/* Design System for IT Student Portfolio */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

:root {
    /* Color Palette */
    --primary-blue: #007bff;
    --primary-red: #dc3545;
    --dark-blue: #0056b3;
    --dark-red: #c82333;
    --bg-white: #ffffff;
    --text-black: #212529;
    --text-gray: #6c757d;
    --light-gray: #f8f9fa;
    --border-color: #dee2e6;
    
    /* Layout */
    --max-width: 1200px;
    --nav-height: 80px;
    --section-padding: 80px 0;
    
    /* Shadows */
    --shadow-sm: 0 2px 4px rgba(0,0,0,0.05);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.1);
    --shadow-lg: 0 10px 30px rgba(0,0,0,0.15);
    
    /* Transitions */
    --transition-fast: 0.2s ease;
    --transition-slow: 0.4s ease;
}

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

body {
    font-family: 'Inter', sans-serif;
    color: var(--text-black);
    background-color: var(--bg-white);
    line-height: 1.6;
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-fast);
}

ul {
    list-style: none;
}

h1, h2, h3, h4, h5, h6 {
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: 20px;
}

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

/* Sections */
section {
    padding: var(--section-padding);
}

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 2.5rem;
    position: relative;
    display: inline-block;
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 4px;
    background: var(--primary-blue);
    border-radius: 2px;
}

/* Buttons */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: 8px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition-fast);
    border: none;
}

.btn-primary {
    background-color: var(--primary-blue);
    color: white;
}

.btn-primary:hover {
    background-color: var(--dark-blue);
    transform: translateY(-2px);
}

.btn-sec {
    background-color: var(--primary-red);
    color: white;
}

.btn-sec:hover {
    background-color: var(--dark-red);
    transform: translateY(-2px);
}

/* Navbar */
header {
    height: var(--nav-height);
    background: var(--bg-white);
    display: flex;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 1000;
    border-bottom: 1px solid var(--border-color);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    width: 100%;
}

.logo {
    font-size: 1.5rem;
    font-weight: 800;
    color: var(--primary-blue);
}

.logo span {
    color: var(--primary-red);
}

.nav-links {
    display: flex;
    gap: 32px;
}

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

.mobile-menu-btn {
    display: none;
    font-size: 1.5rem;
    cursor: pointer;
}

/* Hero Section */
.hero {
    min-height: calc(100vh - var(--nav-height));
    display: flex;
    align-items: center;
    background: radial-gradient(circle at top right, rgba(0, 123, 255, 0.05), transparent),
                radial-gradient(circle at bottom left, rgba(220, 53, 69, 0.05), transparent);
}

.hero-content {
    max-width: 700px;
}

.hero-subtitle {
    color: var(--primary-red);
    font-weight: 600;
    letter-spacing: 2px;
    text-transform: uppercase;
    margin-bottom: 16px;
    display: block;
}

.hero h1 {
    font-size: 4rem;
    margin-bottom: 24px;
}

.hero p {
    font-size: 1.25rem;
    color: var(--text-gray);
    margin-bottom: 40px;
}

.bg-pattern {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: -1;
    opacity: 0.1;
    background-image: radial-gradient(var(--primary-blue) 1px, transparent 1px);
    background-size: 40px 40px;
}

/* Skill Cards */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.skill-card {
    background: var(--bg-white);
    padding: 40px;
    border-radius: 16px;
    border: 1px solid var(--border-color);
    transition: all var(--transition-slow);
    position: relative;
    overflow: hidden;
}

.skill-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-blue);
}

.skill-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-blue), var(--primary-red));
    transform: scaleX(0);
    transition: transform var(--transition-slow);
    transform-origin: left;
}

.skill-card:hover::before {
    transform: scaleX(1);
}

.skill-card i {
    font-size: 2.5rem;
    color: var(--primary-blue);
    margin-bottom: 24px;
    display: block;
    transition: transform var(--transition-slow);
}

.skill-card:hover i {
    transform: scale(1.1) rotate(5deg);
    color: var(--primary-red);
}

.skill-card h3 {
    font-size: 1.5rem;
    margin-bottom: 12px;
}

/* Footer */
footer {
    background: var(--light-gray);
    padding: 60px 0 30px;
    border-top: 1px solid var(--border-color);
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr;
    gap: 60px;
    margin-bottom: 40px;
}

.footer-logo {
    margin-bottom: 20px;
}

.footer-links h4 {
    margin-bottom: 24px;
    font-size: 1.1rem;
}

.footer-links ul li {
    margin-bottom: 12px;
}

.footer-bottom {
    padding-top: 30px;
    border-top: 1px solid var(--border-color);
    text-align: center;
    color: var(--text-gray);
    font-size: 0.9rem;
}

/* Mobile Responsive */
@media (max-width: 768px) {
    .hero h1 {
        font-size: 3rem;
    }
    .nav-links {
        display: none;
    }
    .mobile-menu-btn {
        display: block;
    }
    .footer-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
}