/* CSS Variables for Theme Support */
:root {
    /* Dark theme (default) */
    --bg-primary: #1C1C1E;
    --bg-secondary: #2C2C2E;
    --bg-tertiary: #3A3A3C;
    --bg-quaternary: #48484A;
    --text-primary: #FFFFFF;
    --text-secondary: #8E8E93;
    --text-accent: #f5d762;
    --accent-primary: #0A84FF;
    --accent-primary-hover: #0066CC;
    --accent-secondary: #2cb833;
    --accent-secondary-hover: #259c2b;
    --accent-success: #30D158;
    --accent-error: #FF453A;
    --border-primary: #3A3A3C;
    --border-focus: #007AFF;
}

/* Light theme */
[data-theme="light"] {
    --bg-primary: #FFFFFF;
    --bg-secondary: #F2F2F7;
    --bg-tertiary: #E5E5EA;
    --bg-quaternary: #D1D1D6;
    --text-primary: #000000;
    --text-secondary: #6D6D70;
    --text-accent: #B8860B;
    --accent-primary: #007AFF;
    --accent-primary-hover: #0056CC;
    --accent-secondary: #68de59;
    --accent-secondary-hover: #53b547;
    --accent-success: #28A745;
    --accent-error: #DC3545;
    --border-primary: #C7C7CC;
    --border-focus: #007AFF;
}

/* Reset and Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background-color: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    overflow-x: hidden;
    transition: background-color 0.3s ease, color 0.3s ease;
}

/* Main Container */
.main-container {
    max-width: 700px;
    margin: 0 auto;
    padding: 25px 30px;
    min-height: 100vh;
}

/* Title Section */
.title-section {
    text-align: center;
    margin-bottom: 30px;
}

.title-header {
    display: flex;
    justify-content: center;
    align-items: center;
    position: relative;
    margin-bottom: 5px;
}

.title {
    font-family: 'Londrina Shadow';
    font-size: 40px;
    font-weight: 400;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.title-link {
    color: inherit;
    text-decoration: none;
    display: inline-block;
    transition: none;
}

.title-link:hover,
.title-link:active,
.title-link:visited {
    color: inherit;
    text-decoration: none;
}

.title-emoji {
  font-size: 20px;
}

.theme-toggle {
    position: absolute;
    right: 0;
    background: var(--bg-secondary);
    border: 1px solid var(--border-primary);
    border-radius: 8px;
    padding: 8px 12px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 16px;
}

.theme-toggle:hover {
    background: var(--bg-tertiary);
    transform: scale(1.05);
}

.theme-toggle:active {
    transform: scale(0.95);
}

.theme-icon {
    display: inline-block;
    transition: transform 0.3s ease;
}

.subtitle {
    font-size: 14px;
    color: var(--text-secondary);
    font-weight: 400;
}

/* Card Styles */
.card {
    background-color: var(--bg-secondary);
    border-radius: 12px;
    margin-bottom: 20px;
    overflow: hidden;
    transition: background-color 0.3s ease;
}

.card-header {
    padding: 20px 20px 0 20px;
}

.card-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 2px;
}

.card-subtitle {
    font-size: 12px;
    color: var(--text-secondary);
    margin-bottom: 15px;
}

/* Card Content Styles */
.card-content {
    padding: 0 20px 20px 20px;
}

.card-content p {
    margin-bottom: 15px;
    color: var(--text-primary);
    font-size: 14px;
    line-height: 1.7;
}

.card-content h3 {
    font-size: 15px;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: 20px;
    margin-bottom: 10px;
}

.card-content h4 {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-primary);
    margin-top: 15px;
    margin-bottom: 8px;
}

.card-content ul,
.card-content ol {
    margin-left: 20px;
    margin-bottom: 15px;
    color: var(--text-primary);
}

.card-content li {
    margin-bottom: 8px;
    font-size: 14px;
    line-height: 1.6;
}

.card-content a {
    color: var(--accent-primary);
    text-decoration: none;
    transition: color 0.2s ease;
}

.card-content a:hover {
    color: var(--accent-primary-hover);
    text-decoration: underline;
}

.card-content strong {
    font-weight: 600;
    color: var(--text-primary);
}

.card-content em {
    font-style: italic;
    color: var(--text-secondary);
}

.card-content code {
    background-color: var(--bg-primary);
    border: 1px solid var(--border-primary);
    border-radius: 4px;
    padding: 2px 6px;
    font-family: 'SF Mono', Monaco, 'Cascadia Code', 'Roboto Mono', Consolas, monospace;
    font-size: 12px;
    color: var(--text-accent);
}

.card-content blockquote {
    border-left: 3px solid var(--accent-primary);
    padding-left: 15px;
    margin-left: 0;
    margin-bottom: 15px;
    color: var(--text-secondary);
    font-style: italic;
}

.card-content hr {
    border: none;
    border-top: 1px solid var(--border-primary);
    margin: 20px 0;
}

/* Bottom Navigation */
.bottom-nav {
    text-align: center;
    padding: 20px 0;
    margin-top: 30px;
    border-top: 1px solid var(--border-primary);
}

.nav-link {
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 13px;
    font-weight: 500;
    transition: color 0.2s ease;
    padding: 0 8px;
}

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

.nav-separator {
    color: var(--text-secondary);
    font-size: 13px;
    padding: 0 4px;
}

/* Footer Section */
.footer {
    text-align: center;
    padding: 20px 0;
    margin-top: 0;
    border-top: 1px solid var(--border-primary);
}

.footer-text {
    font-size: 12px;
    color: var(--text-secondary);
    font-weight: 400;
}

/* Responsive Design */
@media (max-width: 768px) {
    .main-container {
        padding: 20px 20px;
        max-width: 100%;
    }

    .title {
        font-size: 24px;
    }

    .card-header,
    .card-content {
        padding-left: 15px;
        padding-right: 15px;
    }

    .nav-link {
        font-size: 12px;
        padding: 0 6px;
    }

    .nav-separator {
        font-size: 12px;
        padding: 0 3px;
    }
}

@media (max-width: 768px) {
    .nav-link {
        font-size: 12px;
        padding: 0 6px;
    }

    .nav-separator {
        font-size: 12px;
        padding: 0 3px;
    }
}

@media (max-width: 480px) {
    .main-container {
        padding: 15px;
    }

    .card-header {
        padding: 15px 15px 0 15px;
    }

    .card-content {
        padding: 0 15px 15px 15px;
    }

    .card-content p,
    .card-content li {
        font-size: 13px;
    }
}

/* Selection Colors */
::selection {
    background-color: var(--border-focus);
    color: var(--bg-primary);
}

::-moz-selection {
    background-color: var(--border-focus);
    color: var(--bg-primary);
}

/* Focus states for accessibility */
.theme-toggle:focus-visible {
    outline: 2px solid var(--border-focus);
    outline-offset: 2px;
}