:root {
    --primary: #2563eb;
    --dark: #0f172a;
    --text: #334155;
    --border: #e2e8f0;
    --light-bg: #f8fafc;
}

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

body {
    font-family: 'Inter', -apple-system, sans-serif;
    color: var(--text);
    line-height: 1.6;
    background: #ffffff;
    -webkit-font-smoothing: antialiased;
}

.container { 
    max-width: 1000px; 
    margin: 0 auto; 
    padding: 0 1.5rem; 
}

/* --- RESPONSIVE NAVIGATION --- */
nav { 
    padding: 1rem 0; 
    border-bottom: 1px solid var(--border); 
    background: #fff;
    sticky: top;
    z-index: 100;
}

nav .container { 
    display: flex; 
    flex-direction: column; /* Stack on mobile */
    align-items: center;
    gap: 1rem;
}

.logo { font-size: 1.5rem; font-weight: 800; color: var(--dark); text-decoration: none; }
.logo span { color: var(--primary); }

.nav-links { 
    list-style: none; 
    display: flex; 
    gap: 1rem; 
    font-size: 0.9rem;
}

/* Desktop Navigation Adjustment */
@media (min-width: 768px) {
    nav .container { flex-direction: row; justify-content: space-between; }
    .nav-links { gap: 2rem; font-size: 1rem; }
}

.nav-links a { text-decoration: none; color: var(--text); font-weight: 500; transition: 0.2s; }
.nav-links a.active { color: var(--primary); font-weight: 700; }

/* --- RESPONSIVE TYPOGRAPHY --- */
h1 { 
    font-size: 2rem; /* Smaller for mobile */
    color: var(--dark); 
    margin: 2rem 0 1rem; 
    line-height: 1.2; 
}

@media (min-width: 768px) {
    h1 { font-size: 3rem; } /* Larger for desktop */
}

/* --- RESPONSIVE GRID --- */
.grid { 
    display: grid; 
    grid-template-columns: 1fr; /* 1 column on mobile */
    gap: 1.5rem; 
    margin: 2rem 0; 
}

@media (min-width: 768px) {
    .grid { grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); } /* Side-by-side on desktop */
}

/* Card Styling */
.card {
    border: 1px solid var(--border);
    padding: 2rem;
    border-radius: 12px;
    background: var(--light-bg);
}

.btn { 
    display: block; 
    text-align: center;
    padding: 0.8rem 1.6rem; 
    border-radius: 8px; 
    text-decoration: none; 
    font-weight: 600; 
    background: var(--primary); 
    color: white;
}

footer { padding: 3rem 0; border-top: 1px solid var(--border); text-align: center; color: #94a3b8; font-size: 0.8rem; }