/* Thiết lập cơ bản (Reset và Font) */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    line-height: 1.6;
    color: #333;
    background-color: #f4f4f4;
}

.container {
    width: 80%;
    max-width: 1100px;
    margin: auto;
    overflow: hidden;
    padding: 20px 0;
}

/* HEADER (Navigation Bar) */
header {
    background: #333;
    color: #fff;
    padding-top: 10px;
    min-height: 70px;
    border-bottom: #0779e4 3px solid;
    position: sticky;
    top: 0;
    z-index: 1000;
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

header h1 {
    font-size: 24px;
}

header a {
    color: #fff;
    text-decoration: none;
    text-transform: uppercase;
    font-size: 16px;
    margin-left: 15px;
    transition: color 0.3s;
}

header a:hover {
    color: #0779e4;
}

/* HERO SECTION (Giới thiệu) */
.hero {
    text-align: center;
    padding: 80px 0;
    background: #fff;
}

.profile-pic {
    width: 150px;
    height: 150px;
    border-radius: 50%; /* Làm cho ảnh tròn */
    object-fit: cover;
    margin-bottom: 20px;
    border: 5px solid #ddd;
}

.hero h2 {
    color: #333;
    margin-bottom: 10px;
}

.hero .tagline {
    font-size: 1.2em;
    color: #555;
    margin-bottom: 30px;
}

.btn {
    display: inline-block;
    background: #0779e4;
    color: #fff;
    padding: 10px 20px;
    text-decoration: none;
    border-radius: 5px;
    transition: background 0.3s;
}

.btn:hover {
    background: #055ba9;
}

/* SECTION CHUNG */
section {
    padding: 40px 0;
    border-bottom: 1px solid #ddd;
}

section h3 {
    text-align: center;
    font-size: 2em;
    margin-bottom: 30px;
    color: #0779e4;
}

/* ABOUT ME (Về tôi) */
.about {
    background: #f9f9f9;
    text-align: justify;
}

.about p {
    margin-bottom: 15px;
}

/* PROJECTS (Dự án) */
.projects {
    background: #fff;
}

.project-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.project-item {
    background: #f4f4f4;
    padding: 20px;
    border-radius: 5px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
}

.project-item h4 {
    color: #333;
    margin-bottom: 10px;
}

.project-link {
    display: inline-block;
    margin-top: 10px;
    margin-right: 10px;
    color: #0779e4;
    text-decoration: none;
    font-weight: bold;
}

.project-link:hover {
    text-decoration: underline;
}

/* CONTACT (Liên hệ) */
.contact {
    text-align: center;
    background: #f9f9f9;
}

.contact ul {
    list-style: none;
    padding: 0;
    margin-top: 20px;
}

.contact li {
    margin-bottom: 10px;
}

.contact a {
    color: #0779e4;
    text-decoration: none;
}

.contact a:hover {
    text-decoration: underline;
}

/* FOOTER */
footer {
    background: #333;
    color: #fff;
    text-align: center;
    padding: 15px 0;
    font-size: 0.9em;
}

/* RESPONSIVE (Dành cho điện thoại di động) */
@media (max-width: 768px) {
    header .container {
        flex-direction: column;
        text-align: center;
    }

    header nav {
        padding-top: 10px;
    }

    header a {
        display: block;
        margin: 5px 0;
    }

    .project-list {
        grid-template-columns: 1fr; /* Chỉ 1 cột trên điện thoại */
    }
}