:root {
    --imexco-blue: #0056b3; 
    --imexco-dark: #003d7a;
    --bg-light: #f4f7fa;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body, html {
    height: 100%;
    margin: 0;
    font-family: 'Inter', sans-serif;
    display: flex;
    align-items: center;
    justify-content: center;
}

/* Nền dốc hiện đại thay vì mảng màu đặc */
body::before {
    content: "";
    position: absolute;
    top: 0; left: 0; right: 0;
    height: 100%;
   
    z-index: 0;
}

.auth-card {
    background: #ffffff;
    border-radius: 20px;
    padding: 2.5rem;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.1);
    width: 85%;
    max-width: 400px;
    position: relative;
    z-index: 1;
    border: 1px solid rgba(255, 255, 255, 0.3);
}

/* Logo & Header */
.logo-text { 
    color: var(--imexco-blue); 
    font-weight: 800; 
    font-size: 32px; 
    letter-spacing: -0.5px; 
    margin: 0; 
}
.tagline { 
    font-size: 10px; 
    color: #adb5bd; 
    text-transform: uppercase; 
    letter-spacing: 3px; 
    font-weight: 600;
}

.logo {
    width: 150px;
    height: auto;
}

/* Input styling */
.form-label { 
    font-weight: 600; 
    color: #495057; 
    font-size: 0.75rem; 
    margin-bottom: 8px; 
    text-transform: uppercase;
}

.form-control { 
    border-radius: 12px; 
    padding: 14px 16px; 
    border: 2px solid #edf2f7; 
    font-size: 1rem; 
    transition: var(--transition);
    background-color: #f8f9fa;
}

.form-control:focus { 
    border-color: var(--imexco-blue); 
    background-color: #fff;
    box-shadow: 0 0 0 4px rgba(0, 86, 179, 0.1);
    outline: none;
}

/* Nút bấm hiện đại */
.btn-imexco {
    background-color: var(--imexco-blue);
    border: none;
    border-radius: 12px;
    padding: 14px;
    font-weight: 700;
    width: 100%;
    color: white;
    letter-spacing: 0.5px;
    transition: var(--transition);
    box-shadow: 0 4px 12px rgba(0, 86, 179, 0.2);
}

.btn-imexco:hover {
    background-color: var(--imexco-dark);
    transform: translateY(-1px);
    box-shadow: 0 6px 15px rgba(0, 86, 179, 0.3);
    color: #fff;
}

.btn-imexco:active { transform: translateY(0); }

/* OTP Input cụ thể */
#otp {
    letter-spacing: 12px;
    font-weight: 700;
    font-size: 1.5rem;
    text-indent: 12px; /* Căn giữa text khi có letter-spacing */
}

.instruction-text { 
    font-size: 0.9rem; 
    color: #6c757d; 
    line-height: 1.5;
}

#countdown {
    font-variant-numeric: tabular-nums;
    font-weight: 600;
    color: var(--imexco-blue);
}

.btn-link { 
    color: #6c757d; 
    text-decoration: none; 
    font-size: 0.85rem; 
    font-weight: 500;
    transition: var(--transition);
}

.btn-link:disabled {
    color: #ccc !important;
    cursor: not-allowed;
    text-decoration: none;
}

.btn-link:hover { color: var(--imexco-blue); }

.admin-badge {
    background: #f8f9fa;
    color: #666;
    font-size: 0.7rem;
    letter-spacing: 2px;
    padding: 4px 12px;
    border-radius: 50px;
    display: inline-block;
    margin-bottom: 15px;
    border: 1px solid #eee;
}

/* Animation chuyển cảnh nhẹ */
.fade-in {
    animation: fadeIn 0.4s ease-out;
}


@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}