:root {
    --primary-color: #1d0199;
    --light-bg: #f8f9fa;
    --light-grey-bg: #f1f1f1;
    --border-color: #dee2e6;
    --text-dark: #212529;
    --danger-color: #ff0000;
    --glow-light: rgba(255, 255, 255, 0.3);
    --glow-strong: rgba(255, 255, 255, 0.7);
    --overlay-dark: rgba(0, 0, 0, 0.5);
}

body {
    font-family: Lato, sans-serif;
}

.small-logo {
    max-width: 2em;
    height: auto;
}

a.facebook-icon {
    width: 36px;
    height: 36px;
    background-color: #fff;
    border-radius: 50%;
    flex-shrink: 0;
}

i.facebook-icon {
    color: #2100ff;
    font-size: 1rem;
}

.large-logo {
    max-width: 25em;
    height: auto;
}

#introduce {
    min-height: 50em;
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    text-align: center;
    position: relative;
}

#introduce .info {
    position: absolute;
    bottom: 20px;
    left: 20px;
    right: 20px;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

#introduce .info p {
    margin: 0;
}

@media screen and (max-width: 768px) {
    #introduce {
        flex-direction: column;
    }
}

.background-img {
    position: relative;
    background: url(../img/background.webp) center/cover no-repeat;
}

.background-img::before {
    content: "";
    position: absolute;
    inset: 0;
    background: var(--overlay-dark);
    z-index: 1;
}

.background-img > * {
    position: relative;
    z-index: 2;
}

#navbar {
    width: 100%;
    left: 0;
    z-index: 1001;
    background-color: #000;
    box-shadow: 0 2px 10px rgba(255, 255, 255, 0.1);
}

.opening-hours {
    background: var(--glow-light);
    padding: 15px;
    border-radius: 10px;
    border: 2px solid var(--glow-light);
    box-shadow: 0 0 10px var(--glow-strong);
    text-align: center;
    font-weight: 700;
    font-size: 1.2em;
    color: #fff;
    display: inline-block;
    animation: glow 1.5s infinite alternate;
}

@keyframes glow {
    from {
        box-shadow: 0 0 5px var(--glow-light);
    }
    to {
        box-shadow: 0 0 20px var(--glow-strong);
    }
}

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}
.bg-light-gray {
    background-color: var(--light-grey-bg);
}

/* menu */

.menu-bar {
    display: flex;
    margin: 0 auto;
    max-width: 40em;
    border: var(--primary-color) solid 1px;
}

.menu-item {
    position: relative;
    display: flex;
    flex-direction: column;
    align-items: center;
    border: none;
    background: transparent;
    cursor: pointer;
    flex: 1;
}

.menu-icon {
    font-size: 20px;
    color: #555;
    margin-bottom: 4px;
}

.menu-label {
    font-size: 11px;
    font-weight: 500;
    color: #333;
    text-transform: uppercase;
    text-align: center;
    line-height: 1.2;
}

/* Active State */
.menu-item.active {
    background-color: blue;
}
.menu-item.active .menu-icon,
.menu-item.active .menu-label {
    color: white;
}
/* Ẩn chữ khi màn hình nhỏ */
@media (max-width: 480px) {
    .menu-label {
        display: none;
    }
    
    .menu-item {
        padding: 10px 2px;
        min-width: 44px;
    }
    
    .menu-icon {
        margin-bottom: 0;
    }
}

/* Desktop */
@media (min-width: 768px) {
    .menu-item {
        padding: 12px 8px;
    }
    
    .menu-icon {
        font-size: 22px;
    }
    
    .menu-label {
        font-size: 12px;
    }
}
#menuContent {
    max-width: 40em;
    margin: 0 auto;
    display: block;
    width: 100%;
}

/* category-header */
.category-header{
    margin-top: 1em;
}
.category-price, .item-price, .option-price {
    font-weight: bold;
}
.item-title {
    font-size: 1.2rem;
    font-weight: bold;
}
.category-note {
    font-size: 1.0rem;
    font-weight: bold;
}
.item-note, .option-note {
    font-size: 0.7rem;
    font-weight: bold;
}
.item-header {
    margin-top: 1em;
}
.border-bottom-price {
    border-bottom: 1px solid var(--primary-color);
    padding-bottom: 4px;
    margin-bottom: 8px;
}

/* backToTopBtn */
#backToTopBtn {
    display: none;
    position: fixed;
    bottom: 40px;
    right: 30px;
    z-index: 999;
    font-size: 16px;
    font-weight: 600;
    border: none;
    outline: none;
    background-color: #0d6efd;
    color: white;
    cursor: pointer;
    padding: 12px 24px 12px 18px; 
    border-radius: 50px;
    transition: all 0.4s ease-out;
    box-shadow: 0 4px 15px rgba(13, 110, 253, 0.3);
    align-items: center;
    gap: 10px;
}

#backToTopBtn::before {
    content: "⬆";
    display: inline-block;
    font-size: 22px;
    font-weight: bold;
    color: var(--danger-color);
    background: var(--light-bg);
    width: 36px;
    height: 36px;
    line-height: 36px;
    border-radius: 50%;
    text-align: center;
    transition: all 0.3s ease;
    margin-right: 5px;
}

#backToTopBtn:hover::before {
    background: rgba(255, 255, 255, 0.3);
    transform: scale(1.1) translateY(-3px);
    text-shadow: 0 2px 5px rgba(0, 0, 0, 0.2);
}

/* Hiệu ứng ánh sáng cho mũi tên */
#backToTopBtn:hover::after {
    content: "";
    position: absolute;
    left: 18px;
    top: 50%;
    width: 10px;
    height: 10px;
    background: radial-gradient(circle, rgba(255,255,255,0.8) 0%, rgba(255,255,255,0) 70%);
    transform: translate(-50%, -50%);
    opacity: 0;
    animation: shine 1.5s infinite;
}

@keyframes shine {
    0% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(0.5);
    }
    50% {
        opacity: 0.4;
    }
    100% {
        opacity: 0;
        transform: translate(-50%, -50%) scale(1.5);
    }
}

/* Animation khi hiển thị */
#backToTopBtn.show {
    display: flex;
    animation: bounceIn 0.6s;
}

@keyframes bounceIn {
    0% {
        opacity: 0;
        transform: translateY(50px) scale(0.7);
    }
    50% {
        transform: translateY(-10px) scale(1.05);
    }
    80% {
        transform: translateY(0) scale(0.95);
    }
    100% {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

/* Responsive */
@media (max-width: 768px) {
    #backToTopBtn::before {
        font-size: 20px;
        width: 32px;
        height: 32px;
        line-height: 32px;
    }
}