:root {
    --primary-blue: #2563eb;
    --dark-blue: #1e40af;
    --light-blue: #dbeafe;
    --text-dark: #1e293b;
    --text-light: #f8fafc;
    --background: #f8fafc;
    --surface: #ffffff;
    --muted: #64748b;
    --shadow: rgba(15, 23, 42, 0.08);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', sans-serif;
}

body {
    background-color: var(--background);
    color: var(--text-dark);
    line-height: 1.6;
}

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

.portfolio-header {
    text-align: center;
    padding: 120px 20px 80px;
    background: linear-gradient(135deg, var(--primary-blue), var(--dark-blue));
    color: var(--text-light);
}

.portfolio-header h1 {
    font-size: clamp(2.2rem, 4vw, 3.2rem);
    margin-bottom: 1rem;
}

.portfolio-header p {
    max-width: 700px;
    margin: 0 auto;
    color: rgba(255, 255, 255, 0.9);
    font-size: 1.08rem;
}

.project-filters {
    display: flex;
    gap: 15px;
    justify-content: center;
    margin: 40px 0 24px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 10px 22px;
    border: 2px solid var(--primary-blue);
    background: var(--surface);
    color: var(--text-dark);
    border-radius: 30px;
    cursor: pointer;
    transition: all 0.3s ease;
    font-weight: 600;
}

.filter-btn.active,
.filter-btn:hover {
    background: var(--primary-blue);
    color: var(--text-light);
    box-shadow: 0 8px 16px rgba(37, 99, 235, 0.18);
}

.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
    padding: 40px 0 60px;
}

.project-card {
    background: var(--surface);
    border-radius: 16px;
    overflow: hidden;
    transform: translateY(18px);
    opacity: 0;
    transition: all 0.5s ease;
    box-shadow: 0 10px 24px var(--shadow);
    border: 1px solid rgba(148, 163, 184, 0.2);
}

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

.project-image {
    height: 250px;
    overflow: hidden;
    position: relative;
}

.project-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.3s ease;
}

.project-card:hover .project-image img {
    transform: scale(1.06);
}

.project-info {
    padding: 25px;
    color: var(--text-dark);
}

.project-info h3 {
    color: var(--dark-blue);
    margin-bottom: 0.75rem;
}

.project-tags {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin: 12px 0 16px;
}

.project-tag {
    background: var(--light-blue);
    color: var(--dark-blue);
    padding: 5px 12px;
    border-radius: 20px;
    font-size: 0.8rem;
    font-weight: 600;
}

.project-links {
    margin-top: 18px;
    display: flex;
    gap: 15px;
    flex-wrap: wrap;
}

.project-link {
    color: var(--primary-blue);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    transition: color 0.3s ease, opacity 0.3s ease;
    font-weight: 600;
}

.project-link:hover {
    color: var(--dark-blue);
    opacity: 0.9;
}

@media (max-width: 768px) {
    .projects-grid {
        grid-template-columns: 1fr;
    }

    .project-filters {
        gap: 10px;
    }
}