flex-direction: column;
        padding: min(20vh, 10rem) 2rem;
        gap: 2rem;
        background-color: rgba(26, 26, 46, 0.95); /* Darker, less transparent */
        backdrop-filter: blur(15px);
        transform: translateX(100%);
        transition: transform 350ms ease-out;
    }

    .nav-links[data-visible="true"] {
        transform: translateX(0%);
    }

    .mobile-nav-toggle {
        display: block;
        position: absolute;
        z-index: 9999;
        top: 1.5rem;
        right: 1rem;
    }

    .hero {
        padding: 3rem 0;
    }

    .highlights-grid,
    .snippets-grid {
        grid-template-columns: 1fr; /* Stack cards on smaller screens */
    }
}