/* ===== 校园二手图书交易平台 · 全站统一样式 ===== */
* { margin: 0; padding: 0; box-sizing: border-box; font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif; }
body { background-color: #f4f7f6; color: #333; line-height: 1.6; }
a { text-decoration: none; color: #3498db; }

/* ---------- 顶部导航 ---------- */
header { background-color: #2c3e50; color: #fff; padding: 15px 0; box-shadow: 0 2px 5px rgba(0,0,0,0.1); }
.nav-container { max-width: 1100px; margin: 0 auto; display: flex; justify-content: space-between; align-items: center; padding: 0 20px; }
.logo { font-size: 22px; font-weight: bold; color: #f39c12; }
.nav-links { display: flex; gap: 20px; flex-wrap: wrap; }
.nav-links a { color: #fff; font-weight: 500; transition: color 0.3s; }
.nav-links a:hover { color: #f39c12; }

/* ---------- 页面内容区 ---------- */
.page-wrap { max-width: 1100px; margin: 0 auto; padding: 30px 20px 0; }
.page-title { font-size: 22px; color: #2c3e50; border-left: 4px solid #f39c12; padding-left: 10px; margin-bottom: 20px; }
.page-desc { color: #666; font-size: 14px; text-align: center; margin-bottom: 20px; }

/* ---------- 卡片 ---------- */
.card { background: #fff; border-radius: 8px; box-shadow: 0 2px 10px rgba(0,0,0,0.05); padding: 25px; }
.card-center { max-width: 460px; margin: 20px auto; }
.card-wide { max-width: 900px; margin: 20px auto; }

/* ---------- 表单 ---------- */
.form-row { display: flex; align-items: center; margin-bottom: 15px; }
.form-label { width: 110px; text-align: right; padding-right: 10px; color: #555; flex-shrink: 0; }
.form-input { flex: 1; padding: 10px 12px; border: 1px solid #ddd; border-radius: 4px; font-size: 15px; outline: none; }
.form-input:focus { border-color: #3498db; }
.btn-row { text-align: center; margin-top: 10px; }
.btn { padding: 10px 30px; background-color: #3498db; color: #fff; border: none; border-radius: 4px; cursor: pointer; font-size: 15px; transition: background-color 0.3s; }
.btn:hover { background-color: #2980b9; }
.btn-reset { background-color: #95a5a6; }
.btn-reset:hover { background-color: #7f8c8d; }

/* ---------- 提示与结果 ---------- */
.msg { text-align: center; padding: 20px 0; font-size: 16px; }
.msg-ok { color: #16a085; }
.msg-error { color: #e74c3c; }
.result-links { text-align: center; margin-top: 15px; }
.result-links a { margin: 0 8px; }
.sql-info { text-align: center; color: #7f8c8d; font-size: 12px; word-break: break-all; margin-top: 10px; }

/* ---------- 数据表格 ---------- */
.table-wrap { overflow-x: auto; }
.data-table { width: 100%; border-collapse: collapse; background: #fff; border-radius: 8px; overflow: hidden; box-shadow: 0 2px 10px rgba(0,0,0,0.05); }
.data-table th { background: #2c3e50; color: #fff; padding: 10px 12px; text-align: center; font-weight: 600; }
.data-table td { padding: 9px 12px; border-bottom: 1px solid #ecf0f1; text-align: center; }
.data-table tbody tr:hover { background: #f8f9fa; }

/* ---------- 主页：检索区 ---------- */
.search-section { background: #fff; padding: 30px 20px; text-align: center; box-shadow: 0 2px 10px rgba(0,0,0,0.05); margin-bottom: 30px; }
.search-section h2 { margin-bottom: 20px; color: #2c3e50; }
.search-box { display: flex; justify-content: center; max-width: 600px; margin: 0 auto; }
.search-box input { flex: 1; padding: 12px 15px; border: 1px solid #ddd; border-radius: 4px 0 0 4px; font-size: 16px; outline: none; }
.search-box button { padding: 12px 30px; background-color: #3498db; color: #fff; border: none; border-radius: 0 4px 4px 0; cursor: pointer; font-size: 16px; }
.search-box button:hover { background-color: #2980b9; }

/* ---------- 主页：图书列表 ---------- */
.main-content { max-width: 1100px; margin: 0 auto; padding: 0 20px; }
.section-title { font-size: 22px; margin-bottom: 20px; color: #2c3e50; border-left: 4px solid #f39c12; padding-left: 10px; }
.book-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 20px; }
.book-card { background: #fff; border-radius: 8px; overflow: hidden; box-shadow: 0 2px 10px rgba(0,0,0,0.05); transition: transform 0.3s; }
.book-card:hover { transform: translateY(-5px); }
.book-img { height: 160px; background-color: #ecf0f1; display: flex; align-items: center; justify-content: center; color: #bdc3c7; font-size: 14px; font-weight: bold; }
.book-info { padding: 15px; }
.book-info h3 { font-size: 18px; margin-bottom: 8px; color: #2c3e50; }
.book-info p { color: #666; font-size: 14px; margin-bottom: 5px; }
.book-info .price { color: #e74c3c; font-size: 20px; font-weight: bold; margin: 10px 0; }
.btn-link { display: block; text-align: center; padding: 8px; background-color: #3498db; color: #fff; border-radius: 4px; cursor: pointer; font-size: 14px; margin-top: 10px; }
.btn-link:hover { background-color: #2980b9; color: #fff; }

/* ---------- 关于我们：双人卡片 ---------- */
.about-cards { display: flex; flex-direction: row; flex-wrap: wrap; justify-content: center; gap: 24px; }
.profile-card { background: #fff; border-radius: 16px; box-shadow: 0 8px 24px rgba(0,0,0,0.08); padding: 25px; flex: 1; min-width: 280px; max-width: 520px; display: flex; flex-direction: column; }
.avatar { width: 100px; height: 100px; border-radius: 50%; margin: 0 auto 15px; display: flex; align-items: center; justify-content: center; font-size: 2.5rem; color: #fff; box-shadow: 0 4px 10px rgba(0,0,0,0.1); }
.avatar-1 { background: linear-gradient(45deg, #a1c4fd, #c2e9fb); }
.avatar-2 { background: linear-gradient(45deg, #fbc2eb, #a6c1ee); }
.name { font-size: 1.5rem; color: #2c3e50; margin-bottom: 4px; text-align: center; }
.role { font-size: 0.9rem; color: #7f8c8d; font-weight: 600; margin-bottom: 15px; text-align: center; }
.bio { font-size: 0.9rem; color: #555; line-height: 1.6; text-align: left; margin-bottom: 15px; flex-grow: 1; }
.skills { display: flex; flex-wrap: wrap; gap: 8px; justify-content: center; }
.skill-tag { background-color: #f0f2f5; color: #3498db; padding: 5px 12px; border-radius: 15px; font-size: 0.8rem; font-weight: 600; }

/* ---------- 页脚 ---------- */
footer { text-align: center; padding: 20px; background-color: #2c3e50; color: #bdc3c7; font-size: 14px; margin-top: 40px; }

/* ---------- 移动端适配 ---------- */
@media (max-width: 600px) {
    .nav-container { flex-direction: column; gap: 10px; }
    .nav-links { gap: 12px; justify-content: center; }
    .form-row { flex-direction: column; align-items: stretch; }
    .form-label { width: auto; text-align: left; padding: 0 0 5px; }
    .about-cards { flex-direction: column; }
}