:root {
    --primary: #003366;
    --primary-light: #004d99;
    --accent: #ffcc00;
    --red: #d00000;
    --bg: #f4f7f6;
    --white: #ffffff;
}

* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Inter', sans-serif; }
body { background-color: var(--bg); color: #333; line-height: 1.5; }

.container { max-width: 1200px; margin: 0 auto; padding: 0 15px; }

/* --- HEADER RESPONSIVE --- */
.header { background: var(--primary); padding: 10px 0; position: sticky; top: 0; z-index: 1000; }
.main-header { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 10px; }
.logo a { font-size: 20px; font-weight: 800; color: white; text-decoration: none; }
.logo span { color: var(--accent); }

.search-box { display: flex; background: white; border-radius: 50px; padding: 2px; flex: 1; min-width: 200px; order: 3; } /* Xuống hàng trên mobile cực nhỏ */
.search-box input { border: none; width: 100%; padding: 8px 15px; outline: none; border-radius: 50px; font-size: 13px; }
.search-box button { background: var(--primary); color: white; border: none; border-radius: 50%; width: 32px; height: 32px; cursor: pointer; }

.cart-icon { color: white; font-size: 20px; position: relative; margin-left: 10px; }
#cart-count { position: absolute; top: -8px; right: -10px; background: var(--accent); color: #000; padding: 1px 5px; border-radius: 50%; font-size: 10px; font-weight: bold; }

/* --- BANNER --- */
.banner { height: 250px; background-size: cover; background-position: center; margin-top: 10px; border-radius: 8px; display: flex; align-items: center; justify-content: center; position: relative; text-align: center; }
.banner::before { content: ''; position: absolute; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.4); border-radius: 8px; }
.banner-content { position: relative; color: white; padding: 0 20px; }
.banner-content h1 { font-size: 1.8rem; font-weight: 800; }
.banner-btn { background: var(--accent); color: #000; padding: 10px 20px; border: none; font-weight: bold; cursor: pointer; margin-top: 15px; border-radius: 50px; font-size: 13px; }

/* --- LAYOUT CHÍNH --- */
.main-layout { display: flex; gap: 20px; margin-top: 20px; }

/* Sidebar trên Mobile sẽ thành thanh trượt ngang */
.sidebar { flex: 0 0 250px; }
.sidebar-box { background: white; padding: 15px; border-radius: 10px; box-shadow: 0 2px 10px rgba(0,0,0,0.05); }
.sidebar-title { font-size: 14px; font-weight: 800; color: var(--primary); margin-bottom: 10px; }
.category-list { list-style: none; display: flex; flex-direction: column; }
.category-list li { padding: 10px 0; border-bottom: 1px solid #f0f0f0; font-size: 13px; cursor: pointer; white-space: nowrap; }
.category-list li.active { color: var(--primary); font-weight: bold; }

.content-area { flex: 1; min-width: 0; }
.section-title h2 { font-size: 16px; font-weight: 800; margin-bottom: 15px; border-left: 4px solid var(--primary); padding-left: 10px; }

/* --- GRID TOUR RESPONSIVE --- */
.product-grid { 
    display: grid; 
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); 
    gap: 20px; 
}

.product-card { background: white; border-radius: 12px; overflow: hidden; border: 1px solid #eee; display: flex; flex-direction: column; transition: 0.3s; }
.img-container { width: 100%; height: 180px; }
.product-img { width: 100%; height: 100%; object-fit: cover; }
.p-details { padding: 15px; flex: 1; display: flex; flex-direction: column; }
.p-title { font-size: 15px; font-weight: 700; height: 40px; overflow: hidden; margin-bottom: 8px; }
.p-price { color: var(--red); font-size: 18px; font-weight: 800; margin-bottom: 12px; }

.btn-group { display: flex; gap: 8px; margin-top: auto; }
.btn-detail { flex: 1; background: #fff; color: var(--primary); border: 1px solid var(--primary); padding: 8px; border-radius: 6px; font-weight: 700; font-size: 12px; text-align: center; text-decoration: none; }
.btn-book { flex: 1.2; background: var(--primary); color: white; border: none; padding: 8px; border-radius: 6px; font-weight: 700; font-size: 12px; cursor: pointer; }

/* --- TRANG CHI TIẾT (DETAIL.HTML) --- */
.detail-layout { display: flex; gap: 30px; flex-direction: row; }
.detail-left, .detail-right { flex: 1; }
.detail-img-large { width: 100%; border-radius: 12px; object-fit: cover; }

/* --- FOOTER RESPONSIVE --- */
.footer { background: #0b132b; color: #cfd8dc; padding: 40px 0 20px; margin-top: 50px; }
.footer-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 30px; }
.footer h3 { color: white; font-size: 15px; margin-bottom: 15px; }
.contact-info p { font-size: 13px; margin-bottom: 10px; display: flex; gap: 8px; }
.footer-bottom { text-align: center; margin-top: 30px; padding-top: 20px; border-top: 1px solid rgba(255,255,255,0.1); font-size: 11px; }

/* --- ADMIN MODAL --- */
.admin-modal { display: none; position: fixed; z-index: 2000; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.7); align-items: center; justify-content: center; padding: 15px; }
.admin-modal.open { display: flex; }
.admin-content { background: white; width: 100%; max-width: 450px; padding: 20px; border-radius: 12px; max-height: 90vh; overflow-y: auto; }

#admin-trigger { position: fixed; bottom: 20px; left: 20px; background: #333; color: white; width: 45px; height: 45px; border-radius: 50%; border: none; z-index: 999; cursor: pointer; }

/* ==========================================
   MÀN HÌNH ĐIỆN THOẠI (DƯỚI 768px)
   ========================================== */
@media (max-width: 768px) {
    .main-header { justify-content: space-between; }
    .logo a { font-size: 18px; }
    .search-box { order: 3; width: 100%; margin-top: 5px; }

    /* Banner nhỏ lại */
    .banner { height: 180px; padding-left: 20px; }
    .banner-content h1 { font-size: 1.4rem; }

    /* CHUYỂN SIDEBAR THÀNH THANH TRƯỢT NGANG */
    .main-layout { flex-direction: column; }
    .sidebar { flex: none; width: 100%; }
    .category-list { 
        flex-direction: row; 
        overflow-x: auto; 
        gap: 15px; 
        padding-bottom: 5px;
    }
    .category-list li { border: none; background: #eee; padding: 8px 15px; border-radius: 20px; flex-shrink: 0; }
    .category-list li.active { background: var(--primary); color: white; }

    /* Tour hiển thị 1 cột to cho dễ nhìn */
    .product-grid { grid-template-columns: 1fr; gap: 15px; }
    
    /* Trang chi tiết xếp dọc */
    .detail-layout { flex-direction: column; }
    
    /* Footer xếp dọc */
    .footer-grid { grid-template-columns: 1fr; gap: 20px; }
}