/* Prevent horizontal overflow on mobile */
* {
    box-sizing: border-box;
}

html, body {
    max-width: 100%;
    overflow-x: hidden;
}

/* Content page variables - Light theme (default) */
:root {
    --content-primary: #2c4c7c;
    --content-secondary: #1e40af;
    --content-tertiary: #3b82f6;
    
    --content-bg: #f8fafc;
    --content-surface: #ffffff;
    --content-border: #e2e8f0;
    
    --content-text: #1e293b;
    --content-text-secondary: #64748b;
    --content-text-light: #94a3b8;
    --content-text-inverse: #ffffff;
    
    --content-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --content-shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);
    
    --content-hover: rgba(59, 130, 246, 0.08);

    /* Panel/Ad backgrounds (light) */
    --panel-bg: #ffffff;
    --panel-bg-2: #eef2f7;
    --panel-border: #d8e0ea;
    --ad-bg: #f1f5f9;      /* subtle light */
    --ad-bg-2: #e5edf6;    /* tint to match theme */
    --ad-label: #64748b;

    /* Aliases and supplemental tokens used below (light mode) */
    --dark-color: #1e293b;                /* used by footer gradient */
    --primary-color: var(--content-primary);
    --secondary-color: var(--content-secondary);
    --accent-color: var(--content-tertiary);
    --surface-color: var(--content-surface);
    --border-color: var(--content-border);
    --text-primary: var(--content-text);
    --light-color: #ffffff;
    --success-color: #22c55e;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.06);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

/* Dark theme content overrides */
[data-theme="dark"], .theme-dark {
    --content-primary: #3b82f6;
    --content-secondary: #1d4ed8;
    --content-tertiary: #60a5fa;
    
    --content-bg: #0f172a;
    --content-surface: #1e293b;
    --content-border: #374151;
    
    --content-text: #f1f5f9;
    --content-text-secondary: #cbd5e1;
    --content-text-light: #94a3b8;
    --content-text-inverse: #0f172a;
    
    --content-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.3);
    --content-shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.4);
    
    --content-hover: rgba(96, 165, 250, 0.12);

    /* Panel/Ad backgrounds (dark) */
    --panel-bg: #162131;   /* darker than surface */
    --panel-bg-2: #0f172a; /* blend to site bg */
    --panel-border: #2a3a52;
    --ad-bg: #0f1a2a;      /* cool dark */
    --ad-bg-2: #1a2740;    /* slight gradient */
    --ad-label: #94a3b8;

    /* Aliases and supplemental tokens used below (dark mode) */
    --dark-color: #0b1220;               /* slightly darker than bg for gradient depth */
    --primary-color: var(--content-primary);
    --secondary-color: var(--content-secondary);
    --accent-color: #60a5fa;
    --surface-color: var(--content-surface);
    --border-color: var(--content-border);
    --text-primary: var(--content-text);
    --light-color: #ffffff;
    --success-color: #22c55e;
    --shadow-sm: 0 1px 2px rgba(0, 0, 0, 0.4);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.5);
}

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

@import 'https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700&display=swap';

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.6;
    color: var(--content-text);
    background: var(--content-bg);
    font-weight: 400;
    min-height: 100vh;
    transition: all 0.3s ease;
}

/* Header */
.header {
    background: linear-gradient(135deg, var(--content-primary) 0%, var(--content-secondary) 100%);
    color: var(--content-text-inverse);
    padding: 4rem 0 3rem;
    text-align: center;
    position: relative;
    box-shadow: var(--content-shadow);
}

.header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 'data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="grain" width="100" height="100" patternUnits="userSpaceOnUse"><circle cx="25" cy="25" r="1" fill="white" opacity="0.1"/><circle cx="75" cy="75" r="1" fill="white" opacity="0.1"/><circle cx="50" cy="10" r="0.5" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23grain"/></svg>';
    pointer-events: none;
}

.header h1 {
    font-size: 3rem;
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -0.025em;
    position: relative;
    z-index: 1;
    color: white !important;
}

.header .tagline {
    font-size: 1.25rem;
    opacity: 0.9;
    margin-bottom: 1rem;
    font-weight: 400;
    position: relative;
    z-index: 1;
}

.header .author {
    font-size: 1rem;
    color: rgba(255, 255, 255, 0.8);
    font-weight: 500;
    position: relative;
    z-index: 1;
}

/* Navigation */
.nav {
    background: var(--content-surface);
    border-bottom: 1px solid var(--content-border);
    padding: 0;
    box-shadow: var(--content-shadow);
    top: 0;
    z-index: 100;
}

.nav-container {
    max-width: 1400px;
    margin: 0 auto;
    display: flex;
    justify-content: center;
    gap: 0;
    position: relative;
}

/* Add theme toggle to navigation */
.nav-container::after {
    content: '';
    position: absolute;
    right: 2rem;
    top: 50%;
    transform: translateY(-50%);
}

.nav a {
    color: var(--content-text-secondary);
    text-decoration: none;
    padding: 1.25rem 2.5rem;
    font-weight: 500;
    transition: all 0.3s ease;
    border-bottom: 3px solid transparent;
    position: relative;
}

.nav a:hover {
    color: var(--content-primary);
    background: var(--content-hover);
    transform: translateY(-1px);
}

.nav a.active {
    color: var(--content-primary);
    border-bottom-color: var(--content-primary);
    background: var(--content-hover);
    font-weight: 600;
}

/* Theme toggle button */
.c-btn {
    padding: 0.75rem 1.5rem 0.75rem 2.5rem;
    border: 2px solid var(--content-border);
    border-radius: 8px;
    background-color: var(--content-surface);
    color: var(--content-text);
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    position: relative;
    overflow: hidden;
    min-width: 120px;
    white-space: nowrap;
}

.c-btn:hover {
    background-color: var(--content-hover);
    transform: translateY(-1px);
}

.c-btn--tertiary {
    background-color: var(--content-tertiary);
    color: var(--content-text-inverse);
    border-color: var(--content-tertiary);
}

/* Theme toggle icons for content page */
#servoTestBtn::before {
    content: '\2600';  /* ☀ sun text glyph */
    position: absolute;
    top: 50%;
    left: 12px;
    transform: translateY(-50%);
    font-size: 1rem;
    opacity: 1;
    transition: all 0.3s ease;
    pointer-events: none;
    width: 1.2rem;
    height: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
}

[data-theme="dark"] #servoTestBtn::before,
.theme-dark #servoTestBtn::before {
    content: '\263E';  /* ☾ moon text glyph */
    opacity: 1;
}

/* Main Container */
.container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 3rem 2rem;
}

/* Section Content */
.section-content {
    display: none;
}

.section-content.active {
    display: block;
}

/* Article Selector */
.article-selector {
    margin: 2.5rem 0;
    max-width: 100%;
    overflow: hidden;
}

.article-selector select {
    width: 100%;
    padding: 1.25rem 1.5rem;
    font-size: 1.125rem;
    border: 2px solid var(--content-border);
    border-radius: 12px;
    background: var(--content-surface);
    color: var(--content-text);
    font-family: inherit;
    transition: all 0.3s ease;
    appearance: none;
    background-image: "data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 20 20'%3e%3cpath stroke='%236b7280' stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='m6 8 4 4 4-4'/%3e%3c/svg%3e";
    background-position: right 1rem center;
    background-repeat: no-repeat;
    background-size: 1.25rem;
    box-shadow: var(--content-shadow);
    font-weight: 500;
    max-width: 100%;
}

/* Mobile optimization for article selector */
@media (max-width: 768px) {
    .article-selector select {
        padding: 0.875rem 1rem;
        padding-right: 2.5rem;
        font-size: 1rem;
        background-position: right 0.75rem center;
        background-size: 1rem;
    }
    
    .article-selector select option {
        padding: 0.5rem;
    }
}

@media (max-width: 480px) {
    .article-selector select {
        padding: 0.75rem 0.875rem;
        padding-right: 2.25rem;
        font-size: 0.9rem;
        background-position: right 0.625rem center;
        background-size: 0.875rem;
    }
    
    .article-selector select option {
        /* Truncate very long option text on small screens */
        max-width: 100%;
        overflow: hidden;
        text-overflow: ellipsis;
        white-space: nowrap;
    }
}

.article-selector select:focus {
    outline: none;
    border-color: var(--content-primary);
    box-shadow: 0 0 0 4px rgba(59, 130, 246, 0.1), var(--content-shadow);
    transform: translateY(-1px);
}

/* Article Display */
.article {
    background: var(--content-surface);
    border-radius: 16px;
    box-shadow: var(--content-shadow);
    margin: 3rem 0;
    overflow: hidden;
    border: 1px solid var(--content-border);
    backdrop-filter: blur(10px);
    position: relative;
}

.article::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--content-primary) 0%, var(--content-tertiary) 100%);
}

.article-header {
    padding: 3.5rem 3rem;
    background: linear-gradient(135deg, var(--content-primary) 0%, var(--content-secondary) 100%);
    color: var(--content-text-inverse);
    position: relative;
}

.article-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 'data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="dots" width="20" height="20" patternUnits="userSpaceOnUse"><circle cx="10" cy="10" r="1" fill="white" opacity="0.1"/></pattern></defs><rect width="100" height="100" fill="url(%23dots"/></svg>';
    pointer-events: none;
}

.article-title {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 1.5rem;
    line-height: 1.2;
    letter-spacing: -0.025em;
    position: relative;
    z-index: 1;
}

.article-intro {
    font-size: 1.25rem;
    line-height: 1.6;
    opacity: 0.95;
    font-weight: 400;
    position: relative;
    z-index: 1;
}

.article-content {
    padding: 4rem 3rem;
    background: var(--content-surface);
    color: var(--content-text);
}

.highlights {
    margin-bottom: 3rem;
    display: grid;
    gap: 1.5rem;
}

.highlight {
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.03) 0%, rgba(37, 99, 235, 0.08) 100%);
    border-left: 5px solid var(--accent-color);
    padding: 2rem;
    border-radius: 0 12px 12px 0;
    transition: all 0.3s ease;
    position: relative;
    box-shadow: var(--shadow-sm);
}

.highlight:hover {
    transform: translateX(5px);
    box-shadow: var(--shadow-md);
}

.highlight h4 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-size: 1.25rem;
    font-weight: 600;
}

.highlight p {
    margin: 0;
    color: var(--text-primary);
    line-height: 1.7;
    font-size: 1.05rem;
}

.section {
    margin: 3rem 0;
    padding: 2rem 0;
}

.section h3 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    font-size: 1.5rem;
    font-weight: 600;
    padding-bottom: 0.75rem;
    border-bottom: 3px solid var(--border-color);
    position: relative;
}

.section h3::after {
    content: '';
    position: absolute;
    bottom: -3px;
    left: 0;
    width: 60px;
    height: 3px;
    background: var(--accent-color);
}

.section p {
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    line-height: 1.8;
    font-size: 1.05rem;
}

.section ul {
    list-style: none;
    padding: 0;
    margin: 2rem 0;
}

.section li {
    padding: 1rem 0;
    padding-left: 2.5rem;
    position: relative;
    color: var(--text-primary);
    font-size: 1.05rem;
    line-height: 1.7;
    border-bottom: 1px solid rgba(226, 232, 240, 0.5);
}

.section li:last-child {
    border-bottom: none;
}

.section li:before {
    content: '▶';
    color: var(--accent-color);
    position: absolute;
    left: 1rem;
    font-weight: bold;
    font-size: 0.8rem;
}

/* Info Sections */
.info-section {
    background: linear-gradient(135deg, var(--panel-bg) 0%, var(--panel-bg-2) 100%);
    border-radius: 16px;
    box-shadow: var(--content-shadow-lg);
    margin: 3rem 0;
    padding: 3.5rem;
    border: 1px solid var(--panel-border);
    position: relative;
}

.info-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--success-color) 0%, var(--accent-color) 100%);
    border-radius: 16px 16px 0 0;
}

.info-section h2 {
    color: var(--primary-color);
    margin-bottom: 2rem;
    font-size: 2rem;
    font-weight: 700;
    padding-bottom: 1rem;
    border-bottom: 3px solid var(--border-color);
    position: relative;
}

.info-section h2::after {
    content: '';
    position: absolute;
    bottom: -3px;
    left: 0;
    width: 80px;
    height: 3px;
    background: var(--accent-color);
}

.info-section h3 {
    color: var(--secondary-color);
    margin: 2.5rem 0 1.5rem 0;
    font-size: 1.375rem;
    font-weight: 600;
}

.info-section ul {
    margin: 1.5rem 0;
    padding-left: 0;
}

.info-section li {
    margin: 1rem 0;
    line-height: 1.7;
    color: var(--text-primary);
    padding-left: 2rem;
    position: relative;
    font-size: 1.05rem;
}


/* Footer */
.footer {
    background: linear-gradient(135deg, var(--dark-color, #1e293b) 0%, #0f172a 100%);
    color: white;
    text-align: center;
    padding: 4rem 0;
    margin-top: 5rem;
    position: relative;
}

.footer::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: 'data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><defs><pattern id="footerPattern" width="40" height="40" patternUnits="userSpaceOnUse"><circle cx="20" cy="20" r="1" fill="white" opacity="0.05"/></pattern></defs><rect width="100" height="100" fill="url(%23footerPattern"/></svg>';
    pointer-events: none;
}

.footer a {
    color: var(--accent-color);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
}

.footer a:hover {
    text-decoration: underline;
    color: #60a5fa;
}

/* Responsive */
@media (max-width: 768px) {
    .container {
        padding: 2rem 1rem;
    }
    
    .header {
        padding: 5rem 0 2rem;
        position: relative;
    }
    
    .header h1 {
        font-size: 2.25rem;
        color: white !important;
    }
    
    .c-btn {
        position: absolute;
        top: 0.5rem;
        right: 1rem;
        margin: 0;
        z-index: 10;
    }
    
    .nav-container {
        flex-direction: column;
        gap: 0;
    }
    
    .nav a {
        padding: 1.25rem 1.5rem;
        text-align: center;
        border-bottom: 1px solid var(--border-color);
        border-left: 3px solid transparent;
    }
    
    .nav a.active {
        border-left-color: var(--primary-color);
        border-bottom-color: var(--border-color);
    }
    
    .article-header {
        padding: 3rem 2rem;
    }
    
    .article-content {
        padding: 3rem 2rem;
    }
    
    .info-section {
        padding: 2.5rem 2rem;
    }
    
    .article-title {
        font-size: 2rem;
    }
    
    .section h3 {
        font-size: 1.375rem;
    }
    
    .info-section h2 {
        font-size: 1.75rem;
    }
    
    .ad-container {
        margin: 1.5rem 0 !important;
        padding: 1rem !important;
    }
}

/* Utility classes */
.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;
}

/* Ad container styling to match theme */
.ad-container {
    margin: 2rem 0 !important;
    text-align: center;
    border: 1px solid var(--panel-border) !important;
    border-radius: 12px !important;
    padding: 1.5rem !important;
    background: linear-gradient(135deg, var(--ad-bg) 0%, var(--ad-bg-2) 100%) !important;
    box-shadow: var(--content-shadow);
    color: var(--content-text);
}

.ad-label {
    display: block;
    font-size: 0.75rem !important;
    color: var(--ad-label) !important;
    margin-bottom: 1rem !important;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-weight: 600;
}

.ad-unit {
    margin: 0 auto;
}

/* Enhanced visual elements */
.fade-in {
    animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* Improved spacing and visual hierarchy */
.article-content > *:first-child {
    margin-top: 0;
}

.article-content > *:last-child {
    margin-bottom: 0;
}

.article-navigation {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin: 2rem 0;
    gap: 1rem;
}

.top-navigation {
    margin-bottom: 2rem;
}

.bottom-navigation {
    margin-top: 3rem;
}

.nav-button {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    background: var(--surface-color);
    border: 2px solid var(--border-color);
    border-radius: 8px;
    color: var(--text-primary);
    font-weight: 600;
    font-size: 0.9rem;
    cursor: pointer;
    transition: all 0.3s ease;
    text-decoration: none;
    box-shadow: var(--shadow-sm);
}

.nav-button:hover {
    background: var(--primary-color);
    color: var(--light-color);
    border-color: var(--primary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.nav-button:active {
    transform: translateY(0);
    box-shadow: var(--shadow-sm);
}

.prev-button {
    margin-right: auto;
}

.next-button {
    margin-left: auto;
}

.button-icon {
    font-weight: bold;
    font-size: 1.1rem;
}

/* Responsive design for mobile */
@media (max-width: 768px) {
    .article-navigation {
        flex-direction: column;
        gap: 1rem;
    }
    
    .nav-button {
        width: 100%;
        justify-content: center;
    }
    
    .prev-button, .next-button {
        margin: 0;
    }
}

/* Ensure buttons are properly spaced when only one is visible */
.article-navigation:has(.prev-button:only-child) .prev-button,
.article-navigation:has(.next-button:only-child) .next-button {
    margin: 0 auto;
}

.onclickthingy {
    cursor: pointer;
    transition: color 0.3s ease;
}

.onclickthingy:hover {
    color: #f59e0b;
}

/* External navigation links styling */
.external-nav-link {
    color: var(--content-primary) !important;
    transition: color 0.3s ease;
    font-weight: 500;
}

.external-nav-link:hover {
    color: var(--content-tertiary) !important;
    text-decoration: underline;
}

/* Ensure proper contrast in both themes */
:root .external-nav-link {
    color: #1e40af !important; /* Dark blue for light mode */
}

[data-theme="dark"] .external-nav-link, 
.theme-dark .external-nav-link {
    color: #60a5fa !important; /* Light blue for dark mode */
}

[data-theme="dark"] .external-nav-link:hover, 
.theme-dark .external-nav-link:hover {
    color: #93c5fd !important;
}