:root {
    --color-bg: #ffffff;
    --color-surface: #fafafa;
    --color-border: #e0e0e0;
    --color-text: #1a1a1a;
    --color-text-secondary: #666666;
    --color-primary: #000000;
    --color-primary-light: #333333;
    --color-completed: #4caf50;
    --color-high: #f44336;
    --color-medium: #ff9800;
    --color-low: #4caf50;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    background-color: var(--color-bg);
    color: var(--color-text);
    line-height: 1.6;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 30px 0;
    border-bottom: 1px solid var(--color-border);
    margin-bottom: 30px;
}

.header-content .title {
    font-size: 28px;
    font-weight: 300;
    letter-spacing: -0.5px;
    margin-bottom: 10px;
}

.header-actions {
    display: flex;
    align-items: center;
    gap: 20px;
}

.auth-btn {
    padding: 8px 16px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    color: var(--color-text);
    cursor: pointer;
    font-size: 13px;
    transition: all 0.2s;
}

.auth-btn:hover {
    border-color: var(--color-primary);
}

.auth-btn.authenticated {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

.project-info {
    display: flex;
    gap: 15px;
}

.info-badge {
    font-size: 13px;
    color: var(--color-text-secondary);
}

.info-badge span {
    color: var(--color-text);
    font-weight: 500;
}

.theme-switcher {
    display: flex;
    gap: 5px;
}

.theme-btn {
    width: 40px;
    height: 40px;
    border: 1px solid var(--color-border);
    background: var(--color-bg);
    color: var(--color-text);
    cursor: pointer;
    font-size: 14px;
    transition: all 0.2s;
}

.theme-btn:hover {
    border-color: var(--color-primary);
}

.theme-btn.active {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

.nav-tabs {
    display: flex;
    gap: 5px;
    border-bottom: 1px solid var(--color-border);
    margin-bottom: 30px;
    overflow-x: auto;
}

.tab-btn {
    padding: 12px 20px;
    border: none;
    background: transparent;
    color: var(--color-text-secondary);
    cursor: pointer;
    font-size: 14px;
    white-space: nowrap;
    border-bottom: 2px solid transparent;
    transition: all 0.2s;
}

.tab-btn:hover {
    color: var(--color-text);
}

.tab-btn.active {
    color: var(--color-primary);
    border-bottom-color: var(--color-primary);
}

.toolbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
    margin-bottom: 30px;
}

.search-box {
    flex: 1;
    max-width: 400px;
    padding: 10px 15px;
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    font-size: 14px;
    outline: none;
    transition: border-color 0.2s;
}

.search-box:focus {
    border-color: var(--color-primary);
}

.toolbar-actions {
    display: flex;
    align-items: center;
    gap: 15px;
}

.action-btn {
    padding: 10px 20px;
    border: 1px solid var(--color-border);
    background: var(--color-bg);
    color: var(--color-text);
    cursor: pointer;
    font-size: 13px;
    transition: all 0.2s;
}

.action-btn:hover {
    border-color: var(--color-primary);
    background: var(--color-primary);
    color: white;
}

.stats {
    font-size: 13px;
    color: var(--color-text-secondary);
}

.task-group {
    margin-bottom: 40px;
}

.group-title {
    font-size: 18px;
    font-weight: 400;
    margin-bottom: 20px;
    padding-bottom: 10px;
    border-bottom: 1px solid var(--color-border);
}

.group-count {
    color: var(--color-text-secondary);
    font-size: 14px;
    font-weight: 300;
}

.tasks-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 20px;
}

.task-card {
    padding: 20px;
    border: 1px solid var(--color-border);
    background: var(--color-bg);
    cursor: pointer;
    transition: all 0.2s;
}

.task-card:hover {
    border-color: var(--color-primary);
}

.task-card.completed {
    opacity: 0.5;
}

.task-card.priority-high {
    border-left: 3px solid var(--color-high);
}

.task-card.priority-medium {
    border-left: 3px solid var(--color-medium);
}

.task-card.priority-low {
    border-left: 3px solid var(--color-low);
}

.task-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 12px;
}

.task-checkbox {
    width: 18px;
    height: 18px;
    cursor: pointer;
}

.task-id {
    font-size: 11px;
    color: var(--color-text-secondary);
    font-family: monospace;
}

.task-priority {
    margin-left: auto;
}

.task-title {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 8px;
    line-height: 1.4;
}

.task-description {
    font-size: 13px;
    color: var(--color-text-secondary);
    margin-bottom: 12px;
    line-height: 1.5;
}

.task-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    font-size: 12px;
    color: var(--color-text-secondary);
}

.meta-item {
    white-space: nowrap;
}

.task-budget,
.task-checklist-preview {
    margin-top: 10px;
    padding-top: 10px;
    border-top: 1px solid var(--color-border);
    font-size: 12px;
    color: var(--color-text-secondary);
}

.empty-state,
.loading,
.error {
    text-align: center;
    padding: 60px 20px;
    color: var(--color-text-secondary);
}

.error {
    color: var(--color-high);
}

.footer {
    margin-top: 60px;
    padding: 30px 0;
    border-top: 1px solid var(--color-border);
    text-align: center;
    font-size: 13px;
    color: var(--color-text-secondary);
}

.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.5);
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.modal-content {
    background: var(--color-bg);
    padding: 40px;
    max-width: 700px;
    max-height: 80vh;
    overflow-y: auto;
    position: relative;
    border: 1px solid var(--color-border);
}

.modal-close {
    position: absolute;
    top: 15px;
    right: 20px;
    font-size: 28px;
    cursor: pointer;
    color: var(--color-text-secondary);
    line-height: 1;
}

.modal-close:hover {
    color: var(--color-text);
}

.detail-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 15px 0 25px;
}

.badge {
    padding: 4px 10px;
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    font-size: 12px;
}

.badge.priority-high {
    background: var(--color-high);
    color: white;
    border-color: var(--color-high);
}

.badge.priority-medium {
    background: var(--color-medium);
    color: white;
    border-color: var(--color-medium);
}

.badge.priority-low {
    background: var(--color-low);
    color: white;
    border-color: var(--color-low);
}

.detail-section {
    margin-bottom: 25px;
}

.detail-section h3 {
    font-size: 16px;
    font-weight: 500;
    margin-bottom: 12px;
}

.detail-section ul {
    list-style: none;
    padding: 0;
}

.detail-section ul li {
    padding: 6px 0;
    font-size: 14px;
}

.detail-section a {
    color: var(--color-primary);
    text-decoration: none;
}

.detail-section a:hover {
    text-decoration: underline;
}

.checklist li {
    display: flex;
    align-items: center;
    gap: 10px;
}

/* 表单样式 */
.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 500;
    margin-bottom: 6px;
    color: var(--color-text);
}

.form-group input,
.form-group textarea,
.form-group select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid var(--color-border);
    background: var(--color-surface);
    font-size: 14px;
    outline: none;
    transition: border-color 0.2s;
}

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

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
}

.form-actions {
    display: flex;
    gap: 10px;
    margin-top: 25px;
    padding-top: 20px;
    border-top: 1px solid var(--color-border);
}

.btn-primary,
.btn-secondary,
.btn-danger {
    padding: 10px 20px;
    border: 1px solid;
    cursor: pointer;
    font-size: 13px;
    transition: all 0.2s;
}

.btn-primary {
    background: var(--color-primary);
    color: white;
    border-color: var(--color-primary);
}

.btn-primary:hover {
    opacity: 0.85;
}

.btn-secondary {
    background: var(--color-surface);
    color: var(--color-text);
    border-color: var(--color-border);
}

.btn-secondary:hover {
    border-color: var(--color-primary);
}

.btn-danger {
    background: var(--color-high);
    color: white;
    border-color: var(--color-high);
}

.btn-danger:hover {
    opacity: 0.85;
}

/* 编辑按钮 */
.edit-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 14px;
    padding: 2px 6px;
    margin-left: auto;
    opacity: 0.6;
    transition: opacity 0.2s;
}

.edit-btn:hover {
    opacity: 1;
}

.task-card:hover .edit-btn {
    opacity: 1;
}

.detail-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 15px;
}

.detail-header h2 {
    margin: 0;
}

.edit-btn-large {
    padding: 8px 16px;
    background: var(--color-primary);
    color: white;
    border: none;
    cursor: pointer;
    font-size: 13px;
}

.edit-btn-large:hover {
    opacity: 0.9;
}

@media (max-width: 768px) {
    .header {
        flex-direction: column;
        align-items: flex-start;
        gap: 20px;
    }
    
    .toolbar {
        flex-direction: column;
        align-items: stretch;
    }
    
    .search-box {
        max-width: 100%;
    }
    
    .tasks-grid {
        grid-template-columns: 1fr;
    }
    
    .modal-content {
        padding: 30px 20px;
        max-width: 95%;
    }

    .form-row {
        grid-template-columns: 1fr;
    }

    .form-actions {
        flex-direction: column;
    }
}