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

:root {
    --primary: #1e4e9c;
    --secondary: #337cf2;
    --accent: #00d4ff;
    --text-dark: #1a1a1a;
    --text-light: #6b7280;
    --bg-light: #f8fafc;
    --white: #ffffff;
    --gradient: linear-gradient(135deg, var(--primary) 0%, var(--secondary) 50%, var(--accent) 100%);
    --shadow: 0 10px 30px rgba(30, 78, 156, 0.1);
    --shadow-hover: 0 20px 40px rgba(30, 78, 156, 0.15);
    --border-radius: 20px;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    line-height: 1.7;
    color: var(--text-dark);
    background: var(--bg-light);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* Navigation */
.navbar {
    position: sticky;
    top: 0;
    background: rgba(255, 255, 255, 0.98);
    backdrop-filter: blur(20px);
    z-index: 1000;
    padding: 1rem 0;
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.05);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--text-dark);
    text-decoration: none;
    transition: transform 0.3s ease;
}

.logo:hover {
    transform: scale(1.05);
}

.logo-accent {
    color: var(--primary);
}

.nav-links {
    display: flex;
    gap: 2rem;
    list-style: none;
    align-items: center;
}

.nav-links a {
    text-decoration: none;
    color: var(--text-dark);
    font-weight: 500;
    transition: all 0.3s ease;
    position: relative;
    padding: 0.5rem 1rem;
    border-radius: 25px;
}

.nav-links a.active {
    background: var(--gradient);
    color: white;
    transform: translateY(-2px);
}

.nav-links a:not(.active)::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 2px;
    background: var(--gradient);
    transition: width 0.3s ease;
}

.nav-links a:not(.active):hover::after {
    width: 80%;
}

/* Header Section */
.page-header {
    background: var(--gradient);
    padding: 4rem 0 2rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

.page-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('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="rgba(255,255,255,0.1)"/></pattern></defs><rect width="100%" height="100%" fill="url(%23dots)"/></svg>');
    opacity: 0.3;
}

.page-header-content {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    position: relative;
    z-index: 1;
}

.page-header h1 {
    font-size: clamp(2.5rem, 5vw, 3.5rem);
    font-weight: 800;
    color: white;
    margin-bottom: 1rem;
    text-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

.page-header p {
    font-size: 1.25rem;
    color: rgba(255, 255, 255, 0.9);
    max-width: 600px;
    margin: 0 auto;
    font-weight: 300;
}

.header-icon {
    display: inline-block;
    font-size: 3rem;
    margin-bottom: 1rem;
    color: rgba(255, 255, 255, 0.8);
}

/* Main Content (List page) */
.main-content {
    flex: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 3rem 2rem;
    width: 100%;
}

/* Newsletter Grid */
.newsletters-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 2rem;
    margin-top: 2rem;
}

.newsletter-card {
    background: white;
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow);
    border: 1px solid rgba(30, 78, 156, 0.05);
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.newsletter-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient);
}

.newsletter-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}

.newsletter-header {
    display: flex;
    align-items: flex-start;
    gap: 1rem;
    margin-bottom: 1rem;
}

.newsletter-icon {
    width: 50px;
    height: 50px;
    background: var(--gradient);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.25rem;
    flex-shrink: 0;
}

.newsletter-info h2 {
    font-size: 1.375rem;
    font-weight: 600;
    color: var(--text-dark);
    margin-bottom: 0.5rem;
    line-height: 1.4;
}

.newsletter-info h2 a {
    color: inherit;
    text-decoration: none;
    transition: color 0.3s ease;
}

.newsletter-info h2 a:hover {
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.newsletter-date {
    color: var(--text-light);
    font-size: 0.875rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.newsletter-excerpt {
    color: var(--text-light);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
    line-height: 1.6;
}

.read-more-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    background: var(--gradient);
    color: white;
    text-decoration: none;
    padding: 0.75rem 1.5rem;
    border-radius: 25px;
    font-weight: 500;
    transition: all 0.3s ease;
    font-size: 0.875rem;
}

.read-more-btn:hover {
    transform: translateX(5px);
    box-shadow: 0 5px 15px rgba(30, 78, 156, 0.3);
}

/* Empty State */
.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    background: white;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    border: 1px solid rgba(30, 78, 156, 0.05);
}

.empty-icon {
    font-size: 4rem;
    color: var(--text-light);
    margin-bottom: 1.5rem;
    opacity: 0.5;
}

.empty-state h3 {
    font-size: 1.5rem;
    color: var(--text-dark);
    margin-bottom: 1rem;
}

.empty-state p {
    color: var(--text-light);
    font-size: 1.125rem;
    max-width: 400px;
    margin: 0 auto 2rem;
}

.subscribe-prompt {
    background: var(--gradient);
    color: white;
    text-decoration: none;
    padding: 1rem 2rem;
    border-radius: 25px;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    transition: all 0.3s ease;
}

.subscribe-prompt:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

/* Footer (list page) */
.footer {
    background: var(--text-dark);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: auto;
}

.footer p {
    opacity: 0.8;
}

/* Mobile Styles (list page) */
@media (max-width: 768px) {
    .nav-container {
        padding: 0 1rem;
    }

    .nav-links {
        gap: 1rem;
    }

    .nav-links a {
        padding: 0.5rem 0.75rem;
        font-size: 0.875rem;
    }

    .page-header {
        padding: 3rem 0 1.5rem;
    }

    .main-content {
        padding: 2rem 1rem;
    }

    .newsletters-grid {
        grid-template-columns: 1fr;
        gap: 1.5rem;
    }

    .newsletter-card {
        padding: 1.5rem;
    }

    .newsletter-header {
        flex-direction: column;
        align-items: center;
        text-align: center;
        gap: 1rem;
    }

    .empty-state {
        padding: 3rem 1.5rem;
    }
}

/* Loading Animation (list page cards) */
@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

.newsletter-card {
    animation: fadeInUp 0.6s ease forwards;
}

.newsletter-card:nth-child(2) { animation-delay: 0.1s; }
.newsletter-card:nth-child(3) { animation-delay: 0.2s; }
.newsletter-card:nth-child(4) { animation-delay: 0.3s; }

/* ----------------------------- */
/* Detail Page Additions (unique) */
/* ----------------------------- */

/* Back Button */
.back-navigation {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem 2rem 0;
}

.back-link {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    color: var(--text-light);
    text-decoration: none;
    font-weight: 500;
    transition: all 0.3s ease;
    padding: 0.75rem 1rem;
    border-radius: 25px;
    background: white;
    box-shadow: var(--shadow);
    border: 1px solid rgba(30, 78, 156, 0.05);
}

.back-link:hover {
    color: var(--primary);
    transform: translateX(-5px);
    box-shadow: var(--shadow-hover);
}

.back-link i {
    transition: transform 0.3s ease;
}

.back-link:hover i {
    transform: translateX(-3px);
}

/* Main Content (detail page override) */
.main-content {
    flex: 1;
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem;
    width: 100%;
}

/* Newsletter Header (detail) */
.newsletter-header {
    background: white;
    padding: 3rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
    text-align: center;
    position: relative;
    overflow: hidden;
    border: 1px solid rgba(30, 78, 156, 0.05);
}

.newsletter-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient);
}

.newsletter-icon {
    width: 80px;
    height: 80px;
    background: var(--gradient);
    border-radius: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 2rem;
    margin: 0 auto 1.5rem;
    box-shadow: 0 10px 20px rgba(30, 78, 156, 0.2);
}

.newsletter-header h1 {
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 700;
    color: var(--text-dark);
    margin-bottom: 1rem;
    line-height: 1.3;
}

.newsletter-meta {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 2rem;
    color: var(--text-light);
    font-size: 0.95rem;
    margin-bottom: 1.5rem;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.newsletter-tags {
    display: flex;
    gap: 0.75rem;
    justify-content: center;
    flex-wrap: wrap;
}

.tag {
    background: rgba(30, 78, 156, 0.1);
    color: var(--primary);
    padding: 0.5rem 1rem;
    border-radius: 20px;
    font-size: 0.875rem;
    font-weight: 500;
}

/* Newsletter Content (detail) */
.newsletter-content {
    background: white;
    padding: 3rem;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    border: 1px solid rgba(30, 78, 156, 0.05);
    position: relative;
}

.newsletter-content::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient);
}

/* Typography */
.newsletter-content h1,
.newsletter-content h2,
.newsletter-content h3,
.newsletter-content h4,
.newsletter-content h5,
.newsletter-content h6 {
    color: var(--text-dark);
    font-weight: 600;
    margin-top: 2rem;
    margin-bottom: 1rem;
    line-height: 1.3;
}

.newsletter-content h1 {
    font-size: 2.25rem;
    font-weight: 700;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.newsletter-content h2 {
    font-size: 1.875rem;
    border-bottom: 2px solid rgba(30, 78, 156, 0.1);
    padding-bottom: 0.5rem;
}

.newsletter-content h3 {
    font-size: 1.5rem;
    color: var(--primary);
}

.newsletter-content h4 {
    font-size: 1.25rem;
}

.newsletter-content p {
    margin-bottom: 1.5rem;
    font-size: 1.0625rem;
    line-height: 1.8;
    color: var(--text-dark);
}

.newsletter-content ul,
.newsletter-content ol {
    margin-bottom: 1.5rem;
    padding-left: 2rem;
}

.newsletter-content li {
    margin-bottom: 0.75rem;
    color: var(--text-dark);
    line-height: 1.7;
}

.newsletter-content blockquote {
    background: rgba(30, 78, 156, 0.05);
    border-left: 4px solid var(--primary);
    padding: 1.5rem 2rem;
    margin: 2rem 0;
    border-radius: 0 15px 15px 0;
    font-style: italic;
    color: var(--text-light);
    position: relative;
}

.newsletter-content blockquote::before {
    content: '"';
    font-size: 3rem;
    color: var(--primary);
    position: absolute;
    top: 0.5rem;
    left: 1rem;
    opacity: 0.3;
}

.newsletter-content a {
    color: var(--primary);
    text-decoration: none;
    font-weight: 500;
    border-bottom: 1px solid transparent;
    transition: all 0.3s ease;
}

.newsletter-content a:hover {
    border-bottom-color: var(--primary);
    color: var(--secondary);
}

.newsletter-content img {
    max-width: 100%;
    height: auto;
    border-radius: 15px;
    margin: 2rem 0;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
}

.newsletter-content pre {
    background: #f8fafc;
    border: 1px solid #e5e7eb;
    border-radius: 10px;
    padding: 1.5rem;
    overflow-x: auto;
    margin: 2rem 0;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
}

.newsletter-content code {
    background: rgba(30, 78, 156, 0.1);
    color: var(--primary);
    padding: 0.25rem 0.5rem;
    border-radius: 5px;
    font-family: 'Monaco', 'Menlo', 'Ubuntu Mono', monospace;
    font-size: 0.9em;
}

.newsletter-content table {
    width: 100%;
    border-collapse: collapse;
    margin: 2rem 0;
    border-radius: 10px;
    overflow: hidden;
    box-shadow: 0 5px 15px rgba(0, 0, 0, 0.1);
}

.newsletter-content th,
.newsletter-content td {
    padding: 1rem 1.5rem;
    text-align: left;
    border-bottom: 1px solid rgba(30, 78, 156, 0.1);
}

.newsletter-content th {
    background: var(--gradient);
    color: white;
    font-weight: 600;
}

/* Action Buttons */
.newsletter-actions {
    display: flex;
    gap: 1rem;
    justify-content: center;
    margin: 3rem 0 2rem;
    flex-wrap: wrap;
}

.action-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    padding: 1rem 2rem;
    border: none;
    border-radius: 25px;
    font-weight: 600;
    text-decoration: none;
    cursor: pointer;
    transition: all 0.3s ease;
    font-size: 1rem;
}

.action-btn.primary {
    background: var(--gradient);
    color: white;
}

.action-btn.secondary {
    background: white;
    color: var(--primary);
    border: 2px solid var(--primary);
}

.action-btn:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

/* Footer (detail page override) */
.footer {
    background: var(--text-dark);
    color: white;
    text-align: center;
    padding: 2rem 0;
    margin-top: 2rem;
}

/* Mobile (detail page) */
@media (max-width: 768px) {
    .back-navigation {
        padding: 1.5rem 1rem 0;
    }

    .main-content {
        padding: 1rem;
    }

    .newsletter-header {
        padding: 2rem 1.5rem;
    }

    .newsletter-meta {
        flex-direction: column;
        gap: 1rem;
    }

    .newsletter-content {
        padding: 2rem 1.5rem;
    }

    .newsletter-content h1 { font-size: 1.75rem; }
    .newsletter-content h2 { font-size: 1.5rem; }
    .newsletter-content h3 { font-size: 1.25rem; }

    .newsletter-actions {
        flex-direction: column;
        align-items: center;
    }

    .action-btn {
        width: 100%;
        max-width: 300px;
        justify-content: center;
    }

    .newsletter-content pre {
        padding: 1rem;
        font-size: 0.875rem;
    }

    .newsletter-content th,
    .newsletter-content td {
        padding: 0.75rem 1rem;
        font-size: 0.875rem;
    }
}

@media (max-width: 480px) {
    .newsletter-header {
        padding: 1.5rem 1rem;
    }

    .newsletter-content {
        padding: 1.5rem 1rem;
    }

    .newsletter-icon {
        width: 60px;
        height: 60px;
        font-size: 1.5rem;
    }
}

/* Print Styles */
@media print {
    .navbar,
    .back-navigation,
    .newsletter-actions,
    .footer {
        display: none;
    }

    .newsletter-header,
    .newsletter-content {
        box-shadow: none;
        border: 1px solid #ddd;
    }

    .newsletter-content {
        page-break-inside: avoid;
    }
}

/* Animation (detail page elements) */
.newsletter-header,
.newsletter-content {
    animation: fadeInUp 0.6s ease forwards;
}

.newsletter-content {
    animation-delay: 0.2s;
}