/* ================== GLOBAL ================== */
body {
    font-family: 'Segoe UI', Arial, sans-serif;
    margin: 0;
    padding: 0;
    min-height: 100vh;

    /* nền cổ trang */
    background: radial-gradient(circle at top, #2b1b12, #0b0705);
    color: #f5e6c8;
}

/* ================== MENU ================== */
.menu-icon {
    display: none;
    font-size: 26px;
    cursor: pointer;

    background: linear-gradient(to bottom, #8b5a2b, #3b2415);
    color: #fff3d1;
    border: none;
    padding: 12px;
    width: 100%;
    text-align: center;
}

.navbar {
    display: flex;
    justify-content: center;

    background: linear-gradient(to bottom, #5a2d0c, #2a1406);
    box-shadow: 0 4px 15px rgba(0,0,0,0.7);

    border-bottom: 2px solid #d4af37; /* vàng kim */
    position: relative;
    z-index: 20;
}

.navbar a {
    position: relative;
    color: #f5e6c8;
    padding: 15px 28px;
    text-decoration: none;
    font-weight: bold;
    transition: all 0.3s;
}

.navbar a::after {
    content: "";
    position: absolute;
    left: 10%;
    bottom: 8px;
    width: 0;
    height: 2px;
    background: #d4af37;
    transition: width 0.3s;
}

.navbar a:hover {
    background: linear-gradient(to bottom, #a86b2b, #5a2d0c);
    color: #fff;
}

.navbar a:hover::after {
    width: 80%;
}

/* ================== CONTAINER ================== */
.container {
    position: relative;
    overflow: hidden;

    padding: 30px;
    max-width: 520px;
    margin: 40px auto;

    background: linear-gradient(to bottom, #2a1406, #120903);
    border-radius: 14px;

    border: 2px solid #d4af37;

    box-shadow:
        0 0 25px rgba(212,175,55,0.15),
        inset 0 0 20px rgba(0,0,0,0.8);

    z-index: 5;
}

/* ánh sáng cổ trang */
.container::after {
    content: "";
    position: absolute;
    inset: 0;
    border-radius: 14px;

    background:
        linear-gradient(45deg,
            transparent 30%,
            rgba(212,175,55,0.08),
            transparent 70%);

    animation: glowmove 6s linear infinite;
    z-index: 0;
}

@keyframes glowmove {
    0% { transform: translateX(-50px); }
    100% { transform: translateX(50px); }
}

/* ================== TITLE ================== */
h1 {
    text-align: center;
    margin-bottom: 25px;

    font-size: 1.9em;
    color: #d4af37; /* vàng kim */
    text-shadow: 0 0 10px rgba(212,175,55,0.6);
}

h3 {
    text-align: center;
    margin: 20px 0 10px;
    color: #f0c36a;
}

/* ================== TABLE ================== */
table {
    width: 100%;
    border-collapse: collapse;
    margin: 20px 0;
}

td {
    padding: 12px 0;
}

td:first-child {
    font-weight: bold;
    color: #f0c36a;
}

/* ================== INPUT ================== */
input[type="text"],
input[type="password"] {
    width: 100%;
    padding: 12px;

    background-color: #120903;
    border: 1px solid #d4af37;
    border-radius: 8px;

    color: #f5e6c8;
    transition: all 0.3s;

    position: relative;
    z-index: 10;
}

input::placeholder {
    color: #a88b5c;
}

input:focus {
    outline: none;
    border-color: #fff3d1;
    box-shadow: 0 0 10px rgba(212,175,55,0.4);
}

/* ================== CAPTCHA ================== */
.captcha {
    display: flex;
    align-items: center;
    gap: 10px;
    margin: 15px 0;
}

.captcha img {
    border: 2px solid #d4af37;
    border-radius: 8px;
    background: #000;
}

/* ================== BUTTON ================== */
input[type="submit"] {
    width: 100%;
    padding: 15px;

    background: linear-gradient(to bottom, #d4af37, #8b6b1f);
    color: #1a0f05;

    border: 2px solid #f0c36a;
    border-radius: 10px;

    cursor: pointer;
    font-size: 1.15em;
    font-weight: bold;

    margin-top: 25px;
    transition: all 0.3s;

    position: relative;
    z-index: 10;
}

input[type="submit"]:hover {
    background: linear-gradient(to bottom, #ffe08a, #d4af37);
    box-shadow: 0 0 15px rgba(212,175,55,0.6);
}

/* ================== FOOTER ================== */
footer {
    background: linear-gradient(to bottom, #1a0d06, #0b0705);
    color: #d4af37;

    text-align: center;
    padding: 20px;
    margin-top: 50px;

    border-top: 2px solid #d4af37;
}

footer a {
    color: #f0c36a;
}

/* ================== MOBILE ================== */
@media (max-width: 768px) {
    .menu-icon { display: block; }
    .navbar { flex-direction: column; display: none; }
    .navbar.show { display: flex; }
    .container { margin: 20px; padding: 20px; }
    .captcha { flex-direction: column; }
}