/* =============================================
   校园二手交易平台 — 蓝白主题样式
   ============================================= */

:root {
    --primary: #1a5276;
    --primary-light: #2980b9;
    --primary-lighter: #d4e6f1;
    --primary-bg: #eaf2f8;
    --bg: #f0f3f7;
    --sidebar-bg: #1a5276;
    --card-bg: #ffffff;
    --text: #2c3e50;
    --text-muted: #7f8c8d;
    --border: #dce1e6;
    --danger: #c0392b;
    --success: #27ae60;
    --warning: #e67e22;
    --radius: 4px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
                 "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica,
                 Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    font-size: 14px;
    line-height: 1.6;
}

/* ---- Layout ---- */
.layout {
    display: flex;
    min-height: 100vh;
}

/* ---- Sidebar ---- */
.sidebar {
    width: 240px;
    background: var(--sidebar-bg);
    color: #ecf0f1;
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    position: fixed;
    top: 0;
    left: 0;
    height: 100vh;
    z-index: 100;
}

.sidebar-header {
    padding: 24px 20px 16px;
    border-bottom: 1px solid rgba(255,255,255,0.1);
}

.sidebar-header h1 {
    font-size: 16px;
    font-weight: 600;
    letter-spacing: 1px;
}

.sidebar-header .subtitle {
    font-size: 11px;
    color: rgba(255,255,255,0.5);
    margin-top: 4px;
}

.sidebar-nav {
    flex: 1;
    padding: 12px 0;
}

.nav-item {
    display: block;
    padding: 10px 20px;
    color: rgba(255,255,255,0.75);
    text-decoration: none;
    font-size: 14px;
    transition: background 0.15s, color 0.15s;
    border-left: 3px solid transparent;
}

.nav-item:hover {
    background: rgba(255,255,255,0.08);
    color: #fff;
}

.nav-item.active {
    background: rgba(255,255,255,0.12);
    color: #fff;
    border-left-color: #3498db;
}

.nav-icon {
    margin-right: 8px;
    font-size: 10px;
    opacity: 0.6;
}

.purchase-link {
    margin-top: 8px;
    border-top: 1px solid rgba(255,255,255,0.1);
    padding-top: 12px;
    color: #f1c40f;
}

.sidebar-footer {
    padding: 16px 20px;
    border-top: 1px solid rgba(255,255,255,0.1);
    font-size: 11px;
    color: rgba(255,255,255,0.4);
}

/* ---- Main Content ---- */
.main-content {
    flex: 1;
    margin-left: 240px;
    min-width: 0;
}

.top-bar {
    background: var(--card-bg);
    padding: 16px 28px;
    border-bottom: 1px solid var(--border);
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}

.page-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--primary);
}

.content-area {
    padding: 24px 28px;
}

/* ---- Flash Messages ---- */
.flash-messages {
    padding: 0 28px;
    margin-top: 12px;
}

.flash-msg {
    padding: 10px 16px;
    border-radius: var(--radius);
    margin-bottom: 8px;
    font-size: 13px;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.flash-success {
    background: #d4efdf;
    color: #1e8449;
    border: 1px solid #a9dfbf;
}

.flash-error {
    background: #fadbd8;
    color: #922b21;
    border: 1px solid #f5b7b1;
}

.flash-close {
    cursor: pointer;
    font-size: 16px;
    opacity: 0.5;
    margin-left: 12px;
}

.flash-close:hover {
    opacity: 1;
}

/* ---- Stats Cards ---- */
.stats-cards {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.stat-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    text-align: center;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
    border-top: 3px solid var(--primary-light);
}

.stat-number {
    font-size: 28px;
    font-weight: 700;
    color: var(--primary);
}

.stat-label {
    font-size: 12px;
    color: var(--text-muted);
    margin-top: 4px;
}

/* ---- Quick Nav ---- */
.quick-nav {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 24px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.quick-nav h3 {
    font-size: 15px;
    margin-bottom: 12px;
    color: var(--primary);
}

.nav-grid {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.quick-btn {
    display: inline-block;
    padding: 10px 24px;
    background: var(--primary-lighter);
    color: var(--primary);
    text-decoration: none;
    border-radius: var(--radius);
    font-size: 13px;
    font-weight: 500;
    transition: background 0.15s;
}

.quick-btn:hover {
    background: #aed6f1;
}

.quick-btn.highlight {
    background: var(--primary);
    color: #fff;
}

.quick-btn.highlight:hover {
    background: var(--primary-light);
}

/* ---- Charts ---- */
.charts-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
    margin-bottom: 24px;
}

.chart-box {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.chart-box h3 {
    font-size: 15px;
    color: var(--primary);
    margin-bottom: 12px;
}

/* ---- Filter Bar ---- */
.filter-bar {
    background: var(--card-bg);
    padding: 16px 20px;
    border-radius: var(--radius);
    margin-bottom: 16px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.filter-form {
    display: flex;
    gap: 10px;
    align-items: center;
    flex-wrap: wrap;
}

.filter-form input,
.filter-form select {
    padding: 7px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 13px;
    outline: none;
}

.filter-form input:focus,
.filter-form select:focus {
    border-color: var(--primary-light);
}

/* ---- Query Buttons ---- */
.query-buttons {
    background: var(--card-bg);
    padding: 14px 20px;
    border-radius: var(--radius);
    margin-bottom: 16px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
    display: flex;
    gap: 8px;
    align-items: center;
    flex-wrap: wrap;
}

.query-label {
    font-size: 12px;
    color: var(--text-muted);
    font-weight: 500;
}

.query-divider {
    width: 1px;
    height: 20px;
    background: var(--border);
    margin: 0 4px;
}

/* ---- Buttons ---- */
.btn {
    display: inline-block;
    padding: 7px 16px;
    font-size: 13px;
    border: none;
    border-radius: var(--radius);
    cursor: pointer;
    text-decoration: none;
    transition: background 0.15s;
    line-height: 1.5;
}

.btn-primary {
    background: var(--primary-light);
    color: #fff;
}

.btn-primary:hover {
    background: var(--primary);
}

.btn-secondary {
    background: #ecf0f1;
    color: var(--text);
}

.btn-secondary:hover {
    background: #d5dbdb;
}

.btn-danger {
    background: var(--danger);
    color: #fff;
}

.btn-danger:hover {
    background: #a93226;
}

.btn-sm {
    padding: 4px 10px;
    font-size: 12px;
}

.btn-accent {
    background: #d4e6f1;
    color: var(--primary);
}

.btn-accent:hover {
    background: #aed6f1;
}

.btn-green {
    background: #d5f5e3;
    color: #1e8449;
}

.btn-green:hover {
    background: #abebc6;
}

/* ---- Stats Result ---- */
.stats-result {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 16px 20px;
    margin-bottom: 16px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
    border-left: 4px solid var(--primary-light);
}

.stats-result h4 {
    font-size: 14px;
    color: var(--primary);
    margin-bottom: 8px;
}

.stat-value {
    font-size: 14px;
}

.stat-value strong {
    font-size: 18px;
    color: var(--primary);
}

/* ---- Query Result Header ---- */
.query-result-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 12px;
    padding: 0 4px;
}

.query-result-header h3 {
    font-size: 15px;
    color: var(--primary);
}

.result-count {
    font-size: 12px;
    color: var(--text-muted);
}

/* ---- Data Table ---- */
.table-container {
    background: var(--card-bg);
    border-radius: var(--radius);
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
    overflow-x: auto;
    margin-bottom: 20px;
}

.data-table {
    width: 100%;
    border-collapse: collapse;
}

.data-table th {
    background: #f8f9fa;
    padding: 10px 14px;
    text-align: left;
    font-size: 12px;
    font-weight: 600;
    color: var(--text-muted);
    text-transform: uppercase;
    border-bottom: 2px solid var(--border);
    white-space: nowrap;
}

.data-table td {
    padding: 10px 14px;
    border-bottom: 1px solid #f0f0f0;
    font-size: 13px;
}

.data-table tbody tr:hover {
    background: #fafbfc;
}

.data-table.compact td {
    padding: 6px 12px;
    font-size: 12px;
}

.price {
    font-family: "SF Mono", "Consolas", monospace;
    font-weight: 500;
}

.empty-text {
    text-align: center;
    color: var(--text-muted);
    padding: 24px !important;
}

/* ---- Tags & Badges ---- */
.tag {
    display: inline-block;
    padding: 2px 8px;
    background: var(--primary-lighter);
    color: var(--primary);
    border-radius: 3px;
    font-size: 12px;
}

.status-badge {
    display: inline-block;
    padding: 2px 10px;
    border-radius: 3px;
    font-size: 12px;
    font-weight: 500;
}

.status-unsold {
    background: #d4efdf;
    color: #1e8449;
}

.status-sold {
    background: #fadbd8;
    color: #922b21;
}

/* ---- Actions Column ---- */
.actions {
    white-space: nowrap;
}

.actions form {
    display: inline;
}

/* ---- Detail Page ---- */
.detail-header {
    margin-bottom: 16px;
}

.detail-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px 24px;
    margin-bottom: 24px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.detail-card h3 {
    font-size: 18px;
    color: var(--primary);
    margin-bottom: 12px;
}

.detail-info p {
    margin-bottom: 6px;
    font-size: 14px;
}

.section-title {
    font-size: 15px;
    font-weight: 600;
    color: var(--primary);
    margin-bottom: 12px;
    padding-left: 4px;
}

/* ---- Form Section ---- */
.form-section {
    margin-top: 24px;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 20px;
}

.form-card {
    background: var(--card-bg);
    border-radius: var(--radius);
    padding: 20px 24px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.06);
}

.form-card h3 {
    font-size: 15px;
    color: var(--primary);
    margin-bottom: 16px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--border);
}

.form-hint {
    font-size: 12px;
    color: var(--text-muted);
    margin-bottom: 16px;
}

.form-group {
    margin-bottom: 14px;
}

.form-group label {
    display: block;
    font-size: 12px;
    font-weight: 500;
    color: var(--text-muted);
    margin-bottom: 4px;
}

.form-group input,
.form-group select {
    width: 100%;
    padding: 8px 12px;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 13px;
    outline: none;
    transition: border-color 0.15s;
}

.form-group input:focus,
.form-group select:focus {
    border-color: var(--primary-light);
}

/* ---- Action Bar ---- */
.action-bar {
    margin-bottom: 16px;
}

/* ---- Responsive ---- */
@media (max-width: 900px) {
    .sidebar {
        width: 200px;
    }
    .main-content {
        margin-left: 200px;
    }
    .form-row {
        grid-template-columns: 1fr;
    }
    .charts-row {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 600px) {
    .sidebar {
        display: none;
    }
    .main-content {
        margin-left: 0;
    }
}