:root {
    --bg-main: #f4fdf8;      
    --surface: #ffffff;
    --text-main: #1e293b;
    --text-muted: #475569;
    --brand-primary: #059669; 
    --brand-dark: #065f46;
    --border-color: #e2e8f0;
    --accent-light: #d1fae5;
    
    --radius-md: 12px;
    --radius-lg: 24px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.1);
    --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
}

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

body {
    font-family: 'Inter', 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-main);
    color: var(--text-main);
    line-height: 1.8;
    -webkit-font-smoothing: antialiased;
}

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

a:hover {
    color: var(--brand-dark);
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* Premium Header */
.site-header {
    background-color: var(--brand-dark);
    color: white;
    padding: 20px 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: var(--shadow-md);
}

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

.site-logo {
    font-size: 1.8rem;
    font-weight: 800;
    color: white !important;
    display: flex;
    align-items: center;
    gap: 12px;
    letter-spacing: -0.5px;
}

.header-nav ul {
    list-style: none;
    display: flex;
    gap: 30px;
    align-items: center;
}

.header-nav a {
    color: #f1f5f9;
    font-weight: 600;
    font-size: 1rem;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.header-nav a:hover {
    color: var(--accent-light);
}

/* Hero Section (Home Page) */
.hero-section {
    background: linear-gradient(135deg, var(--brand-dark) 0%, var(--brand-primary) 100%);
    color: white;
    padding: 80px 20px;
    text-align: center;
    border-radius: 0 0 40px 40px;
    margin-bottom: 50px;
    box-shadow: var(--shadow-md);
}

.hero-title {
    font-size: 3.5rem;
    font-weight: 800;
    margin-bottom: 20px;
    line-height: 1.2;
}

.hero-subtitle {
    font-size: 1.2rem;
    max-width: 800px;
    margin: 0 auto;
    opacity: 0.9;
}

/* Main Content Wrapper */
.site-main {
    padding: 0 0 60px 0;
    min-height: 70vh;
}

/* Homepage Intro Box */
.intro-box {
    background: white;
    padding: 40px;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-sm);
    margin-bottom: 50px;
    border-top: 5px solid var(--brand-primary);
}

.intro-box h2 {
    font-size: 2rem;
    margin-bottom: 20px;
    color: var(--brand-dark);
}

/* Topic Grid */
.grid-heading {
    text-align: center;
    font-size: 2.2rem;
    margin-bottom: 40px;
    color: var(--text-main);
}

.topic-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(350px, 1fr));
    gap: 30px;
}

.topic-card {
    background: var(--surface);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md);
    padding: 30px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    display: flex;
    flex-direction: column;
}

.topic-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
    border-color: var(--brand-primary);
}

.topic-card h3 {
    font-size: 1.3rem;
    margin-bottom: 15px;
    line-height: 1.4;
    border-bottom: 2px solid var(--bg-main);
    padding-bottom: 15px;
}

.topic-card h3 a {
    color: var(--brand-dark);
}

.topic-card p {
    color: var(--text-muted);
    flex-grow: 1;
}

/* Premium Footer */
.site-footer {
    background-color: #0f172a;
    color: #94a3b8;
    padding: 60px 0 20px 0;
}

.footer-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 40px;
    margin-bottom: 40px;
}

.footer-col h4 {
    color: white;
    font-size: 1.2rem;
    margin-bottom: 20px;
}

.footer-col ul {
    list-style: none;
}

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col a {
    color: #94a3b8;
}

.footer-col a:hover {
    color: white;
}

.footer-bottom {
    text-align: center;
    padding-top: 20px;
    border-top: 1px solid #1e293b;
    font-size: 0.9rem;
}

/* Article Styling (The 1000+ words) */
.content-wrapper {
    background: var(--surface);
    padding: 60px;
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-md);
    margin-top: 40px;
}

.article-title {
    font-size: 2.8rem;
    font-weight: 800;
    color: var(--brand-dark);
    margin-bottom: 20px;
    line-height: 1.2;
}

.article-body h2 {
    font-size: 1.8rem;
    color: var(--brand-dark);
    margin-top: 45px;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 2px solid var(--bg-main);
}

.article-body h3 {
    font-size: 1.4rem;
    margin-top: 35px;
    margin-bottom: 15px;
    color: var(--brand-primary);
}

.article-body p {
    margin-bottom: 25px;
    font-size: 1.1rem;
}

.article-body ul, .article-body ol {
    margin-bottom: 25px;
    padding-left: 30px;
    font-size: 1.1rem;
}

.article-body li {
    margin-bottom: 12px;
}

/* The actual "Letter" box format */
.letter-box {
    background-color: #fafaf9;
    border: 1px solid #e7e5e4;
    padding: 40px;
    border-radius: var(--radius-md);
    margin: 35px 0;
    font-family: 'Times New Roman', Times, serif; 
    font-size: 1.2rem;
    color: #1c1917;
    box-shadow: inset 0 2px 4px rgba(0,0,0,0.02);
}

.info-box {
    background-color: var(--accent-light);
    border-left: 5px solid var(--brand-primary);
    padding: 20px 25px;
    margin: 30px 0;
    border-radius: 0 var(--radius-md) var(--radius-md) 0;
    color: var(--brand-dark);
    font-size: 1.05rem;
}

@media (max-width: 768px) {
    .content-wrapper { padding: 30px 20px; }
    .hero-title { font-size: 2.2rem; }
    .header-nav { display: none; } 
    .footer-grid { grid-template-columns: 1fr; }
}