:root {
    --primary-red: #da251d; /* Vietnam Flag Red */
    --primary-yellow: #ffff00; /* Vietnam Flag Yellow */
    --dark-red: #b31b15;
    --gold: #ffc107;
    --text-color: #333;
    --bg-color: #f9f6f0;
    --border-color: #ddd;
}

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

body {
    font-family: 'Roboto', sans-serif;
    background-color: var(--bg-color);
    background-image: url('data:image/svg+xml,%3Csvg width="60" height="60" viewBox="0 0 60 60" xmlns="http://www.w3.org/2000/svg"%3E%3Cg fill="none" fill-rule="evenodd"%3E%3Cg fill="%23da251d" fill-opacity="0.05"%3E%3Cpath d="M36 34v-4h-2v4h-4v2h4v4h2v-4h4v-2h-4zm0-30V0h-2v4h-4v2h4v4h2V6h4V4h-4zM6 34v-4H4v4H0v2h4v4h2v-4h4v-2H6zM6 4V0H4v4H0v2h4v4h2V6h4V4H6z"/%3E%3C/g%3E%3C/g%3E%3C/svg%3E');
    color: var(--text-color);
    line-height: 1.6;
    padding: 2rem 1rem;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    min-height: 100vh;
}

.container {
    background-color: white;
    max-width: 600px;
    width: 100%;
    border-radius: 12px;
    box-shadow: 0 10px 30px rgba(0, 0, 0, 0.1);
    overflow: hidden;
    border-top: 5px solid var(--primary-red);
}

.header {
    background-color: var(--primary-red);
    color: var(--primary-yellow);
    padding: 2rem 1.5rem;
    text-align: center;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 1rem;
    position: relative;
}

.header::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 0;
    width: 100%;
    height: 10px;
    background: linear-gradient(to right, var(--primary-red), var(--primary-yellow), var(--primary-red));
}

.logo {
    width: 80px;
    height: 80px;
    background: white;
    border-radius: 50%;
    padding: 5px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.2);
    object-fit: contain;
}

.titles h1 {
    font-size: 1.2rem;
    font-weight: 700;
    text-transform: uppercase;
    margin-bottom: 0.5rem;
    letter-spacing: 0.5px;
}

.titles h2 {
    font-size: 1.8rem;
    font-weight: 700;
    text-transform: uppercase;
    color: #fff;
    text-shadow: 1px 1px 2px rgba(0,0,0,0.3);
}

.form {
    padding: 2rem;
}

.form-group {
    margin-bottom: 1.5rem;
}

.form-group label {
    display: block;
    font-weight: 500;
    margin-bottom: 0.5rem;
    color: #444;
}

.required {
    color: var(--primary-red);
}

input[type="text"],
input[type="tel"],
textarea {
    width: 100%;
    padding: 0.8rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 6px;
    font-family: inherit;
    font-size: 1rem;
    transition: all 0.3s ease;
    background-color: #fafafa;
}

input:focus,
textarea:focus {
    outline: none;
    border-color: var(--primary-red);
    box-shadow: 0 0 0 3px rgba(218, 37, 29, 0.1);
    background-color: #fff;
}

button {
    width: 100%;
    background-color: var(--primary-red);
    color: var(--primary-yellow);
    border: none;
    padding: 1rem;
    font-size: 1.1rem;
    font-weight: 700;
    text-transform: uppercase;
    border-radius: 6px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 10px;
}

button:hover {
    background-color: var(--dark-red);
    box-shadow: 0 4px 12px rgba(218, 37, 29, 0.3);
}

button:disabled {
    background-color: #ccc;
    color: #666;
    cursor: not-allowed;
    box-shadow: none;
}

/* Loader */
.loader {
    width: 20px;
    height: 20px;
    border: 3px solid rgba(255, 255, 0, 0.3);
    border-radius: 50%;
    border-top-color: var(--primary-yellow);
    animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.status-message {
    margin-top: 1rem;
    padding: 1rem;
    border-radius: 6px;
    text-align: center;
    font-weight: 500;
}

.status-success {
    background-color: #d4edda;
    color: #155724;
    border: 1px solid #c3e6cb;
}

.status-error {
    background-color: #f8d7da;
    color: #721c24;
    border: 1px solid #f5c6cb;
}

@media (max-width: 480px) {
    .titles h1 { font-size: 1rem; }
    .titles h2 { font-size: 1.5rem; }
    .form { padding: 1.5rem; }
}