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

body {
    font-family: 'Arial', sans-serif;
    line-height: 1.6;
    color: #333;
    background: linear-gradient(to bottom, #fff8f8, #fff);
}


header {
    background: linear-gradient(rgba(139, 0, 0, 0.85), rgba(178, 34, 34, 0.9)), 
                url('img/con-ngua.jpg') no-repeat center center;
    background-size: cover;
    min-height: 50vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 1.5rem;
}

.header-overlay {
    max-width: 95%;
    padding: 1.5rem;
}

.header-overlay h1 {
    font-size: 2.2rem;
    color: #FFD700;
    margin-bottom: 0.8rem;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.5);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    padding: 0 1rem;
}

.header-overlay p {
    font-size: 1.2rem;
    color: white;
    font-style: italic;
}


nav {
    background: #8b0000;
    padding: 0;
    display: flex;
    flex-wrap: nowrap;
    justify-content: center;
    align-items: stretch;
    gap: 0;
    position: sticky;
    top: 0;
    z-index: 100;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
    min-height: 50px;
}

nav a, .dropdown label {
    color: white;
    text-decoration: none;
    padding: 0;
    font-weight: 500;
    transition: all 0.2s;
    white-space: nowrap;
    flex-shrink: 0;
    height: 50px;
    display: flex;
    align-items: center;
    justify-content: center;
    border: none;
    background: transparent;
}

nav > a {
    padding: 0 20px;
    border-right: 1px solid rgba(255, 255, 255, 0.2);
}

nav > a:first-child {
    border-left: 1px solid rgba(255, 255, 255, 0.2);
}

nav a:hover, .dropdown:hover label {
    background: #FFD700;
    color: #8b0000;
}


.dropdown {
    position: relative;
    display: flex;
    align-items: center;
    height: 50px;
}

.dropdown label {
    padding: 0 20px;
    cursor: pointer;
    margin: 0;
    border-right: 1px solid rgba(255, 255, 255, 0.2);
    width: 100%;
    height: 100%;
}

.dropdown-content {
    display: none;
    position: absolute;
    background: white;
    min-width: 200px;
    box-shadow: 0 3px 10px rgba(0,0,0,0.15);
    border-radius: 0 0 4px 4px;
    top: 100%;
    left: 0;
    border: 1px solid #ddd;
    border-top: none;
    z-index: 1000;
}

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

.dropdown-content a {
    color: #333;
    display: block;
    padding: 12px 16px;
    border-bottom: 1px solid #eee;
    text-decoration: none;
    transition: all 0.2s;
    white-space: nowrap;
    height: auto;
    justify-content: flex-start;
}

.dropdown-content a:last-child {
    border-bottom: none;
}

.dropdown-content a:hover {
    background: #8b0000;
    color: white;
}


.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 2rem;
}

section {
    background: white;
    margin: 1.5rem 0;
    padding: 2rem;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.05);
    border-left: 4px solid #8b0000;
}

.title-red {
    color: #8b0000;
    font-size: 1.8rem;
    margin-bottom: 1.5rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid #FFD700;
}


.custom-item {
    margin: 2rem 0;
}

.custom-item img {
    width: 100%;
    max-width: 700px;
    height: auto;
    border-radius: 6px;
    display: block;
    margin: 1rem auto;
    border: 1px solid #ddd;
}

.custom-item p.caption,
.custom-item p[style*="text-align: center"] {
    text-align: center;
    color: #666;
    font-style: italic;
    font-size: 0.9rem;
    margin-top: 0.5rem;
}


.videos {
    width: 100%;
    max-width: 800px;
    height: auto;
    aspect-ratio: 16/9;
    border-radius: 6px;
    display: block;
    margin: 1rem auto;
    border: 2px solid #8b0000;
}


.media-box {
    background: #fff9e6;
    padding: 1.5rem;
    border-radius: 6px;
    margin: 1.5rem 0;
    border: 1px solid #FFD700;
}

.modern-box {
    background: #f0fff0;
    padding: 1.5rem;
    border-radius: 6px;
    margin: 1.5rem 0;
    border: 1px solid #8b0000;
}


.form-style {
    background: #fff;
    padding: 2rem;
    border-radius: 8px;
    border: 2px solid #8b0000;
}

.form-style label {
    display: block;
    margin: 1rem 0 0.5rem;
    color: #8b0000;
    font-weight: 500;
}

.form-style input,
.form-style select,
.form-style textarea {
    width: 100%;
    padding: 0.8rem;
    border: 1px solid #ccc;
    border-radius: 4px;
    margin-bottom: 1rem;
}

.form-style button {
    background: #8b0000;
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: 4px;
    cursor: pointer;
    font-size: 1rem;
    width: 100%;
    max-width: 200px;
    display: block;
    margin: 1rem auto;
}

.form-style button:hover {
    background: #b22222;
}


footer {
    background: #333;
    color: white;
    text-align: center;
    padding: 2rem 1rem;
    margin-top: 3rem;
}

footer p {
    margin: 0.5rem 0;
}

footer a {
    color: #FFD700;
    text-decoration: none;
    display: inline-block;
    margin: 1rem 0;
    padding: 0.5rem 1rem;
    border: 1px solid #FFD700;
    border-radius: 4px;
}

footer a:hover {
    background: #FFD700;
    color: #333;
}


@media (max-width: 768px) {
    /* Header responsive */
    .header-overlay h1 {
        font-size: 1.6rem;
        white-space: normal;
        line-height: 1.3;
    }
    
    .header-overlay p {
        font-size: 1rem;
    }
    
    /* Nav responsive */
    nav {
        flex-wrap: wrap;
        min-height: auto;
    }
    
    nav > a, .dropdown label {
        height: 45px;
        padding: 0 15px;
        font-size: 0.9rem;
        flex: 1;
        min-width: 120px;
        text-align: center;
    }
    
    .dropdown-content {
        position: fixed;
        top: auto;
        left: 50%;
        transform: translateX(-50%);
        width: 90%;
        max-width: 300px;
        border-radius: 4px;
        border-top: 1px solid #ddd;
    }
    
    /* Container giữ nguyên */
    .container {
        padding: 1rem;
    }
    
    section {
        padding: 1.5rem;
    }
}

@media (max-width: 480px) {
    .header-overlay h1 {
        font-size: 1.4rem;
    }
    
    nav {
        flex-direction: column;
        align-items: stretch;
    }
    
    nav a, .dropdown label {
        text-align: center;
        margin: 0.2rem 0;
        border: none !important;
    }
}


audio {
    width: 100%;
    max-width: 300px;
    margin: 1rem 0;
}