html {
    --main-color: #4a90e2;
    --bg-color: #f5f7fa;
    --text-color: #1a1a1a;
    --card-bg: #fff;
    --card-shadow: rgba(0, 0, 0, 0.1);
}

body {
    margin: 0;
    font-family: 'Segoe UI', sans-serif;
    background: var(--bg-color);
    color: var(--text-color);
    transition: background 0.3s, color 0.3s;
}

.toggle-dark {
    position: fixed;
    top: 0.5rem;
    right: 1rem;
    background-color: var(--main-color);
    color: #fff;
    border: none;
    padding: 0.6rem 1rem;
    border-radius: 30px;
    font-size: 1.2rem;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.1);
    z-index: 2000;
}

header {
    text-align: center;
    background: var(--main-color);
    color: white;
    padding: 3rem 1rem;
    border-bottom-left-radius: 30px;
    border-bottom-right-radius: 30px;
}

.avatar-wrapper {
    display: flex;
    justify-content: center;
    margin-bottom: 1rem;
}

.avatar {
    width: 140px;
    height: 140px;
    border-radius: 50%;
    border: 5px solid white;
    object-fit: cover;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.2);
}

nav {
    position: sticky;
    top: 0;
    background-color: var(--bg-color);
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1rem;
    padding: 1rem;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

nav a {
    text-decoration: none;
    color: var(--main-color);
    font-weight: 600;
    transition: 0.2s;
    position: relative;
}

nav a:hover {
    color: #003e9f;
}

main {
    max-width: 800px;
    margin: 2rem auto;
    padding: 0 1rem;
    background: var(--bg-color);
}

main #about p {
    text-align: center;
}

.card {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: 20px;
    box-shadow: 0 8px 16px var(--card-shadow);
    margin-bottom: 2rem;

    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

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

.skills span {
    display: inline-block;
    background-color: var(--main-color);
    color: white;
    padding: 0.4rem 0.8rem;
    margin: 0.3rem;
    border-radius: 20px;
    font-size: 0.9rem;
}

footer {
    background-color: var(--main-color);
    color: white;
    text-align: center;
    padding: 2rem;
    border-top-left-radius: 30px;
    border-top-right-radius: 30px;
}

.btn-export {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background-color: var(--main-color);
    color: white;
    border: none;
    padding: 0.8rem 1.2rem;
    border-radius: 10px;
    font-size: 1rem;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    transition: background-color 0.3s;
}

.btn-export:hover {
    background-color: #005f8a;
}

body.dark {
    --bg-color: #0d1117;
    --text-color: #c9d1d9;
    --main-color: #58a6ff;
    --card-bg: #161b22;
    --card-shadow: rgba(0, 0, 0, 0.6);
}

body.dark nav {
    background-color: #161b22;
    box-shadow: 0 2px 5px rgba(255, 255, 255, 0.1);
}

body.dark nav a {
    color: #58a6ff;
}

body.dark nav a:hover {
    color: #1f6feb;
}

body.dark .toggle-dark {
    background-color: #21262d;
    color: #58a6ff;
}

body.dark footer {
    background-color: #161b22;
    color: #8b949e;
}

body.dark .skills span {
    background-color: #21262d;
    color: #58a6ff;
}

@media (max-width: 768px) {
    nav {
        flex-direction: column;
        gap: 0.5rem;
        padding: 1rem 0.5rem;
    }

    .avatar {
        width: 100px;
        height: 100px;
    }

    .card {
        padding: 1rem;
    }

    header {
        padding: 2rem 1rem;
    }

    .toggle-dark {
        font-size: 1rem;
        padding: 0.5rem 0.8rem;
    }

    .btn-export {
        padding: 0.6rem 1rem;
        font-size: 0.9rem;
    }

    .skills span {
        font-size: 0.8rem;
        padding: 0.3rem 0.6rem;
    }
}

@media (max-width: 480px) {
    nav {
        flex-direction: column;
        align-items: center;
        gap: 0.3rem;
    }

    header {
        padding: 1.5rem 0.5rem;
    }

    .avatar {
        width: 80px;
        height: 80px;
    }

    main {
        padding: 0 0.5rem;
    }

    .card {
        padding: 0.8rem;
    }

    .toggle-dark {
        top: 0.3rem;
        right: 0.5rem;
    }

    .btn-export {
        bottom: 15px;
        right: 15px;
    }
}

@media print {
    body {
        background: white !important;
        color: black !important;
    }

    nav,
    .toggle-dark,
    .btn-export {
        display: none !important;
    }

    header,
    footer {
        page-break-before: avoid;
        page-break-after: avoid;
    }

    .card {
        box-shadow: none !important;
        page-break-inside: avoid;
        break-inside: avoid;
    }

    .skills span {
        background-color: #333 !important;
        color: white !important;
    }

    a {
        color: black !important;
        text-decoration: none;
    }
}