:root {
    --font-family: 'Inter', sans-serif;
    --font-color: #FFFFFF;
    --background-color: #333333;
    --background-image: none;
    --blur-intensity: 10px;
}

body {
    font-family: var(--font-family);
    color: var(--font-color);
    background-color: var(--background-color);
    min-height: 100vh;
    margin: 0;
    display: flex;
    flex-direction: column;
    position: relative;
}

.background-layer {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    z-index: 1;
    background-image: var(--background-image);
    background-size: cover;
    background-position: center;
}

.background-layer.blur {
    filter: blur(var(--blur-intensity));
}

.overlay {
    position: absolute;
    top: 0;
    right: 0;
    bottom: 0;
    left: 0;
    background-color: rgba(0, 0, 0, 0.5);
    z-index: 2;
}

main {
    flex-grow: 1;
    position: relative;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem;
}

.content {
    position: relative;
    z-index: 10;
    text-align: center;
    max-width: 600px;
    width: 100%;
}

.logo {
    max-width: 100%;
    margin-bottom: 2rem;
}

h1 {
    font-size: clamp(1.5rem, 5vw, 3rem);
    font-weight: 700;
    margin-bottom: 1rem;
    line-height: 1.2;
    color: var(--font-color) !important;
}

p {
    font-size: 1rem;
    color: var(--font-color);
    margin-bottom: 0.1rem !important;
    opacity: 0.8;
}

.countdown {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-bottom: 2rem;
    box-sizing: content-box; /* Ghi đè box-sizing từ Bootstrap */
}

.countdown > div {
    background: rgba(255, 255, 255, 0.1);
    backdrop-filter: blur(4px);
    border-radius: 0.5rem;
    padding: 1rem;
    text-align: center;
    min-width: 60px;
    box-sizing: content-box; /* Đảm bảo padding không làm co nội dung */
}

.countdown .value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--font-color);
    box-sizing: content-box; /* Đảm bảo cho các phần tử con */
}

.countdown .label {
    font-size: 0.75rem;
    color: var(--font-color);
    opacity: 0.7;
    box-sizing: content-box; /* Đảm bảo cho các phần tử con */
}

form {
    display: flex;
    justify-content: center;
    gap: 0.5rem;
    max-width: 400px;
    margin: 0 auto 1rem;
    flex-wrap: nowrap;
}

#contact-form input {
    flex-grow: 1;
    padding: 0.375rem 0.75rem;
    border-radius: 0;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--font-color);
    height: 38px;
    line-height: 1.5;
    box-sizing: border-box;
    min-width: 0;
    max-width: 200px;
}

#contact-form input::placeholder {
    color: var(--font-color);
    opacity: 0.7;
}

#contact-form button {
    padding: 0.575rem 1.75rem;
    background-color: #007bff;
    border-radius: 0;
    font-weight: 400;
    transition: background-color 0.2s, border-color 0.2s;
    color: #fff;
    height: 38px;
    line-height: 1.5;
    text-align: center;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    box-sizing: border-box;
    white-space: nowrap;
    min-width: 0;
    max-width: 150px;
    font-size: 0.875rem;
}

#contact-form button:hover {
    background-color: #0056b3;
    border-color: #0056b3;
}

button {
    padding: 0.375rem 0.75rem;
    background-color: #007bff;
    border-radius: 0.5rem;
    font-weight: 400;
    transition: background-color 0.2s, border-color 0.2s;
    color: #fff;
    min-width: 100px;
    text-align: center;
}

button:hover {
    background-color: #0056b3;
    border-color: #0056b3;
}

.text-xs {
    font-size: 0.75rem;
    color: var(--font-color);
    margin-top: 0.25rem;
    margin-bottom: 0;
    opacity: 0.7;
    text-align: center;
}

.recaptcha-notice {
    font-size: 0.75rem;
    color: var(--font-color);
    margin-top: 0;
    opacity: 0.7;
    text-align: center;
}

.recaptcha-notice a {
    color: var(--font-color);
    text-decoration: underline;
}

.recaptcha-notice a:hover {
    color: #fff;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 1rem;
    margin-top: 1rem;
}

.social-links a {
    display: inline-flex;
    align-items: center;
}

.social-links svg {
    width: 1.5rem;
    height: 1.5rem;
    fill: var(--font-color);
    transition: fill 0.2s;
}

.social-links a:hover svg {
    fill: #fff;
}

footer {
    padding: 1.5rem 0;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
}

footer .text-sm {
    font-size: 0.875rem;
    color: var(--font-color);
    text-align: center;
    opacity: 0.7;
}

.progress {
    max-width: 100%;
    margin: 1.5rem auto;
    background-color: rgba(255, 255, 255, 0.2);
    border-radius: 5px;
    overflow: hidden;
}

.progress-bar {
    height: 20px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--font-color);
    font-size: 12px;
    font-weight: bold;
    transition: width 0.3s ease-in-out;
}

.grecaptcha-badge {
    visibility: hidden;
}

/* Responsive adjustments */
@media (max-width: 768px) {
    p {
        font-size: 1.25rem;
    }
    .countdown .value {
        font-size: 2rem;
    }
    .progress {
        max-width: 90%;
        margin: 1rem auto;
    }
}

@media (max-width: 640px) {
    .countdown {
        gap: 0.5rem;
    }
    .countdown > div {
        padding: 0.5rem;
        min-width: 50px;
        box-sizing: content-box; /* Giữ content-box trên màn hình nhỏ */
    }
    .countdown .value {
        font-size: 1.25rem;
    }
    .countdown .label {
        font-size: 0.625rem;
    }
}

@media (max-width: 576px) {
    main {
        padding: 1rem;
    }
    .content {
        max-width: 90%;
    }
    .logo {
        max-width: 80%;
        margin-bottom: 1.5rem;
    }
    h1 {
        font-size: clamp(1.25rem, 4vw, 2rem);
    }
    p {
        font-size: 0.875rem;
        margin-bottom: 1.5rem;
    }
    form {
        gap: 0.3rem;
        max-width: 100%;
        flex-wrap: nowrap;
    }
    #contact-form input {
        height: 38px;
        min-width: 0;
        max-width: 45%;
        padding: 0.375rem 0.5rem;
        border-radius: 0;
    }
    #contact-form button {
        height: 38px;
        padding: 0.375rem 0.5rem;
        min-width: 0;
        max-width: 45%;
        font-size: 0.75rem;
        border-radius: 0;
    }
    .text-xs,
    .recaptcha-notice {
        font-size: 0.625rem;
    }
    .social-links {
        gap: 0.75rem;
    }
    .social-links svg {
        width: 1.25rem;
        height: 1.25rem;
    }
    footer .text-sm {
        font-size: 0.75rem;
    }
    .progress {
        max-width: 85%;
        margin: 0.75rem auto;
    }
}

@media (max-width: 400px) {
    main {
        padding: 0.75rem;
    }
    .content {
        max-width: 95%;
    }
    .logo {
        max-width: 70%;
        margin-bottom: 1rem;
    }
    h1 {
        font-size: clamp(1rem, 3.5vw, 1.5rem);
    }
    form {
        gap: 0.1rem;
        flex-wrap: nowrap;
    }
    #contact-form input {
        height: 38px;
        min-width: 0;
        max-width: 40%;
        padding: 0.375rem 0.3rem;
        border-radius: 0;
    }
    #contact-form button {
        height: 38px;
        min-width: 0;
        max-width: 40%;
        padding: 0.375rem 0.3rem;
        font-size: 0.65rem;
        border-radius: 0;
    }
    .countdown {
        gap: 0.25rem;
    }
    .countdown > div {
        padding: 0.5rem;
        min-width: 40px;
        box-sizing: content-box; /* Giữ content-box trên màn hình rất nhỏ */
    }
    .countdown .value {
        font-size: 1rem;
    }
    .countdown .label {
        font-size: 0.5rem;
    }
    .social-links {
        gap: 0.75rem;
    }
    .social-links svg {
        width: 1.25rem;
        height: 1.25rem;
    }
}