/* Thiết lập cơ bản */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: #fff;
    font-size: 16px;
    line-height: 1.5;
    color: #333;
}

.container {
    width: 100%;
    margin: 0 auto;
    padding: 0 15px;
}
.container-index {
    width: 100%;
    margin: 0 auto;
    padding: 0 15px;
    max-width: 1200px;
}

img {
    max-width: 100%;
    height: auto;
}

/* Header và Navigation */
header {
    background-color: white;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.header-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px 0;
    width: 95%;
    margin: 0 auto;
}

.logo img {
    height: 50px;
}

.mobile-menu-toggle {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: #007bff;
}

.main-nav ul {
    display: flex;
    list-style: none;
    flex-wrap: wrap;
    justify-content: center;
    padding-left: 50px;
    padding-right: 50px;
}

.main-nav li {
    margin: 0 10px;
}

.main-nav a {
    color: #333;
    padding: 3px;
    display: block;
    transition: color 0.3s;
    font-weight: 600;
    font-family: "Open Sans", sans-serif;
    font-size: 15px;
    text-decoration: none;
    color: #444;
}

.main-nav a:hover {
    color: #007bff;
}

.user-profile {
    margin-left: 15px;
}

.circle-icon {
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background-color: #2196F3;
    display: block;
}

/* Hero Section */
.hero {
    background-image: url('grid-bg.png');
    background-size: cover;
    padding: 40px 0;
    background-color: #e9f5ff;
}

.hero-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
}

.hero-text {
    text-align: center;
    flex: 1;
    padding: 0 20px;
    min-width: 250px;
}

.hero-text h1 {
    color: #2196F3;
    font-size: 2rem;
    margin-bottom: 15px;
}

.hero-text p {
    font-size: 1rem;
    line-height: 1.6;
}

.education-icons {
    display: flex;
    flex-direction: column;
    align-items: center;
    margin: 0 10px;
}

.edu-icon {
    width: 60px;
    margin: 10px;
    transition: transform 0.3s;
}

.edu-icon:hover {
    transform: scale(1.1);
}

/* Curriculum Section */
.curriculum {
    padding: 40px 0;
    background: #fff;
}

.curriculum h2 {
    color: #003366;
    font-size: 1.5rem;
    margin-bottom: 30px;
    text-align: left;
    font-family: "Open Sans", sans-serif;
    font-weight: 600;
    text-decoration: none;
}

.class-selectors {
    display: flex;
    flex-direction: column;
    gap: 15px;
}

.class-dropdown {
    position: relative;
    width: 100%;
}

.dropdown-btn {
    width: 100%;
    padding: 15px;
    background-color: #f8fafc;
    border: 1px solid #ddd;
    border-radius: 5px;
    font-size: 1.2rem;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background-color 0.3s;
    text-align: left;
    font-family: "Open Sans", sans-serif;
    font-weight: 700;
    text-decoration: none;
}

.dropdown-btn:hover {
    background-color: #f9f9f9;
}

.class-dropdown.active .dropdown-btn {
    border-bottom-left-radius: 0;
    border-bottom-right-radius: 0;
    border-bottom: none;
}

.dropdown-content {
    display: none;
    background-color: white;
    border: 1px solid #ddd;
    border-top: none;
    border-bottom-left-radius: 5px;
    border-bottom-right-radius: 5px;
}

.dropdown-content.show {
    display: block;
}

.program-options {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 15px;
    width: 100%;
    padding-top: 15px;
    padding-right: 20px;
    padding-bottom: 20px;
    padding-left: 20px;
}

@media screen and (max-width: 1200px) {
    .program-options {
        grid-template-columns: repeat(3, 1fr);
    }
}

@media screen and (max-width: 900px) {
    .program-options {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media screen and (max-width: 600px) {
    .program-options {
        grid-template-columns: 1fr;
    }
}

.program-option {
    padding: 15px;
    background-color: transparent;
    transition: none;
}

.program-option:hover {
    box-shadow: none;
    transform: none;
}

.program-title {
    font-weight: bold;
    color: green;
    font-size: 1.4rem;
    margin-bottom: 30px;
    display: block;
    font-family: "Open Sans", sans-serif;
}

.program-description {
    color: #333;
    font-size: 1rem;
    margin-top: 5px;
    line-height: 1.8;
}

.program-description p {
    margin-bottom: 10px;
    font-weight: 500;
    font-size: 1rem;
    color: #333;
    font-family: "Open Sans", sans-serif;
}

.program-description p a {
    text-decoration: none !important;
    margin-bottom: 10px;
    font-weight: 500;
    font-size: 1rem;
    color: #333;
    font-family: "Open Sans", sans-serif;
}

.program-description p a:hover {
    color: #003366;
    /* Màu đậm hơn khi hover */
}

.program-description strong {
    color: #005794;
    font-size: 16px;
    font-weight: 700;
    font-family: 'Open Sans', sans-serif;
}

.program-description em {
    font-style: italic;
}

.program-description u {
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 992px) {
    .hero-content {
        flex-direction: column;
    }

    .education-icons {
        flex-direction: row;
        margin: 20px 0;
    }

    .hero-text {
        order: -1;
        margin-bottom: 20px;
    }

    .program-options {
        flex-direction: column;
    }
}

@media (max-width: 992px) {
    .mobile-menu-toggle {
        display: block;
    }

    .main-nav {
        position: absolute;
        top: 100%;
        left: 0;
        width: 100%;
        background-color: white;
        display: none;
        padding: 10px;
        box-shadow: 0 5px 10px rgba(0, 0, 0, 0.1);
    }

    .main-nav.show {
        display: block;
    }

    .main-nav ul {
        flex-direction: column;
        padding-left: 0px;
    }

    .main-nav li {
        margin: 0;
        border-bottom: 1px solid #eee;
    }

    .main-nav a {
        padding: 10px 15px;
    }

    .hero-text h1 {
        font-size: 1.5rem;
    }

    .hero-text p {
        font-size: 0.9rem;
    }

    .edu-icon {
        width: 40px;
    }
}

@media (max-width: 576px) {
    .hero {
        padding: 20px 0;
    }

    .curriculum {
        padding: 20px 0;
    }

    .curriculum h2 {
        font-size: 1.2rem;
    }

    .dropdown-btn {
        padding: 10px;
    }

    .program-option {
        padding: 8px;
        font-size: 0.9rem;
    }
}

.search-box {
    display: flex;
    align-items: center;
    background-color: #f5f5f5;
    border-radius: 20px;
    padding: 4px 8px;
    max-width: 250px;
    border: 1px solid #e0e0e0;
    transition: all 0.3s ease;
}

.search-box:focus-within {
    box-shadow: 0 0 5px rgba(40, 167, 69, 0.3);
    border-color: #007bff;
}

.search-box input {
    border: none;
    background: transparent;
    flex-grow: 1;
    padding: 6px 8px;
    font-size: 14px;
    color: #333;
    outline: none;
}

.search-box input::placeholder {
    color: #888;
}

.search-box button {
    background: none;
    border: none;
    color: #007bff;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 6px;
    transition: color 0.2s ease;
}

.search-box button:hover {
    color: #218838;
}

@media (max-width: 960px) {
    .search-box {
        max-width: 180px;
    }
}

@media (max-width: 576px) {
    .search-box {
        max-width: 150px;
    }

    .search-box input {
        font-size: 13px;
    }
}

/* CSS for centering logo on mobile */
@media screen and (max-width: 992px) {
    .logo {
        display: block;
        text-align: center;
        position: absolute;
        left: 0;
        right: 0;
        top: 10px;
        z-index: 5;
    }

    .logo img {
        height: 30px;
        margin: 0 auto;
    }

    .header-container {
        position: relative;
        padding-top: 5px;
        padding-bottom: 5px;
    }

    .mobile-menu-toggle {
        position: relative;
        z-index: 10;
    }

    .search-box {
        position: relative;
        z-index: 10;
        margin-left: auto;
    }
}

/* CSS mới để ẩn logo trên mobile */
@media screen and (max-width: 960px) {
    .logo {
        display: none;
    }
}