/* CSS Variables */
:root {
    --primary-color: #0f172a;
    --secondary-color: #334155;
    --accent-color: #2563eb;
    --accent-hover: #1d4ed8;
    --bg-light: #f8fafc;
    --bg-white: #ffffff;
    --text-main: #1e293b;
    --text-muted: #64748b;
    --border-color: #e2e8f0;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    scroll-behavior: smooth;
}

body {
    background-color: var(--bg-light);
    color: var(--text-main);
    line-height: 1.6;
}

.container {
    width: 90%;
    max-width: 1200px;
    margin: 0 auto;
}

/* Typography */
h1, h2, h3, h4 { color: var(--primary-color); }
p { color: var(--text-muted); }
a { text-decoration: none; color: inherit; }

/* Navbar */
.navbar {
    background: var(--bg-white);
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
    position: fixed;
    top: 0;
    width: 100%;
    z-index: 1000;
    transition: 0.3s;
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
}

.logo {
    font-size: 24px;
    font-weight: bold;
    color: var(--primary-color);
}
.logo span { color: var(--accent-color); }

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    font-weight: 500;
    transition: color 0.3s ease;
}

.nav-links a:hover {
    color: var(--accent-color);
}

.hamburger {
    display: none;
    font-size: 24px;
    cursor: pointer;
}

/* Hero Section */
.hero {
    padding: 150px 0 100px;
    background: linear-gradient(135deg, var(--bg-light) 0%, #e0e7ff 100%);
    min-height: 80vh;
    display: flex;
    align-items: center;
}

.hero h3 { font-size: 24px; font-weight: 400; color: var(--text-muted); margin-bottom: 10px;}
.hero h1 { font-size: 56px; font-weight: 800; margin-bottom: 10px; }
.hero h2 { font-size: 32px; margin-bottom: 20px; }
.hero h2 span { color: var(--accent-color); }
.hero p { font-size: 18px; max-width: 600px; margin-bottom: 30px; }

.btn {
    padding: 12px 28px;
    border-radius: 6px;
    font-weight: 600;
    display: inline-block;
    transition: 0.3s;
}

.btn-primary {
    background: var(--accent-color);
    color: white;
    border: 2px solid var(--accent-color);
}
.btn-primary:hover { background: var(--accent-hover); }

.btn-secondary {
    background: transparent;
    color: var(--primary-color);
    border: 2px solid var(--primary-color);
    margin-left: 15px;
}
.btn-secondary:hover {
    background: var(--primary-color);
    color: white;
}

/* Sections */
section { padding: 80px 0; }
.section-title {
    text-align: center;
    font-size: 36px;
    margin-bottom: 50px;
    position: relative;
}
.section-title::after {
    content: '';
    display: block;
    width: 60px;
    height: 4px;
    background: var(--accent-color);
    margin: 15px auto 0;
    border-radius: 2px;
}

/* Skills Grid */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}
.skill-card {
    background: var(--bg-white);
    padding: 30px;
    border-radius: 12px;
    text-align: center;
    box-shadow: 0 4px 6px rgba(0,0,0,0.05);
    border: 1px solid var(--border-color);
    transition: transform 0.3s ease;
}
.skill-card:hover { transform: translateY(-5px); }
.skill-card .icon {
    font-size: 40px;
    color: var(--accent-color);
    margin-bottom: 20px;
}
.skill-card h3 { margin-bottom: 15px; }

/* Projects */
.category-title {
    font-size: 24px;
    margin: 40px 0 20px;
    border-left: 4px solid var(--accent-color);
    padding-left: 15px;
}
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}
.project-card {
    background: var(--bg-white);
    border-radius: 12px;
    overflow: hidden;
    box-shadow: 0 4px 10px rgba(0,0,0,0.05);
    transition: 0.3s;
}
.project-card:hover {
    box-shadow: 0 10px 20px rgba(0,0,0,0.1);
}
.project-img {
    height: 200px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-weight: bold;
    font-size: 20px;
    text-shadow: 1px 1px 4px rgba(0,0,0,0.6);
}
.civil3d-bg { background: linear-gradient(45deg, #1d4ed8, #60a5fa); }
.sap-bg { background: linear-gradient(45deg, #b91c1c, #f87171); }
.plaxis-bg { background: linear-gradient(45deg, #047857, #34d399); }
.gis-bg { background: linear-gradient(45deg, #b45309, #fbbf24); }
.supervise-bg { background: linear-gradient(45deg, #4338ca, #818cf8); }

.project-info { padding: 20px; }
.project-info h4 { margin-bottom: 10px; font-size: 18px; }

/* Footer */
.footer {
    background: var(--primary-color);
    color: white;
    text-align: center;
    padding: 60px 0 30px;
}
.footer h2 { color: white; margin-bottom: 15px; }
.footer p { color: #cbd5e1; margin-bottom: 30px; }
.contact-info {
    display: flex;
    justify-content: center;
    gap: 30px;
    margin-bottom: 40px;
    flex-wrap: wrap;
}
.contact-info a {
    color: white;
    font-size: 18px;
    display: flex;
    align-items: center;
    gap: 10px;
}
.contact-info a:hover { color: #93c5fd; }
.copyright { font-size: 14px; border-top: 1px solid #334155; padding-top: 20px; }

/* Responsive */
@media (max-width: 768px) {
    .nav-links { display: none; }
    .hamburger { display: block; }
    .hero h1 { font-size: 40px; }
    .contact-info { flex-direction: column; gap: 15px; align-items: center; }
    .btn-secondary { margin-left: 0; margin-top: 15px; display: block; width: 100%; text-align: center; }
    .btn-primary { display: block; width: 100%; text-align: center; }
}