/* BookTracker 后台样式 */
.book-edit-link {
    color: #467b96;
    text-decoration: none;
    margin-right: 8px;
}
.book-edit-link:hover {
    color: #e47e00;
}
.single-delete-btn {
    color: #c33;
    text-decoration: none;
}
.single-delete-btn:hover {
    color: #f00;
}

/* 前端图表容器 */
.book-chart {
    width: 100%;
    min-height: 400px;
    margin: 20px 0;
    border: 1px solid #eee;
    border-radius: 8px;
    background: #fff;
}

/* 图表加载状态 */
.book-chart-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 400px;
    color: #999;
    font-size: 14px;
}

/* 图表错误状态 */
.book-chart-error {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 200px;
    color: #c33;
    font-size: 14px;
}

/* 图表外层容器 */
.chart-wrapper {
    width: 100%;
    min-height: inherit;
}

/* 时间段导航栏 */
.chart-period-nav {
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 12px 0 8px;
    gap: 16px;
    user-select: none;
}

.chart-period-nav .nav-btn {
    background: #f5f5f5;
    border: 1px solid #ddd;
    border-radius: 6px;
    width: 34px;
    height: 34px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 20px;
    color: #666;
    line-height: 1;
    transition: background 0.2s, color 0.2s, border-color 0.2s;
}

.chart-period-nav .nav-btn:hover:not(:disabled) {
    background: #5470c6;
    color: #fff;
    border-color: #5470c6;
}

.chart-period-nav .nav-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

.chart-period-nav .nav-label {
    font-size: 16px;
    font-weight: 600;
    color: #333;
    min-width: 120px;
    text-align: center;
}

/* 图表主体 */
.chart-body {
    padding: 0 10px 10px;
}