#header {
    display: flex;
    flex-direction: column;
    width: 80%;
    max-width: 800px;
    margin: 0px auto;
    padding: 20px 40px;
    border: 1px solid rgba(0, 0, 0, 0.2);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    background-color: rgb(253, 253, 255);
}

#header h1 {
    margin: 0px;
    margin-bottom: 20px;
    display: flex;
}

/* navigator */
.nav {
    margin-left: auto;
}

.nav ul {
    list-style: none;
}

.nav ul li {
    margin: 5px;
}

.nav span {
    margin-right: 10px;
}

.nav ul li a {
    color: #555;
    text-decoration: none;
    font-size: 13px;
    margin: 3px;
    padding: 5px;
    border: 1px solid rgba(0, 0, 0, 0.3);
    border-radius: 8px;
    text-align: center;
    transition: background 0.4s ease;
}

.nav a:hover {
    background-color: beige;
}

/* container */
#container {
    width: 80%;
    max-width: 800px;
    margin: 30px auto;
    padding: 40px;
    border: 1px solid rgba(0, 0, 0, 0.2);
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    background-color: rgb(253, 253, 255);
}

.container-title {
    font-size: 30px;
    margin: 0 0 30px 0;
}

/* intro */
.intro {
    display: flex;
    align-items: center;
    margin-bottom: 20px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.3);
    padding-bottom: 20px;
}

.intro-photo {
    width: 110px;
    height: 120px;
    border-radius: 50%;
    margin-right: 50px;
}

.intro-info h1 {
    font-size: 24px;
    margin: 0;
}

.intro-info p {
    font-size: 16px;
    color: #555;
}

.intro-info h5 {
    margin: 5px 0;
    color: grey;
}

.intro-info a {
    margin: 5px 0;
    color: brown;
    font-size: 13px;
    font-weight: bold;
    text-decoration: none;
}

/* innerdiv */
.innerdiv {
    margin-bottom: 20px;
    border-bottom: 1px solid rgba(0, 0, 0, 0.3);
}

.innerdiv-edu-exper {
    margin: 0 0 35px 0;
    border-left: 2px solid grey;
    padding-left: 20px;
}

.innerdiv-edu-exper h3 {
    margin: 5px 0;
}

.innerdiv-edu-exper h5 {
    margin: 5px 0;
    color: dimgray;
}

.innerdiv-projects {
    margin: 0 0 35px 0;
    border-left: 2px solid rgba(185, 105, 105, 0.4);
    padding-left: 20px;
}

.innerdiv-projects h5,
.innerdiv-projects a {
    margin: 5px 0;
    color: dimgray;
}

.innerdiv-projects img {
    display: inline-block;
    width: 95%;
}

/* social links */
.social-links {
    display: flex;
    justify-content: center;
    margin-top: 20px;
}

.social-links a {
    display: inline-block;
    width: 40px;
    height: 40px;
}

.social-links img {
    width: 100%;
    height: 100%;
}

/* Skill */
.skills {
    margin-bottom: 15px;
    text-align: left;
    width: 90%;
    margin: 15px auto;
}

.skills-progress {
    background-color: #e0e0e0;
    border-radius: 5px;
    height: 10px;
    width: 100%;
}

.skills-progress-bar {
    height: 10px;
    border-radius: 5px;
}

/* Contact */
.form-head {
    margin-bottom: 10px;
    display: flex;
}

.form-head-label,
.form-body-label {
    margin-right: 10px;
    font-weight: bold;
    font-size: 20px;
}

.form-head-input {
    width: 100%;
    padding: 5px;
    font-size: 18px;
}

.form-body-input {
    width: 100%;
    height: 150px;
    font-size: 16px;
    padding: 6px;
    font-family: Arial, Helvetica, sans-serif;
    resize: none;
}

.contact-button {
    border: none;
}

/* footer */
#footer {
    background-color: grey;
    color: white;
    text-align: center;
    padding: 10px 0;
}

#footer p {
    margin: 5px;
}

/* media */
@media (max-width: 768px) {
    .nav ul li {
        margin: 3px;
    }

    .nav span {
        margin-right: 5px;
    }

    .nav ul li a {
        color: #555;
        text-decoration: none;
        font-size: 9px;
        margin: 2px;
        padding: 4px;
        border: 1px solid rgba(0, 0, 0, 0.3);
        border-radius: 8px;
        text-align: center;
        transition: background 0.4s ease;
    }

    .nav a:hover {
        background-color: beige;
    }

    .form-head {
        margin-bottom: 5px;
        display: flex;
    }

    .form-head-label,
    .form-body-label {
        margin-right: 5px;
        font-weight: bold;
        font-size: 15px;
    }

    .form-head-input {
        width: 100%;
        font-size: 14px;
    }

    .form-body-input {
        width: 100%;
        height: 150px;
        padding: 5px;
        font-size: 14px;
        font-family: Arial, Helvetica, sans-serif;
        resize: none;
    }
}

@media (max-width: 480px) {
    .intro-info p {
        font-size: 12px;
    }

    .nav ul li {
        margin: 3px;
    }

    .nav span {
        margin-right: 4px;
    }

    .nav ul li a {
        color: #555;
        text-decoration: none;
        font-size: 7px;
        margin: 2px;
        padding: 3px;
        border: 1px solid rgba(0, 0, 0, 0.3);
        border-radius: 8px;
        text-align: center;
        transition: background 0.4s ease;
    }

    .nav a:hover {
        background-color: beige;
    }

    .form-head {
        margin-bottom: 2px;
        display: inline;
    }

    .form-head-label,
    .form-body-label {
        margin-right: 1px;
        font-weight: bold;
        font-size: 11px;
    }

    .form-head-input {
        width: 100%;
        font-size: 13px;
    }

    .form-body-input {
        width: 100%;
        height: 150px;
        padding: 3px;
        font-size: 11px;
        font-family: Arial, Helvetica, sans-serif;
        resize: none;
    }
}

/* light theme */
body {
    background-color: white;
    color: black;
    font-family: sans-serif;
    transition: background-color 0.3s ease, color 0.3s ease;
}

#light-dark {
    font-size: 20px;
    margin-right: 10px;
    padding: 8px 12px;
    cursor: pointer;
    background: none;
    border: 1px solid #aaa;
    border-radius: 8px;
    margin-left: auto;
    display: flex;
}

/* dark theme */
body.dark {
    background-color: #121212;
    color: #f1f1f1;
}

body.dark #light-dark {
    border-color: #eee;
    color: white;
}

body.dark #header,
body.dark #container,
body.dark .innerdiv,
body.dark .intro,
body.dark .repo-card {
    background-color: #1e1e1e;
    color: #f1f1f1;
    border-color: rgba(255, 255, 255, 0.2);
}

body.dark h5,
body.dark a,
body.dark .intro-info h5,
body.dark .innerdiv-edu-exper h5 {
    color: #ccc;
}

body.dark .intro-info p {
    color: #ddd;
}

body.dark .nav ul li a,
body.dark .filter-btn {
    background-color: #2a2a2a;
    color: white;
    border-color: rgba(255, 255, 255, 0.3);
}

body.dark .nav a:hover {
    background-color: #3a3a3a;
}

#project-filter {
    margin: 20px 0;
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.filter-btn {
    padding: 8px 14px;
    font-size: 14px;
    cursor: pointer;
    border: 1px solid rgba(0, 0, 0, 0.3);
    border-radius: 8px;
    background-color: white;
}

.filter-btn.active {
    background-color: grey;
    color: white;
    font-weight: bold;
}

body.dark .filter-btn {
    background-color: #2c2c2c;
    color: #ddd;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

body.dark .filter-btn.active {
    background-color: #3b82f6;
    color: #fff;
    font-weight: bold;
}

/* Repository Card */
.repo-card {
    border: 1px solid rgba(0, 0, 0, 0.1);
    padding: 0 15px 15px;
    margin: 10px;
    border-radius: 20px;
    background-color: rgb(249, 249, 249);
}

.repo-card h3 a {
    text-decoration: none;
}

.repo-card:hover {
    transform: translateY(-4px);
    box-shadow: 0 0 5px;
}

.repo-card span {
    font-weight: 500;
    font-size: 12px;
}

body.dark .repo-card {
    background-color: rgba(255, 255, 255, 0.1);
}

body.dark .repo-card:hover {
    box-shadow: 0 0 5px rgba(125, 255, 255);
}

body.dark .repo-card h3 a {
    color: #ccc;
}