:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --accent: #3b82f6;
    --accent-hover: #2563eb;
    --card-bg: #ffffff;
    --border: #e2e8f0;
    --shadow: 0 10px 25px -5px rgba(0,0,0,0.05), 0 8px 10px -6px rgba(0,0,0,0.02);
    --transition: 0.2s ease;
    --bg-primary-rgb: 255, 255, 255;
}

body.dark-mode {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #cbd5e1;
    --card-bg: #1e293b;
    --border: #334155;
    --shadow: 0 10px 25px -5px rgba(0,0,0,0.3);
    --bg-primary-rgb: 15, 23, 42;
}

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

body {
    font-family: 'Inter', sans-serif;
    background: var(--bg-primary);
    color: var(--text-primary);
    line-height: 1.5;
    transition: background-color 0.3s ease, color 0.3s ease;
}


body.light-mode {
    --bg-primary: #ffffff;
    --bg-secondary: #f8fafc;
    --text-primary: #0f172a;
    --text-secondary: #334155;
    --card-bg: #ffffff;
    --border: #e2e8f0;
    --bg-primary-rgb: 255, 255, 255;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* header */
.header {
    position: sticky;
    top: 0;
    background: var(--bg-primary);
    border-bottom: 1px solid var(--border);
    backdrop-filter: blur(8px);
    background-color: rgba(var(--bg-primary-rgb), 0.95);
    z-index: 100;
    padding: 1rem 0;
}
.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}
.logo {
    font-weight: 700;
    font-size: 1.5rem;
    color: var(--accent);
    text-decoration: none;
}
.nav-links {
    display: flex;
    gap: 1.8rem;
}
.nav-links a {
    text-decoration: none;
    color: var(--text-secondary);
    font-weight: 500;
    transition: color 0.2s;
}
.nav-links a:hover {
    color: var(--accent);
}
.header-controls {
    display: flex;
    gap: 0.8rem;
    align-items: center;
}
.icon-btn {
    background: transparent;
    border: 1px solid var(--border);
    border-radius: 2rem;
    padding: 0.4rem 0.9rem;
    cursor: pointer;
    color: var(--text-primary);
    font-size: 0.9rem;
    transition: 0.2s;
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
}
.icon-btn:hover {
    background: var(--accent);
    color: white;
    border-color: var(--accent);
}
.github-header {
    text-decoration: none;
}
.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    color: var(--text-primary);
    cursor: pointer;
}
.mobile-nav {
    display: none;
}
.section {
    padding: 5rem 0;
}
.alt-bg {
    background: var(--bg-secondary);
}
.section-title {
    font-size: 2rem;
    font-weight: 700;
    margin-bottom: 2rem;
    position: relative;
    display: inline-block;
}
.hero-grid {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 2rem;
    flex-wrap: wrap;
}
.hero-content {
    flex: 1;
}
.hero-badge {
    font-size: 0.9rem;
    background: var(--accent);
    color: white;
    padding: 0.2rem 1rem;
    border-radius: 2rem;
    display: inline-block;
    margin-bottom: 1rem;
}
.hero-title {
    font-size: 3rem;
    font-weight: 800;
    margin-bottom: 0.5rem;
}
.hero-subtitle {
    font-size: 1.2rem;
    color: var(--accent);
    margin-bottom: 1rem;
}
.hero-desc {
    color: var(--text-secondary);
    margin-bottom: 2rem;
    max-width: 500px;
}
.btn {
    padding: 0.7rem 1.5rem;
    border-radius: 2rem;
    text-decoration: none;
    font-weight: 600;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    transition: 0.2s;
    cursor: pointer;
    border: none;
    font-size: 1rem;
    font-family: inherit;
}
.btn-primary {
    background: var(--accent);
    color: white;
}
.btn-primary:hover {
    background: var(--accent-hover);
    transform: translateY(-2px);
}
.btn-outline {
    border: 1px solid var(--border);
    background: transparent;
    color: var(--text-primary);
}
.hero-avatar .avatar-circle {
    width: 220px;
    height: 220px;
    background: linear-gradient(135deg, var(--accent), #8b5cf6);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 5rem;
    color: white;
    box-shadow: var(--shadow);
}
.about-card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 1.5rem;
    box-shadow: var(--shadow);
    border: 1px solid var(--border);
}
.about-detail {
    margin-top: 1rem;
    color: var(--text-secondary);
}
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
}
.skill-card {
    background: var(--card-bg);
    padding: 1.2rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
    font-weight: 600;
}
.skill-card i {
    margin-right: 0.5rem;
    color: var(--accent);
}
.skill-bar {
    margin-top: 0.5rem;
    background: var(--border);
    border-radius: 1rem;
    overflow: hidden;
}
.skill-bar div {
    background: var(--accent);
    height: 8px;
    width: 0%;
    border-radius: 1rem;
    transition: width 0.3s;
}
.edu-list {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}
.edu-item {
    display: flex;
    gap: 1rem;
    align-items: center;
    background: var(--card-bg);
    padding: 1.2rem;
    border-radius: 1rem;
    border: 1px solid var(--border);
}
.edu-item i {
    font-size: 2rem;
    color: var(--accent);
}
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}
.project-card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 1.2rem;
    border: 1px solid var(--border);
    transition: transform 0.2s;
}
.project-card:hover {
    transform: translateY(-5px);
}
.project-card i {
    font-size: 2.2rem;
    color: var(--accent);
    margin-bottom: 0.5rem;
}
.project-link {
    color: var(--accent);
    text-decoration: none;
    font-weight: 500;
    display: inline-block;
    margin-top: 1rem;
}
.contact-wrapper {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
}
.contact-form .form-group {
    margin-bottom: 1.2rem;
}
.contact-form label {
    display: block;
    margin-bottom: 0.3rem;
    font-weight: 500;
}
.contact-form input, 
.contact-form textarea {
    width: 100%;
    padding: 0.7rem;
    border-radius: 0.8rem;
    border: 1px solid var(--border);
    background: var(--bg-primary);
    color: var(--text-primary);
    font-family: inherit;
    transition: border 0.2s;
}
.contact-form input:focus, 
.contact-form textarea:focus {
    outline: none;
    border-color: var(--accent);
}
.error-msg {
    font-size: 0.8rem;
    color: #ef4444;
    display: block;
    margin-top: 0.2rem;
}
.form-status {
    margin-top: 1rem;
}
.contact-info {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 1.2rem;
    border: 1px solid var(--border);
}
.contact-info p {
    margin: 1rem 0;
}
.contact-info i {
    margin-right: 0.5rem;
    color: var(--accent);
}
.footer {
    border-top: 1px solid var(--border);
    padding: 2rem 0;
    text-align: center;
}
.footer-links a {
    color: var(--text-secondary);
    text-decoration: none;
    margin-top: 0.5rem;
    display: inline-block;
}

@media (max-width: 480px) 
.nav-links {
    display: none;
}
.header-controls {
    .mobile-menu-btn {
        display: block;
    }
    .mobile-nav {
        display: flex;
        flex-direction: column;
        background: var(--bg-primary);
        padding: 1rem;
        gap: 0.5rem;
        border-bottom: 1px solid var(--border);
        position: fixed;
        top: 70px;
        left: 0;
        right: 0;
        z-index: 99;
        transform: translateX(100%);
        transition: transform 0.3s ease;
    }
    .mobile-nav.open {
        transform: translateX(0);
    }
    .mobile-nav a {
        text-decoration: none;
        color: var(--text-primary);
        padding: 0.5rem;
    }
    .hero-grid {
        flex-direction: column-reverse;
        text-align: center;
    }
    .hero-title {
        font-size: 2.2rem;
    }
    .hero-desc {
        margin-left: auto;
        margin-right: auto;
    }
    .hero-buttons {
        justify-content: center;
    }
    .contact-wrapper {
        grid-template-columns: 1fr;
    }
    .section {
        padding: 3rem 0;
    }
    .section-title {
        font-size: 1.75rem;
    }
}

@media print {
    .header, 
    .footer, 
    .hero-buttons, 
    .icon-btn, 
    .mobile-menu-btn, 
    .header-controls, 
    .contact-form, 
    .contact-info,
    .nav-links {
        display: none !important;
    }
    body {
        margin: 0;
        padding: 1cm;
        background: white;
        color: black;
    }
    .section {
        break-inside: avoid;
        padding: 1rem 0;
    }
    .hero-avatar {
        display: none;
    }
    .hero-grid {
        flex-direction: column;
    }
}