/* Reset mặc định và font */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Poppins', sans-serif;
    background: linear-gradient(135deg, #94b83d8f 0%, #ace5d7 100%);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
    padding: 20px;
    overflow: hidden;
}

.container {
    position: relative;
    width: 100%;
    max-width: 500px;
    padding: 0;
}

.card {
    background: rgba(255, 255, 255, 0.95);
    border-radius: 20px;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.15);
    animation: slideUp 0.8s ease-out;
    backdrop-filter: blur(10px);
    margin: 0;
    border: none;
}

@keyframes slideUp {
    0% {
        opacity: 0;
        transform: translateY(50px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

.card-header {
    background: linear-gradient(90deg, #3498db, #2980b9);
    border-radius: 20px 20px 0 0;
    padding: 15px 20px;
    text-align: center;
}

.card-title {
    font-size: 1.8rem;
    font-weight: 600;
    color: #fff;
    margin: 0;
    letter-spacing: 1px;
}

.card-body {
    padding: 30px;
}

p.mb-3 {
    font-size: 1rem;
    color: #7f8c8d;
    text-align: center;
    margin-bottom: 20px;
}

/* Input field */
.form-control {
    font-size: 1rem;
    padding: 12px 15px 12px 40px; /* Để dành chỗ cho icon */
    border-radius: 10px;
    border: 1px solid #dfe6e9;
    background: #f9fbfc;
    transition: all 0.3s ease;
    position: relative;
}

.form-control:focus {
    border-color: #3498db;
    box-shadow: 0 0 12px rgba(52, 152, 219, 0.3);
    background: #fff;
}

.form-control::placeholder {
    color: #95a5a6;
}

.mb-3 {
    position: relative;
    margin-bottom: 20px;
}

.mb-3 i {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: #95a5a6;
    font-size: 1.1rem;
}

.form-label {
    font-size: 0.95rem;
    color: #2c3e50;
    margin-bottom: 5px;
}

/* Nút bấm */
.btn-primary {
    width: 100%;
    padding: 14px;
    font-size: 1.1rem;
    font-weight: 500;
    background: linear-gradient(90deg, #3498db, #2980b9);
    border: none;
    border-radius: 10px;
    color: #fff;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: all 0.4s ease;
}

.btn-primary:hover {
    background: linear-gradient(90deg, #2980b9, #1f618d);
    transform: translateY(-3px);
    box-shadow: 0 8px 20px rgba(52, 152, 219, 0.4);
}

/* Alert thông báo */
.alert-danger {
    color: #fff;
    background: linear-gradient(90deg, #e74c3c, #c0392b);
    padding: 12px;
    border-radius: 8px;
    margin-bottom: 20px;
    font-size: 0.9rem;
    box-shadow: 0 4px 15px rgba(231, 76, 60, 0.3);
}

.alert-success {
    color: #fff;
    background: linear-gradient(90deg, #2ecc71, #27ae60);
    padding: 15px;
    border-radius: 8px;
    margin-bottom: 0;
    font-size: 1rem;
    text-align: center;
    box-shadow: 0 4px 15px rgba(46, 204, 113, 0.3);
}

.alert-success .btn-primary {
    margin-top: 10px;
    padding: 10px 20px;
    font-size: 1rem;
}

/* Ẩn/hiện các bước */
.hidden {
    display: none;
}

/* Responsive */
@media (max-width: 576px) {
    .card {
        padding: 20px;
    }
    .card-title {
        font-size: 1.5rem;
    }
    .form-control {
        font-size: 0.95rem;
    }
    .btn-primary {
        padding: 12px;
        font-size: 1rem;
    }
}