* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    -webkit-tap-highlight-color: transparent;
}

html, body {
    width: 100%;
    min-height: 100vh;
    min-height: 100dvh;
    background: radial-gradient(circle at top, #144a30 0%, #071710 100%);
    color: #ffffff;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 16px;
}

.register-wrapper {
    width: 100%;
    max-width: 420px;
    display: flex;
    justify-content: center;
}

.Form {
    width: 100%;
    background: linear-gradient(145deg, rgba(17, 42, 31, 0.95), rgba(7, 23, 16, 0.95));
    border: 2px solid #2EB85C;
    border-radius: 20px;
    padding: 30px 24px;
    box-shadow: 0 16px 36px rgba(0, 0, 0, 0.6), 0 0 20px rgba(46, 184, 92, 0.15);
    backdrop-filter: blur(8px);
}

.item.i1 {
    text-align: center;
    margin-bottom: 24px;
}

.item.i1 h2 {
    color: #86efac;
    font-size: 24px;
    font-weight: 800;
    letter-spacing: 1px;
}

.item.i1 .sub-heading {
    color: #9ca3af;
    font-size: 13px;
    margin-top: 4px;
}

.item.i2 {
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.input-group {
    display: flex;
    flex-direction: column;
    gap: 6px;
    text-align: left;
}

.input-group label {
    font-size: 13px;
    font-weight: 600;
    color: #d1fae5;
}

/* Cỡ chữ 16px chống tự động phóng to màn hình trên Safari/Chrome mobile */
.input-group input {
    width: 100%;
    height: 48px;
    padding: 0 14px;
    background: #071710;
    border: 1.5px solid rgba(46, 184, 92, 0.5);
    border-radius: 10px;
    color: #ffffff;
    font-size: 16px;
    outline: none;
    transition: border-color 0.2s, box-shadow 0.2s;
}

.input-group input:focus {
    border-color: #86efac;
    box-shadow: 0 0 0 3px rgba(46, 184, 92, 0.25);
}

.input-group input::placeholder {
    color: #6b7280;
    font-size: 14px;
}

/* Nút bấm chuẩn touch target 48px */
.dang-ky {
    width: 100%;
    height: 48px;
    background: linear-gradient(135deg, #2EB85C 0%, #15803d 100%);
    color: #071710;
    font-size: 16px;
    font-weight: 800;
    border: none;
    border-radius: 10px;
    cursor: pointer;
    box-shadow: 0 4px 12px rgba(46, 184, 92, 0.3);
    transition: transform 0.1s, filter 0.2s;
    margin-top: 4px;
}

.dang-ky:hover {
    filter: brightness(1.08);
}

.dang-ky:active {
    transform: scale(0.98);
}

/* Vùng thông báo lỗi/thành công */
#msg {
    font-size: 13px;
    font-weight: bold;
    min-height: 18px;
    text-align: center;
    margin-top: -4px;
}

.switch-auth {
    text-align: center;
    font-size: 13.5px;
    color: #9ca3af;
    margin-top: 6px;
}

.switch-auth a {
    color: #86efac;
    text-decoration: none;
    font-weight: 700;
    margin-left: 4px;
}

.switch-auth a:hover {
    text-decoration: underline;
}

/* Điện thoại màn hình nhỏ (< 400px) */
@media screen and (max-width: 400px) {
    .Form {
        padding: 24px 16px;
    }
    .item.i1 h2 {
        font-size: 21px;
    }
}