:root {
    --bg-primary: #1a202c;
    --text-primary: #ffffff;
}

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

/* Theme transitions */
body {
    transition: background-color 0.3s, color 0.3s;
}

/* Dark mode */
body.dark-mode {
    background-color: var(--bg-primary);
    color: var(--text-primary);
}

/* Light mode */
body.light-mode {
    background-color: var(--bg-primary);
    color: var(--text-primary);
}

/* 3D Card effect */
.card-3d {
    transform-style: preserve-3d;
    transition: transform 0.3s ease;
}

.card-3d:hover {
    transform: translateY(-10px) rotateX(5deg);
}

/* Animated underline for links */
.nav-link {
    position: relative;
    text-decoration: none;
}

.nav-link::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -2px;
    left: 0;
    background-color: #3182ce;
    transition: width 0.3s ease;
}

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

/* Skills icons animation */
.skill-icon {
    transition: transform 0.3s ease;
}

.skill-icon:hover {
    transform: scale(1.2) rotate(10deg);
}

/* Project card hover effect */
.project-card {
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(0, 0, 0, 0.2);
}

/* Review card animation */
.review-card {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.5s ease, transform 0.5s ease;
}

.review-card.visible {
    opacity: 1;
    transform: translateY(0);
}

/* Contact form animation */
.form-input {
    transition: border-color 0.3s ease, box-shadow 0.3s ease;
}

.form-input:focus {
    border-color: #3182ce;
    box-shadow: 0 0 0 3px rgba(49, 130, 206, 0.3);
}

/* Mobile menu animation */
.mobile-menu {
    transition: transform 0.3s ease;
}

.mobile-menu.open {
    transform: translateX(0);
}

/* Responsive design */
@media (max-width: 768px) {
    .container {
        padding: 0 1rem;
    }
    
    .grid {
        grid-template-columns: 1fr;
    }
}

/* Loading animation */
.loading {
    animation: spin 1s linear infinite;
}

@keyframes spin {
    from {
        transform: rotate(0deg);
    }
    to {
        transform: rotate(360deg);
    }
}