/* --- 1. GLOBAL VARIABLES & RESET --- */
:root {
    /* Light Theme (Default) */
    --bg-color: #f3f4f6;
    --text-color: #1f2937;
    --card-bg: rgba(255, 255, 255, 0.8);
    --primary-color: #6366f1; /* Indigo */
    --primary-hover: #4f46e5;
    --secondary-bg: #e5e7eb;
    --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.05);
    --nav-glass: rgba(255, 255, 255, 0.7);
    --border-color: rgba(0,0,0,0.05);
}

/* Dark Theme Variables */
body.dark-theme {
    --bg-color: #0f172a;
    --text-color: #f3f4f6;
    --card-bg: rgba(30, 41, 59, 0.7);
    --primary-color: #818cf8;
    --primary-hover: #6366f1;
    --secondary-bg: #1e293b;
    --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.3);
    --nav-glass: rgba(15, 23, 42, 0.7);
    --border-color: rgba(255,255,255,0.05);
}

* { margin: 0; padding: 0; box-sizing: border-box; transition: background-color 0.3s ease, color 0.3s ease; }

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* --- 2. NAVIGATION BAR --- */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1.5rem 5%;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 100;
    background: var(--nav-glass);
    backdrop-filter: blur(10px); /* Glass effect */
    border-bottom: 1px solid var(--border-color);
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    letter-spacing: -1px;
    background: linear-gradient(45deg, var(--primary-color), #ec4899);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

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

.nav-links a {
    text-decoration: none;
    color: var(--text-color);
    font-weight: 500;
    font-size: 0.95rem;
    position: relative;
    opacity: 0.8;
    transition: opacity 0.2s;
}

.nav-links a:hover, .nav-links a.active { opacity: 1; }

/* Underline animation for links */
.nav-links a::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -4px;
    left: 0;
    background-color: var(--primary-color);
    transition: width 0.3s ease;
}

.nav-links a:hover::after { width: 100%; }

/* --- 3. THEME TOGGLE BUTTON --- */
.theme-btn {
    background: var(--secondary-bg);
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    border-radius: 50%;
    font-size: 1.2rem;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: var(--shadow-soft);
}

.theme-btn:hover { transform: scale(1.1); }

/* --- 4. HERO SECTION --- */
.hero {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
    padding: 0 20px;
    margin-top: 80px; /* Offset for fixed header */
}

.hero-content h1 {
    font-size: 3.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 1.5rem;
    letter-spacing: -0.03em;
}

.highlight {
    color: var(--primary-color);
}

.hero-content p {
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto 2.5rem auto;
    opacity: 0.8;
}

/* Buttons */
.cta-group { display: flex; gap: 1rem; justify-content: center; }

.btn {
    text-decoration: none;
    padding: 12px 28px;
    border-radius: 8px;
    font-weight: 600;
    transition: transform 0.2s ease, box-shadow 0.2s ease;
}

.btn.primary {
    background-color: var(--primary-color);
    color: white;
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
}

.btn.secondary {
    background-color: var(--secondary-bg);
    color: var(--text-color);
}

.btn:hover { transform: translateY(-2px); box-shadow: 0 6px 20px rgba(0,0,0,0.15); }

/* Background Shapes */
.shape {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    z-index: -1;
    opacity: 0.5;
}

.shape-1 {
    width: 300px; height: 300px;
    background: var(--primary-color);
    top: 10%; left: -100px;
}

.shape-2 {
    width: 400px; height: 400px;
    background: #ec4899; /* Pinkish */
    bottom: 10%; right: -150px;
}

/* Footer */
footer {
    text-align: center;
    padding: 2rem;
    font-size: 0.85rem;
    opacity: 0.6;
}

/* --- 5. ANIMATIONS --- */
@keyframes popIn {
    0% { opacity: 0; transform: scale(0.9); }
    100% { opacity: 1; transform: scale(1); }
}

@keyframes slideUp {
    0% { opacity: 0; transform: translateY(20px); }
    100% { opacity: 1; transform: translateY(0); }
}

.animate-pop-in { animation: popIn 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards; opacity: 0; }
.animate-slide-up { animation: slideUp 0.8s cubic-bezier(0.16, 1, 0.3, 1) forwards; opacity: 0; }

.delay-1 { animation-delay: 0.2s; }
.delay-2 { animation-delay: 0.4s; }