/* ===== Base & Typography ==================================== */
:root {
    --font-sans: 'Inter', 'Noto Sans', 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

/* Cỡ chữ: mobile 14px, >=768px 16px */
html {
    font-size: 14px;
    position: relative;
    min-height: 100%;
}

@media (min-width:768px) {
    html {
        font-size: 16px;
    }
}

body {
    margin-bottom: 60px;
    font-family: var(--font-sans);
    line-height: 1.55;
    color: var(--text-color);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Headings đồng bộ */
h1, h2, h3 {
    font-weight: 600;
}

h2, h4 {
    color: #1f2a44;
    margin: 0 0 18px;
}

h4 {
    margin-top: 28px;
}

/* ===== Form container ======================================= */
/* KHÔNG đặt font riêng ở form để tránh lệch font */
form {
    max-width: 760px;
    margin: 32px auto;
    padding: 24px;
    background: #fff;
    border: 1px solid #e9eef5;
    border-radius: 12px;
    box-shadow: 0 6px 18px rgba(10,30,66,.06);
}

/* Section divider */
hr {
    border: 0;
    border-top: 1px solid #eef2f7;
    margin: 24px 0;
}

/* ===== Controls ============================================= */
.form-group {
    margin-bottom: 16px;
}

label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: #27324a;
    margin-bottom: 6px;
}

/* Mọi control kế thừa cùng stack font */
input, select, textarea, button {
    font-family: inherit;
}

.form-control, select, input[type="text"], input[type="email"],
input[type="tel"], input[type="number"], input[type="date"] {
    display: block;
    width: 100%;
    height: 44px;
    padding: 10px 12px;
    border: 1px solid #cfd7e6;
    border-radius: 8px;
    background: #fff;
    font-size: 15px;
    line-height: 1.2;
    box-sizing: border-box;
    transition: border-color .15s ease, box-shadow .15s ease;
}

.form-control:focus, select:focus, input[type="date"]:focus {
    outline: none;
    border-color: #4d79c7;
    box-shadow: 0 0 0 3px rgba(77,121,199,.15);
}

.text-danger, .field-validation-error {
    color: #c0392b;
    font-size: 13px;
}

/* ===== Radios / checkboxes ================================== */
.form-check {
    display: flex;
    align-items: center;
    gap: 8px;
    margin: 6px 14px 6px 0;
}

.d-flex.gap-3 {
    gap: 14px !important;
    flex-wrap: wrap;
}

.form-check-input {
    width: 18px;
    height: 18px;
    margin: 0;
    border: 2px solid #cfd7e6;
    border-radius: 50%;
    appearance: none;
    cursor: pointer;
    position: relative;
}

.form-check-input:checked {
    background: #4d79c7;
    border-color: #4d79c7;
}

.form-check-input:checked::after {
    content: "";
    position: absolute;
    inset: 4px;
    border-radius: 50%;
    background: #fff;
}

/* ===== Văn bằng block ======================================= */
.vanbang-block {
    border: 1px solid #e6ebf4;
    border-radius: 10px;
    padding: 18px;
    margin-bottom: 16px;
}

.vanbang-block h5 {
    margin: 0 0 14px;
    font-size: 15px;
    font-weight: 700;
    color: #2b5fb8;
    background: #f3f7ff;
    padding: 8px 12px;
    border-radius: 8px;
}

/* ===== Buttons ============================================== */
.btn {
    display: inline-block;
    padding: 11px 22px;
    border-radius: 10px;
    border: 0;
    font-weight: 650;
    text-decoration: none;
    cursor: pointer;
    transition: transform .05s ease, opacity .15s ease, box-shadow .15s ease;
}

.btn:active {
    transform: translateY(1px);
}

.btn-primary {
    background: #316bd6;
    color: #fff;
    box-shadow: 0 6px 12px rgba(49,107,214,.18);
}

.btn-primary:hover {
    opacity: .92;
}

/* Focus ring đồng bộ */
.btn:focus, .btn:active:focus, .btn-link.nav-link:focus,
.form-control:focus, .form-check-input:focus {
    box-shadow: 0 0 0 0.1rem #fff, 0 0 0 0.25rem #258cfb;
}

/* ===== Small helpers ======================================== */
#txtKhac {
    margin-top: 8px;
}

#vanbang-container {
    margin-top: 18px;
}

/* ===== Responsive =========================================== */
@media (max-width:640px) {
    form {
        margin: 16px;
        padding: 18px;
    }
}

/* A11y: ẩn thị giác, vẫn đọc bằng screen reader */
.visually-hidden {
    position: absolute !important;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0,0,0,0);
    white-space: nowrap;
    border: 0;
}