/* ==================== CSS 變數定義 (主題顏色) ==================== */
 :root[data-theme="light"] {
     --bg-color: #f4f6f9;
     --card-bg: #ffffff;
     --text-main: #1e293b;
     --text-muted: #64748b;
     --accent-color: #2563eb;
     --accent-hover: #1d4ed8;
     --border-color: #e2e8f0;
     --shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.05);
     --card-shadow-hover: 0 10px 25px -5px rgba(0, 0, 0, 0.1);
     --toggle-bg: #e2e8f0;
     --toggle-icon: #f59e0b;
 }

 :root[data-theme="dark"] {
     --bg-color: #0f172a;
     --card-bg: #1e293b;
     --text-main: #f8fafc;
     --text-muted: #94a3b8;
     --accent-color: #3b82f6;
     --accent-hover: #60a5fa;
     --border-color: #334155;
     --shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.3);
     --card-shadow-hover: 0 10px 25px -5px rgba(0, 0, 0, 0.5);
     --toggle-bg: #334155;
     --toggle-icon: #f1c40f;
 }

 /* 全局基礎樣式 */
 * {
     box-sizing: border-box;
     margin: 0;
     padding: 0;
     transition: background-color 0.3s ease, color 0.3s ease, border-color 0.3s ease, box-shadow 0.3s ease;
 }

 body {
     font-family: 'Inter', system-ui, -apple-system, sans-serif;
     background-color: var(--bg-color);
     color: var(--text-main);
     min-height: 100vh;
     padding: 0;
 }

 .container {
     width: 100%;
     max-width: 1200px;
     padding: 20px;
     margin: 0 auto;
     display: flex;
     flex-direction: column;
     gap: 24px;
 }

 /* ==================== 頂部頁首 (Header) ==================== */
 header {
     background-color: var(--card-bg);
     border: 1px solid var(--border-color);
     border-radius: 16px;
     padding: 20px 28px;
     display: flex;
     justify-content: space-between;
     align-items: center;
     box-shadow: var(--shadow);
     flex-wrap: wrap;
     gap: 16px;
 }

 .header-title h1 {
     font-size: 1.5rem;
     font-weight: 700;
     color: var(--text-main);
 }

 .auto-refresh-indicator {
     font-size: 0.8rem;
     color: var(--text-muted);
     margin-top: 4px;
     display: flex;
     align-items: center;
     gap: 6px;
 }

 .header-right {
     display: flex;
     align-items: center;
     gap: 16px;
 }

 .clock-container {
     text-align: right;
 }

 .date-display {
     font-size: 0.875rem;
     color: var(--text-muted);
     font-weight: 500;
 }

 .time-display {
     font-size: 1.5rem;
     font-weight: 700;
     font-variant-numeric: tabular-nums;
     color: var(--accent-color);
 }

 /* 功能按鈕區 */
 .btn-group {
     display: flex;
     gap: 10px;
 }

 .icon-btn {
     background-color: var(--toggle-bg);
     border: none;
     width: 44px;
     height: 44px;
     border-radius: 50%;
     cursor: pointer;
     display: flex;
     align-items: center;
     justify-content: center;
     font-size: 1.1rem;
     color: var(--text-main);
 }

 .icon-btn:hover {
     transform: scale(1.05);
 }

 #theme-toggle {
     color: var(--toggle-icon);
 }

 .spin-icon {
     animation: spin 1s linear infinite;
 }

 @keyframes spin {
     100% {
         transform: rotate(360deg);
     }
 }

 /* ==================== 區塊共用標題 ==================== */
 .section-header {
     display: flex;
     justify-content: space-between;
     align-items: center;
     margin-bottom: 16px;
 }

 .section-title {
     font-size: 1.25rem;
     font-weight: 600;
     display: flex;
     align-items: center;
     gap: 10px;
 }

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

 .update-time {
     font-size: 0.8rem;
     color: var(--text-muted);
 }

 /* ==================== 香港天氣區塊 ==================== */
 .weather-section {
     display: flex;
     flex-direction: column;
     gap: 16px;
 }

 .current-weather-card {
     background: linear-gradient(135deg, var(--accent-color), #1d4ed8);
     color: #ffffff;
     border-radius: 16px;
     padding: 24px;
     display: flex;
     justify-content: space-between;
     align-items: center;
     box-shadow: var(--shadow);
     flex-wrap: wrap;
     gap: 20px;
 }

 .weather-main-info {
     display: flex;
     align-items: center;
     gap: 20px;
 }

 .temp-display {
     font-size: 3.5rem;
     font-weight: 700;
     line-height: 1;
 }

 .weather-desc-group {
     display: flex;
     flex-direction: column;
     gap: 4px;
 }

 .weather-location {
     font-size: 1.1rem;
     font-weight: 600;
     opacity: 0.9;
 }

 .weather-desc {
     font-size: 0.95rem;
     opacity: 0.8;
 }

 .weather-extra-info {
     display: flex;
     gap: 24px;
     background: rgba(255, 255, 255, 0.15);
     backdrop-filter: blur(8px);
     padding: 12px 20px;
     border-radius: 12px;
 }

 .extra-item {
     display: flex;
     flex-direction: column;
     align-items: center;
 }

 .extra-item .label {
     font-size: 0.75rem;
     opacity: 0.8;
 }

 .extra-item .value {
     font-size: 1.1rem;
     font-weight: 600;
 }

 /* 一週天氣卡片網格 */
 .forecast-grid {
     display: grid;
     grid-template-columns: repeat(auto-fit, minmax(130px, 1fr));
     gap: 12px;
 }

 .forecast-card {
     background-color: var(--card-bg);
     border: 1px solid var(--border-color);
     border-radius: 12px;
     padding: 16px;
     text-align: center;
     display: flex;
     flex-direction: column;
     align-items: center;
     gap: 8px;
     box-shadow: var(--shadow);
 }

 .forecast-card:hover {
     transform: translateY(-2px);
     box-shadow: var(--card-shadow-hover);
 }

 .forecast-date {
     font-size: 0.85rem;
     font-weight: 600;
 }

 .forecast-week {
     font-size: 0.75rem;
     color: var(--text-muted);
 }

 .forecast-icon {
     font-size: 1.8rem;
     margin: 6px 0;
     color: var(--accent-color);
 }

 .forecast-temp {
     font-size: 0.9rem;
     font-weight: 600;
 }

 .forecast-rh {
     font-size: 0.75rem;
     color: var(--text-muted);
 }

 /* ==================== 空氣質素健康指數 (AQHI) 區塊 ==================== */
 .aqhi-grid {
     display: grid;
     grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
     gap: 16px;
 }

 .aqhi-card {
     background-color: var(--card-bg);
     border: 1px solid var(--border-color);
     border-radius: 16px;
     padding: 20px;
     box-shadow: var(--shadow);
     display: flex;
     flex-direction: column;
     gap: 12px;
 }

 .aqhi-header {
     display: flex;
     justify-content: space-between;
     align-items: center;
 }

 .aqhi-type {
     font-size: 1rem;
     font-weight: 600;
 }

 .aqhi-badge {
     display: flex;
     align-items: center;
     gap: 10px;
 }

 .aqhi-level-box {
     width: 42px;
     height: 42px;
     border-radius: 10px;
     display: flex;
     align-items: center;
     justify-content: center;
     font-size: 1.25rem;
     font-weight: 700;
     color: #ffffff;
 }

 .aqhi-risk {
     font-weight: 700;
     font-size: 1.1rem;
 }

 .aqhi-advice {
     font-size: 0.85rem;
     color: var(--text-muted);
     line-height: 1.4;
 }

 /* AQHI 風險等級顏色設定 */
 .aqhi-low {
     background-color: #00b050;
 }

 .aqhi-moderate {
     background-color: #ffc000;
     color: #000 !important;
 }

 .aqhi-high {
     background-color: #e76d00;
 }

 .aqhi-very-high {
     background-color: #c00000;
 }

 .aqhi-serious {
     background-color: #7030a0;
 }

 /* ==================== 外匯資訊區塊 ==================== */
 .forex-grid {
     display: grid;
     grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
     gap: 16px;
 }

 .forex-card {
     background-color: var(--card-bg);
     border: 1px solid var(--border-color);
     border-radius: 16px;
     padding: 20px;
     display: flex;
     justify-content: space-between;
     align-items: center;
     box-shadow: var(--shadow);
 }

 .forex-card:hover {
     transform: translateY(-2px);
     box-shadow: var(--card-shadow-hover);
 }

 .forex-info {
     display: flex;
     align-items: center;
     gap: 14px;
 }

 .currency-flag {
     width: 44px;
     height: 44px;
     border-radius: 50%;
     background-color: var(--toggle-bg);
     display: flex;
     align-items: center;
     justify-content: center;
     font-weight: 700;
     font-size: 0.85rem;
     color: var(--accent-color);
 }

 .currency-name {
     font-weight: 600;
     font-size: 1rem;
 }

 .currency-code {
     font-size: 0.8rem;
     color: var(--text-muted);
 }

 .forex-rate-group {
     text-align: right;
 }

 .forex-rate {
     font-size: 1.3rem;
     font-weight: 700;
     font-variant-numeric: tabular-nums;
 }

 .forex-unit {
     font-size: 0.75rem;
     color: var(--text-muted);
 }

 /* 響應式微調 */
 @media (max-width: 600px) {
     header {
         flex-direction: column;
         align-items: flex-start;
     }

     .header-right {
         width: 100%;
         justify-content: space-between;
     }

     .current-weather-card {
         flex-direction: column;
         align-items: flex-start;
     }

     .weather-extra-info {
         width: 100%;
         justify-content: space-around;
     }
 }