/* ================= 1. BIẾN MÀU & THIẾT LẬP CHUNG ================= */
:root {
  --primary: #172B4D;       /* Xanh navy: Header, Footer, Nút chính */
  --accent: #722F37;        /* Đỏ rượu: Nút phụ, Điểm nhấn */
  --accent-hover: #800020;  /* Màu đỏ đậm khi rê chuột */
  --bg-body: #F8FAFC;       /* Màu nền trang */
  --bg-card: #FFFFFF;       /* Nền khung thẻ */
  --text-main: #2C221E;     /* Màu chữ chính */
  --text-muted: #6E5D53;    /* Màu chữ phụ */
}

* { margin: 0; padding: 0; box-sizing: border-box; }
body { font-family: 'Segoe UI', Tahoma, Geneva, sans-serif; background-color: var(--bg-body); color: var(--text-main); line-height: 1.6; }
main { max-width: 1100px; margin: 30px auto; padding: 0 20px; }

/* ================= 2. HEADER & MENU ĐIỀU HƯỚNG ================= */
header {
  background-color: var(--primary);
  padding: 12px 6%;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: relative;
  box-shadow: 0 4px 12px rgba(0,0,0,0.1);
}
.logo img { height: 60px; background: #fff; padding: 4px; border-radius: 8px; display: block; }
.menu { display: flex; align-items: center; gap: 24px; margin-left: auto; margin-right: 25px; }
.menu a {
  color: #fff; text-decoration: none; font-size: 16px; font-weight: 500;
  padding: 6px 12px; border-radius: 6px; transition: 0.3s;
}
.menu a:hover, .menu a.active { background: rgba(255,255,255,0.15); }

.account-btns { display: flex; gap: 12px; }
.account-btns a, .mobile-auth a {
  text-decoration: none; font-size: 14px; font-weight: 600;
  padding: 8px 18px; border-radius: 20px; transition: 0.3s;
}
.btn-login { color: #fff; border: 1.5px solid var(--accent); }
.btn-login:hover { background: var(--accent); }
.btn-register { background: var(--accent); color: #fff; }
.btn-register:hover { background: var(--accent-hover); }

/* Nút Hamburger (Mobile) */
.hamburger {
  display: none; flex-direction: column; gap: 5px;
  background: none; border: 1px solid #fff; padding: 8px; border-radius: 6px; cursor: pointer;
}
.hamburger span { width: 24px; height: 2px; background: #fff; }

/* ================= 3. KHUNG CHÀO MỪNG & TÌM KIẾM (TRANG CHỦ) ================= */
.welcome-box {
  background: linear-gradient(135deg, #F3ECE3, #E6D7C3);
  padding: 40px 20px; border-radius: 16px; text-align: center;
  box-shadow: 0 4px 15px rgba(0,0,0,0.05);
}
.welcome-box p { font-size: 18px; color: var(--primary); max-width: 650px; margin: 0 auto 20px; font-weight: 500; }
.search-form { display: flex; justify-content: center; gap: 10px; max-width: 500px; margin: 0 auto; }
.search-form input {
  flex: 1; padding: 12px 20px; border: 1.5px solid #D5C7B8; border-radius: 25px;
  font-size: 15px; outline: none;
}
.search-form input:focus { border-color: var(--accent); }
.search-form button {
  background: var(--accent); color: #fff; border: none; padding: 12px 24px;
  border-radius: 25px; font-weight: 600; cursor: pointer; transition: 0.3s;
}
.search-form button:hover { background: var(--accent-hover); }

/* ================= 4. DANH SÁCH SÁCH NỔI BẬT (GRID) ================= */
.section-title { text-align: center; color: var(--primary); font-size: 26px; margin: 40px 0 25px; position: relative; }
.section-title::after {
  content: ""; display: block; width: 50px; height: 3px; background: var(--accent);
  margin: 8px auto 0; border-radius: 2px;
}
.book-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(230px, 1fr));
  gap: 25px; margin-bottom: 50px;
}
.book-card {
  background: var(--bg-card); border: 1px solid #EFEAE4; border-radius: 12px;
  padding: 18px; text-align: center; display: flex; flex-direction: column;
  justify-content: space-between; align-items: center; box-shadow: 0 4px 12px rgba(0,0,0,0.04);
  transition: transform 0.3s, box-shadow 0.3s;
}
.book-card:hover { transform: translateY(-5px); box-shadow: 0 10px 20px rgba(0,0,0,0.08); }
.book-card img { width: 170px; height: 235px; object-fit: cover; border-radius: 6px; margin-bottom: 12px; }
.book-card h3 {
  font-size: 16px; color: var(--primary); min-height: 44px;
  display: flex; align-items: center; justify-content: center; margin-bottom: 12px;
}
.book-card .btn-download {
  width: 100%; background: var(--primary); color: #fff; border: none;
  padding: 9px; border-radius: 20px; cursor: pointer; font-weight: 500; transition: 0.3s;
}
.book-card .btn-download:hover { background: var(--accent); }

/* ================= 5. TRANG GIỚI THIỆU ================= */
.banner-intro { width: 100%; max-height: 480px; object-fit: cover; border-radius: 12px; margin-bottom: 30px; }
.intro-content h2 { color: var(--primary); font-size: 22px; border-left: 4px solid var(--accent); padding-left: 12px; margin: 25px 0 10px; }
.intro-content p { color: var(--text-muted); font-size: 16px; line-height: 1.8; }
.feature-list { display: grid; grid-template-columns: repeat(2, 1fr); gap: 15px; list-style: none; margin: 15px 0 30px; }
.feature-list li {
  background: var(--bg-card); border: 1px solid #E8DED3; border-radius: 8px;
  padding: 14px 18px 14px 40px; position: relative; transition: 0.3s;
}
.feature-list li::before { content: "✦"; color: var(--accent); position: absolute; left: 16px; top: 14px; font-weight: bold; }
.feature-list li:hover { border-color: var(--accent); transform: translateY(-2px); }

/* ================= 6. TRANG LIÊN HỆ ================= */
.contact-container { background: var(--bg-card); padding: 35px; border-radius: 14px; box-shadow: 0 4px 15px rgba(0,0,0,0.05); }
.contact-info { margin: 15px 0 25px; padding-bottom: 15px; border-bottom: 1px solid #eee; }
.contact-info h3 { color: var(--accent); margin-bottom: 6px; }
.contact-form { background: #F2EAE1; padding: 25px; border-radius: 12px; max-width: 800px; margin: 0 auto; }
.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 15px; margin-bottom: 15px; }
.form-group { display: flex; flex-direction: column; gap: 6px; margin-bottom: 15px; }
.form-group label { font-weight: 600; color: var(--primary); font-size: 14px; }
.form-group input, .form-group textarea {
  padding: 10px 14px; border: 1px solid #D5C7B8; border-radius: 6px;
  font-size: 15px; outline: none; font-family: inherit;
}
.form-group input:focus, .form-group textarea:focus { border-color: var(--accent); }
.form-group textarea { min-height: 120px; resize: vertical; }
.btn-submit {
  display: block; width: 160px; margin: 10px auto 0; padding: 11px;
  background: var(--accent); color: #fff; border: none; border-radius: 25px;
  font-size: 15px; font-weight: bold; cursor: pointer; transition: 0.3s;
}
.btn-submit:hover { background: var(--accent-hover); }

/* ================= 7. FOOTER & BẢNG THÀNH VIÊN ================= */
footer { background: var(--primary); color: #fff; padding: 40px 6% 25px; margin-top: 50px; text-align: center; }
.footer-top { display: flex; justify-content: space-around; flex-wrap: wrap; gap: 20px; margin-bottom: 25px; }
.footer-links a { color: #fff; text-decoration: none; margin: 0 10px; }
.footer-links a:hover { text-decoration: underline; }
.footer-copy { font-size: 13px; color: #B8A99A; margin-bottom: 20px; }
.member-table {
  width: 100%; max-width: 500px; margin: 0 auto; border-collapse: collapse;
  background: rgba(255,255,255,0.05); border-radius: 8px; overflow: hidden;
}
.member-table th, .member-table td { padding: 9px 15px; border: 1px solid rgba(255,255,255,0.15); font-size: 14px; text-align: left; }
.member-table th { background: rgba(114, 47, 55, 0.4); }

/* ================= 8. MODAL ĐĂNG NHẬP / ĐĂNG KÝ ================= */
.modal-overlay {
  display: none; position: fixed; inset: 0; background: rgba(23, 43, 77, 0.7);
  justify-content: center; align-items: center; z-index: 1000; padding: 15px;
}
.modal-overlay.active { display: flex; }
.modal-box {
  background: #fff; width: 100%; max-width: 360px; padding: 30px;
  border-radius: 12px; position: relative; box-shadow: 0 10px 25px rgba(0,0,0,0.2);
}
.modal-close { position: absolute; top: 10px; right: 14px; font-size: 24px; background: none; border: none; cursor: pointer; color: var(--primary); }
.modal-box h2 { text-align: center; color: var(--primary); margin-bottom: 20px; }
.modal-box input { width: 100%; padding: 10px 12px; margin-bottom: 12px; border: 1px solid #D5DCE5; border-radius: 6px; outline: none; }
.modal-box input:focus { border-color: var(--primary); }
.modal-box button[type="submit"] {
  width: 100%; padding: 11px; background: var(--primary); color: #fff;
  border: none; border-radius: 6px; font-weight: bold; cursor: pointer; transition: 0.3s;
}
.modal-box button[type="submit"]:hover { background: var(--accent); }
.modal-box p { text-align: center; font-size: 13px; color: var(--text-muted); margin-top: 15px; }
.modal-box a { color: var(--accent); font-weight: bold; text-decoration: none; }

/* ================= 9. RESPONSIVE MOBILE (@media max-width: 768px) ================= */
@media (max-width: 768px) {
  .hamburger { display: flex; }
  .menu {
    display: none; position: absolute; top: 100%; left: 0; width: 100%;
    background: var(--primary); flex-direction: column; padding: 15px 0; z-index: 99;
    margin: 0;
  }
  .menu.open { display: flex; }
  .account-btns { display: none; }
  .mobile-auth { display: flex; flex-direction: column; gap: 8px; width: 80%; margin: 10px auto 0; }
  .mobile-auth a { text-align: center; }
  .form-row, .feature-list { grid-template-columns: 1fr; }
}

@media (min-width: 769px) {
  .mobile-auth { display: none; }
}