:root {
    --bg-body: #0f172a;
    --bg-card: #1e293b;
    --bg-input: #0f172a;
    --bg-secondary: #1e293b;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --text-label: #cbd5e1;
    --border-color: #334155;
    --border-input: #475569;
    --accent-color: #38bdf8;
    --accent-hover: #0ea5e9;
    --shadow: 0 1px 3px rgba(0,0,0,0.3);
    --grid-color: #334155;
    --chart-bar: rgba(56, 189, 248, 0.8);
    --chart-bar-border: rgba(56, 189, 248, 1);
    --chart-text: #ffffff;
}

[data-theme="light"] {
    --bg-body: #f5f7fa;
    --bg-card: #ffffff;
    --bg-input: #ffffff;
    --bg-secondary: #f8fafc;
    --text-primary: #1a1a2e;
    --text-secondary: #666666;
    --text-label: #555555;
    --border-color: #e8ecf1;
    --border-input: #d0d7de;
    --accent-color: #0066cc;
    --accent-hover: #0052a3;
    --shadow: 0 1px 3px rgba(0,0,0,0.04);
    --grid-color: #e8ecf1;
    --chart-bar: rgba(0, 102, 204, 0.8);
    --chart-bar-border: rgba(0, 102, 204, 1);
    --chart-text: #666666;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: var(--bg-body);
    min-height: 100vh;
    padding: 20px;
    color: var(--text-primary);
    transition: background 0.3s, color 0.3s;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
}

.header {
    text-align: center;
    margin-bottom: 30px;
    position: relative;
}

.back-link {
    position: absolute;
    left: 0;
    top: 0;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    font-size: 0.85rem;
    color: var(--text-secondary);
    text-decoration: none;
    padding: 8px 16px;
    background: var(--bg-card);
    border-radius: 8px;
    border: 1px solid var(--border-color);
    font-weight: 500;
    transition: all 0.2s ease;
}

.back-link:hover {
    color: var(--accent-color);
    border-color: var(--accent-color);
    background: rgba(56,189,248,0.1);
}

.header h1 {
    font-size: 2rem;
    color: var(--text-primary);
    margin-bottom: 10px;
    font-weight: 700;
}

.header h1 i {
    color: var(--accent-color);
    margin-right: 10px;
}

.header p {
    color: var(--text-secondary);
    font-size: 1rem;
}

.theme-toggle {
    position: absolute;
    right: 0;
    top: 0;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 50%;
    width: 36px;
    height: 36px;
    padding: 0;
    color: var(--text-secondary);
    cursor: pointer;
    font-size: 1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.theme-toggle:hover {
    border-color: var(--accent-color);
    color: var(--accent-color);
}

[data-theme="light"] .theme-toggle {
    color: #fbbf24;
}

[data-theme="light"] .theme-toggle:hover {
    border-color: #fbbf24;
    color: #f59e0b;
}

.tool-nav {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-top: 10px;
    flex-wrap: wrap;
}

.tool-nav a {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    background: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: 20px;
    color: var(--text-secondary);
    text-decoration: none;
    font-size: 0.85rem;
    font-weight: 500;
    transition: all 0.2s;
}

.tool-nav a:hover {
    color: var(--accent-color);
    border-color: var(--accent-color);
    background: rgba(56,189,248,0.1);
}

.tool-nav a.active {
    background: var(--accent-color);
    color: #fff;
    border-color: var(--accent-color);
}

.main-grid {
    display: grid;
    grid-template-columns: 350px 1fr;
    gap: 20px;
}

.card {
    background: var(--bg-card);
    border-radius: 12px;
    padding: 24px;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow);
    transition: background 0.3s, border-color 0.3s;
}

.card-title {
    font-size: 1.1rem;
    margin-bottom: 20px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
}

.card-title i {
    color: var(--accent-color);
}

.form-group {
    margin-bottom: 18px;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    color: var(--text-label);
    font-size: 0.875rem;
    font-weight: 500;
}

.form-group input[type="number"] {
    width: 100%;
    padding: 10px 14px;
    border: 1px solid var(--border-input);
    border-radius: 8px;
    background: var(--bg-input);
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: all 0.2s;
}

.form-group input[type="number"]:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(0,102,204,0.1);
}

.form-group select {
    width: 100%;
    padding: 10px 36px 10px 14px;
    border: 1px solid var(--border-input);
    border-radius: 8px;
    background: var(--bg-input);
    color: var(--text-primary);
    font-size: 0.95rem;
    transition: all 0.2s;
    appearance: none;
    -webkit-appearance: none;
    -moz-appearance: none;
    cursor: pointer;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%2394a3b8' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 12px center;
}

[data-theme="light"] .form-group select {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23666' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
}

.form-group select:focus {
    outline: none;
    border-color: var(--accent-color);
    box-shadow: 0 0 0 3px rgba(0,102,204,0.1);
}

.form-group select option {
    background: var(--bg-card);
    color: var(--text-primary);
    padding: 8px;
}

.form-text {
    display: block;
    margin-top: 4px;
    font-size: 0.8rem;
    color: var(--text-secondary);
}

.input-with-slider {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.input-with-slider input[type="range"] {
    width: 100%;
    height: 4px;
    -webkit-appearance: none;
    appearance: none;
    background: var(--grid-color);
    border-radius: 2px;
    outline: none;
}

.input-with-slider input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 16px;
    height: 16px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
    box-shadow: 0 2px 4px rgba(24,144,255,0.3);
}

.input-with-slider input[type="range"]::-moz-range-thumb {
    width: 16px;
    height: 16px;
    background: var(--accent-color);
    border-radius: 50%;
    cursor: pointer;
    border: none;
    box-shadow: 0 2px 4px rgba(24,144,255,0.3);
}

.btn-calculate {
    width: 100%;
    padding: 12px;
    background: var(--accent-color);
    border: none;
    border-radius: 8px;
    color: #fff;
    font-size: 1rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

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

/* 城市信息卡片 */
.city-info-card {
    padding: 0;
}

.city-info-card.hidden {
    display: none;
}

.info-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 10px;
}

.info-item {
    display: flex;
    flex-direction: column;
}

.info-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 2px;
}

.info-value {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-primary);
}

/* 计算说明 */
.notes-content {
    color: var(--text-secondary);
    font-size: 0.85rem;
    line-height: 1.7;
}

.notes-content ul {
    list-style: none;
    padding: 0;
    margin: 0;
}

.notes-content li {
    position: relative;
    padding-left: 18px;
    margin-bottom: 8px;
}

.notes-content li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--accent-color);
}

.notes-content li:last-child {
    margin-bottom: 0;
}

/* 本次计算参数 - 单行内联样式 */
.calc-params-inline {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    padding: 10px 16px;
    margin-bottom: 20px;
    background: var(--bg-secondary);
    border-radius: 6px;
    border: 1px solid var(--border-color);
    font-size: 0.85rem;
    color: var(--text-secondary);
}

.param-inline-item {
    display: flex;
    align-items: center;
    gap: 4px;
}

.param-inline-item i {
    color: var(--text-secondary);
    font-size: 0.8rem;
}

.param-inline-item:first-child i {
    color: var(--accent-color);
}

/* 统计卡片 - 横向布局 */
.summary-cards {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 12px;
    margin-bottom: 20px;
}

@media (max-width: 900px) {
    .summary-cards {
        grid-template-columns: repeat(2, 1fr);
    }
}

.summary-card {
    background: var(--bg-secondary);
    border-radius: 10px;
    padding: 16px;
    border: 1px solid var(--border-color);
    display: flex;
    align-items: center;
    gap: 12px;
    transition: background 0.3s, border-color 0.3s;
}

.card-icon {
    width: 44px;
    height: 44px;
    border-radius: 10px;
    background: rgba(56, 189, 248, 0.15);
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.card-icon i {
    font-size: 1.2rem;
    color: var(--accent-color);
}

.card-content {
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.card-label {
    font-size: 0.8rem;
    color: var(--text-secondary);
    margin-bottom: 2px;
}

.card-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--accent-color);
}

/* 图表容器 */
.chart-container {
    position: relative;
    height: 320px;
    margin-top: 16px;
}

/* 表格 */
.data-table {
    width: 100%;
    border-collapse: collapse;
    margin-top: 16px;
    font-size: 0.9rem;
}

.data-table th,
.data-table td {
    padding: 10px 12px;
    text-align: left;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-primary);
}

.data-table th {
    color: var(--text-primary);
    font-weight: 600;
    background: var(--bg-secondary);
}

.data-table tbody tr:hover {
    background: var(--bg-secondary);
}

/* 页脚 */
.footer {
    text-align: center;
    padding: 20px;
    color: var(--text-secondary);
    font-size: 0.85rem;
}

.footer p {
    margin-bottom: 4px;
}

/* 错误提示 */
.error-message {
    background: rgba(207, 19, 34, 0.1);
    border: 1px solid rgba(207, 19, 34, 0.3);
    color: #ff4d4f;
    padding: 12px 16px;
    border-radius: 8px;
    margin-bottom: 16px;
    font-size: 0.9rem;
}

/* 加载状态 */
.loading {
    display: inline-block;
    width: 16px;
    height: 16px;
    border: 2px solid var(--grid-color);
    border-top-color: var(--accent-color);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to {
        transform: rotate(360deg);
    }
}

/* 响应式优化 */
@media (max-width: 900px) {
    .main-grid {
        grid-template-columns: 1fr;
    }
    .result-grid {
        grid-template-columns: 1fr;
    }
    .theme-toggle {
        position: static;
        margin: 0 auto 16px;
        width: fit-content;
    }
}