:root {
    --bg-color: #1a202c;
    --text-color: #e2e8f0;
    --header-bg: #2d3748;
    --card-bg: #2d3748;
    --primary-accent: #63b3ed;
    --secondary-accent: #90cdf4;
    --border-color: #4a5568;
    --text-muted: #a0aec0;
    --btn-hover: #2c5282;
    --shadow: 0 4px 6px rgba(0,0,0,0.3);
    
    transition: background-color 0.3s, color 0.3s;
}

body.light-mode {
    --bg-color: #f7fafc;
    --text-color: #2d3748;
    --header-bg: #fff;
    --card-bg: #fff;
    --primary-accent: #2b6cb0;
    --secondary-accent: #4299e1;
    --border-color: #e2e8f0;
    --text-muted: #4a5568;
    --btn-hover: #2c5282;
    --shadow: 0 2px 5px rgba(0,0,0,0.1);
}

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

body {
    font-family: Arial, Helvetica, sans-serif;
    line-height: 1.6;
    color: var(--text-color);
    background-color: var(--bg-color);
}

a {
    text-decoration: none;
    color: inherit;
}

header {
    background: var(--header-bg);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 100;
}

.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 1rem 5%;
    max-width: 1200px;
    margin: 0 auto;
}

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

.nav-links {
    list-style: none;
    display: flex;
    gap: 2rem;
}

.nav-links a:hover {
    color: var(--primary-accent);
    transition: color 0.3s ease;
}

.nav-tools {
    display: flex;
    align-items: center;
    gap: 15px;
}

#dark-mode-toggle {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    padding: 5px 10px;
    border-radius: 4px;
    cursor: pointer;
    font-size: 0.9rem;
    transition: background 0.3s;
}

#dark-mode-toggle:hover {
    background: rgba(100, 100, 100, 0.2);
}

.menu-toggle {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.menu-toggle span {
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    transition: 0.3s;
}

.container {
    max-width: 900px;
    margin: 3rem auto;
    padding: 0 2rem;
}

#hero {
    height: 70vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    background-color: #ebf4ff22;
    padding: 0 20px;
}

body.light-mode #hero {
    background-color: #ebf4ff;
}

.hero-content h1 {
    font-size: 3rem;
    margin-bottom: 1rem;
    color: var(--text-color);
}

.hero-content p {
    font-size: 1.2rem;
    margin-bottom: 2rem;
    color: var(--text-muted);
}

.btn {
    display: inline-block;
    padding: 10px 25px;
    background-color: var(--primary-accent);
    color: #fff;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    transition: background-color 0.3s, transform 0.2s;
}

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

h2 {
    margin-bottom: 2rem;
    text-align: center;
    color: var(--text-color);
    position: relative;
}

h2::after {
    content: "";
    display: block;
    width: 60px;
    height: 3px;
    background: var(--primary-accent);
    margin: 10px auto 0;
}

.sub-section {
    margin-bottom: 2rem;
}

h3 {
    color: var(--primary-accent);
    margin-bottom: 0.5rem;
}

.item-title {
    color: var(--text-color);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--card-bg);
    box-shadow: var(--shadow);
    margin-bottom: 2rem;
}

.data-table th, .data-table td {
    padding: 15px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-color);
}

.data-table th {
    background-color: #edf2f722;
    font-weight: bold;
}

body.light-mode .data-table th {
    background-color: #edf2f7;
}

.data-table tr:hover {
    background-color: #f7fafc11;
}

body.light-mode .data-table tr:hover {
    background-color: #f7fafc;
}

.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
}

.card {
    background: var(--card-bg);
    padding: 1.5rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.card:hover {
    transform: translateY(-4px);
    box-shadow: 0 6px 10px rgba(0,0,0,0.2);
}

.card-subtitle {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 0.5rem;
}

.card-details {
    color: var(--text-muted);
    font-size: 0.95rem;
}

.skills-list {
    margin-top: 1rem;
    list-style-type: none;
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
}

.skill-tag {
    background: #edf2f722;
    color: var(--secondary-accent);
    padding: 2px 8px;
    border-radius: 4px;
    font-size: 0.8rem;
    border: 1px solid var(--border-color);
}

body.light-mode .skill-tag {
    background: #edf2f7;
    color: var(--primary-accent);
}

.contact-form {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    max-width: 550px;
    margin: 0 auto;
    box-shadow: var(--shadow);
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label, .label-text {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: bold;
    color: var(--text-muted);
}

.form-group input, .form-group select, .form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-family: inherit;
}

.form-group input:focus, .form-group select:focus, .form-group textarea:focus {
    outline: none;
    border-color: var(--primary-accent);
}

.radio-group {
    display: flex;
    align-items: center;
    gap: 10px;
    color: var(--text-muted);
}

footer {
    text-align: center;
    padding: 2rem;
    background: var(--header-bg);
    color: var(--text-muted);
    margin-top: 3rem;
    border-top: 1px solid var(--border-color);
}

@media (max-width: 768px) {
    .navbar {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .logo {
        margin-bottom: 10px;
    }

    .nav-links {
        display: none;
        flex-direction: column;
        width: 100%;
        gap: 10px;
        padding: 1rem 0;
        text-align: left;
    }

    .nav-links.active {
        display: flex;
    }

    .nav-tools {
        position: absolute;
        top: 1rem;
        right: 5%;
    }

    .menu-toggle {
        display: flex;
    }

    .hero-content h1 {
        font-size: 2.2rem;
    }
}