:root {
    --primary-color: #0d6efd;
    --secondary-color: #6c757d;
    --dark-color: #212529;
    --light-color: #f8f9fa;
    --success-color: #198754;
    --danger-color: #dc3545;
    --warning-color: #ffc107;
    --info-color: #0dcaf0;
}

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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--dark-color);
}

/* Typography */
h1, h2, h3, h4, h5, h6 {
    font-weight: 600;
    line-height: 1.3;
}

/* Hero Section */
.hero-section {
    background: linear-gradient(135deg, var(--dark-color) 0%, var(--primary-color) 100%);
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    overflow: hidden;
}

.hero-section::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="grid" width="10" height="10" patternUnits="userSpaceOnUse"><path d="M 10 0 L 0 0 0 10" fill="none" stroke="rgba(255,255,255,0.1)" stroke-width="0.5"/></pattern></defs><rect width="100" height="100" fill="url(%23grid)"/></svg>');
    opacity: 0.3;
}

.hero-section .container {
    position: relative;
    z-index: 2;
}

/* Physics Animation */
.physics-animation {
    animation: float 6s ease-in-out infinite;
}

@keyframes float {
    0%, 100% { transform: translateY(0px) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(180deg); }
}

/* Cards */
.card {
    border-radius: 15px;
    transition: all 0.3s ease;
    border: none;
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(0,0,0,0.15) !important;
}

/* Feature Icons */
.feature-icon {
    transition: transform 0.3s ease;
}

.card:hover .feature-icon {
    transform: scale(1.1);
}

/* Physics Branches */
.physics-branch {
    background: rgba(255, 255, 255, 0.8);
    border-radius: 15px;
    transition: all 0.3s ease;
    border: 2px solid transparent;
}

.physics-branch:hover {
    background: white;
    border-color: var(--primary-color);
    transform: translateY(-5px);
    box-shadow: 0 10px 25px rgba(13, 110, 253, 0.15);
}

/* Navigation */
.navbar-brand {
    font-size: 1.5rem;
}

.navbar-nav .nav-link {
    font-weight: 500;
    transition: color 0.3s ease;
}

.navbar-nav .nav-link:hover {
    color: var(--primary-color) !important;
}

/* Buttons */
.btn {
    border-radius: 10px;
    font-weight: 500;
    padding: 12px 30px;
    transition: all 0.3s ease;
}

.btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.2);
}

.btn-primary {
    background: linear-gradient(45deg, var(--primary-color), #0056b3);
    border: none;
}

.btn-outline-light:hover {
    background: rgba(255, 255, 255, 0.1);
    border-color: white;
}

/* Footer */
footer {
    background: var(--dark-color) !important;
}

.social-links a {
    transition: color 0.3s ease;
}

.social-links a:hover {
    color: var(--primary-color) !important;
}

/* Contact Info */
.contact-info p {
    margin-bottom: 0.5rem;
}

.contact-info a:hover {
    color: var(--primary-color) !important;
}

/* Responsive Design */
@media (max-width: 768px) {
    .hero-section {
        text-align: center;
        padding: 2rem 0;
    }
    
    .display-4 {
        font-size: 2.5rem;
    }
    
    .physics-animation {
        margin-top: 2rem;
    }
    
    .physics-animation i {
        font-size: 4rem !important;
    }
}

/* Smooth Scrolling */
html {
    scroll-behavior: smooth;
}

/* Loading Animation */
.loading {
    opacity: 0;
    animation: fadeIn 1s ease-in forwards;
}

@keyframes fadeIn {
    to {
        opacity: 1;
    }
}

/* Form Styles */
.form-control {
    border-radius: 10px;
    border: 2px solid #e9ecef;
    padding: 12px 15px;
    transition: all 0.3s ease;
}

.form-control:focus {
    border-color: var(--primary-color);
    box-shadow: 0 0 0 0.2rem rgba(13, 110, 253, 0.25);
}

/* Section Spacing */
section {
    padding: 5rem 0;
}

@media (max-width: 768px) {
    section {
        padding: 3rem 0;
    }
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: #f1f1f1;
}

::-webkit-scrollbar-thumb {
    background: var(--primary-color);
    border-radius: 4px;
}

::-webkit-scrollbar-thumb:hover {
    background: #0056b3;
}