/* -------------------------------------------------------------
 * 全域變數與重設 (CSS Variables & Reset)
 * ------------------------------------------------------------- */
:root {
    /* 現代暗黑漸層色調 */
    --bg-primary: #0f172a;       /* 深邃藍底色 */
    --bg-secondary: #1e293b;     /* 卡片深灰藍底色 */
    --bg-tertiary: #334155;      /* 懸停與邊框色 */
    
    --text-primary: #f8fafc;     /* 主文字顏色 (亮白) */
    --text-secondary: #94a3b8;   /* 次文字顏色 (灰白) */
    --text-muted: #64748b;       /* 暗淡文字顏色 */
    
    /* 點綴色 (亮麗漸層) */
    --accent-blue: #38bdf8;      /* 天空藍 */
    --accent-purple: #c084fc;    /* 粉紫色 */
    --accent-green: #34d399;     /* 翡翠綠 */
    --accent-red: #f87171;       /* 珊瑚紅 */
    
    --border-color: #334155;     /* 邊框顏色 */
    --border-hover: #475569;     /* 邊框懸停色 */
    
    --font-sans: 'Outfit', 'Noto Sans TC', sans-serif;
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --border-radius-lg: 16px;
    --border-radius-md: 10px;
    --shadow-lg: 0 10px 25px -5px rgba(0, 0, 0, 0.3), 0 8px 10px -6px rgba(0, 0, 0, 0.3);
    --shadow-highlight: 0 0 20px rgba(56, 189, 248, 0.15);
}

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

body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: var(--font-sans);
    min-height: 100vh;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    padding: 2rem 1rem;
    overflow-x: hidden;
}

/* -------------------------------------------------------------
 * 應用程式容器版面 (Layout Container)
 * ------------------------------------------------------------- */
.app-container {
    width: 100%;
    max-width: 1100px;
    display: flex;
    flex-direction: column;
    gap: 2rem;
}

/* 頂部標題區 */
.app-header {
    text-align: center;
    padding: 1.5rem 0;
}

.main-title {
    font-size: 3rem;
    font-weight: 800;
    letter-spacing: -0.05em;
    margin-bottom: 0.5rem;
    background: linear-gradient(135deg, var(--accent-blue), var(--accent-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.main-title span {
    font-weight: 300;
    color: var(--text-primary);
    -webkit-text-fill-color: var(--text-primary);
}

.sub-title {
    color: var(--text-secondary);
    font-size: 1.1rem;
    font-weight: 300;
}

/* 主要區塊 */
.main-content {
    display: flex;
    flex-direction: column;
    gap: 2rem;
    width: 100%;
}

/* -------------------------------------------------------------
 * 拖放上傳區樣式 (Drop Zone & Upload Section)
 * ------------------------------------------------------------- */
.upload-section {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 255, 255, 0.05);
    transition: var(--transition-smooth);
}

.drop-zone {
    border: 2px dashed var(--border-color);
    border-radius: var(--border-radius-md);
    padding: 3rem 2rem;
    text-align: center;
    cursor: pointer;
    background: rgba(30, 41, 59, 0.4);
    transition: var(--transition-smooth);
    position: relative;
    overflow: hidden;
}

/* 拖曳檔案在上方的特效 */
.drop-zone.dragover {
    border-color: var(--accent-blue);
    background: rgba(56, 189, 248, 0.08);
    box-shadow: var(--shadow-highlight);
    transform: scale(0.995);
}

.drop-zone-content {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.8rem;
    pointer-events: none; /* 防止子元素干擾拖曳事件 */
}

.upload-icon {
    color: var(--accent-blue);
    margin-bottom: 0.5rem;
    transition: var(--transition-smooth);
}

.drop-zone:hover .upload-icon {
    transform: translateY(-5px);
    color: var(--accent-purple);
}

.upload-text {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text-primary);
}

.upload-hint {
    font-size: 0.9rem;
    color: var(--text-muted);
}

.or-divider {
    font-size: 0.85rem;
    color: var(--text-muted);
    position: relative;
    width: 100%;
    max-width: 200px;
    margin: 0.5rem 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

.or-divider::before,
.or-divider::after {
    content: '';
    flex: 1;
    height: 1px;
    background: var(--border-color);
    margin: 0 10px;
}

/* 選擇檔案按鈕 */
.select-file-btn {
    pointer-events: auto; /* 允許點擊 */
    background: linear-gradient(135deg, var(--accent-blue), #0284c7);
    color: #ffffff;
    padding: 0.6rem 2rem;
    border-radius: 50px;
    font-weight: 500;
    font-size: 0.95rem;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(56, 189, 248, 0.3);
    transition: var(--transition-smooth);
    border: none;
}

.select-file-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(56, 189, 248, 0.4);
    background: linear-gradient(135deg, #0ea5e9, #0369a1);
}

.select-file-btn:active {
    transform: translateY(0);
}

/* 按鈕群組容器 */
.button-group {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
    justify-content: center;
    pointer-events: auto; /* 允許與按鈕群組互動 */
}

/* 顯示交易資料按鈕 */
.demo-file-btn {
    pointer-events: auto; /* 允許點擊 */
    background: linear-gradient(135deg, var(--accent-purple), #9333ea);
    color: #ffffff;
    padding: 0.6rem 2rem;
    border-radius: 50px;
    font-weight: 500;
    font-size: 0.95rem;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(192, 132, 252, 0.3);
    transition: var(--transition-smooth);
    border: none;
}

.demo-file-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(192, 132, 252, 0.4);
    background: linear-gradient(135deg, #a855f7, #7e22ce);
}

.demo-file-btn:active {
    transform: translateY(0);
}

/* -------------------------------------------------------------
 * 狀態提示區樣式 (Status Message Area)
 * ------------------------------------------------------------- */
.status-section {
    width: 100%;
    transition: var(--transition-smooth);
}

.status-card {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-md);
    padding: 1.5rem;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    border: 1px solid var(--border-color);
    box-shadow: var(--shadow-lg);
}

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

/* 旋轉載入動畫 */
.spinner {
    width: 24px;
    height: 24px;
    border: 3px solid rgba(56, 189, 248, 0.2);
    border-top: 3px solid var(--accent-blue);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

/* -------------------------------------------------------------
 * 資料與表格區樣式 (Data & Table Area)
 * ------------------------------------------------------------- */
.data-section {
    background: var(--bg-secondary);
    border-radius: var(--border-radius-lg);
    padding: 1.5rem;
    box-shadow: var(--shadow-lg);
    border: 1px solid rgba(255, 255, 255, 0.05);
    display: flex;
    flex-direction: column;
    gap: 1.2rem;
    animation: fadeIn 0.4s ease-out;
}

/* 工具欄：檔名與工作表切換 */
.data-toolbar {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 1rem;
}

@media (min-width: 768px) {
    .data-toolbar {
        flex-direction: row;
        justify-content: space-between;
        align-items: center;
    }
}

.file-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.file-icon {
    font-size: 1.5rem;
}

.file-name {
    font-size: 1.1rem;
    font-weight: 600;
    max-width: 250px;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
}

.sheet-count {
    font-size: 0.8rem;
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    padding: 0.2rem 0.6rem;
    border-radius: 20px;
}

/* 下載清理後資料按鈕樣式 */
.download-btn {
    background: linear-gradient(135deg, var(--accent-green), #059669);
    color: #ffffff;
    padding: 0.5rem 1.25rem;
    border-radius: 30px;
    font-weight: 500;
    font-size: 0.85rem;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(52, 211, 153, 0.2);
    transition: var(--transition-smooth);
    border: none;
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.download-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 15px rgba(52, 211, 153, 0.3);
    background: linear-gradient(135deg, #34d399, #047857);
}

.download-btn:active {
    transform: translateY(0);
}

/* 工作表標籤切換區 */
.sheet-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.sheet-tab {
    background: var(--bg-tertiary);
    color: var(--text-secondary);
    border: 1px solid transparent;
    padding: 0.4rem 1rem;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition-smooth);
}

.sheet-tab:hover {
    background: var(--border-hover);
    color: var(--text-primary);
}

.sheet-tab.active {
    background: linear-gradient(135deg, rgba(56, 189, 248, 0.15), rgba(192, 132, 252, 0.15));
    border-color: rgba(56, 189, 248, 0.4);
    color: var(--accent-blue);
    box-shadow: 0 0 10px rgba(56, 189, 248, 0.05);
}

/* KPI 數據看板區樣式 */
.kpi-container {
    display: grid;
    grid-template-columns: repeat(1, 1fr);
    gap: 1rem;
    width: 100%;
    margin-bottom: 0.5rem;
}

@media (min-width: 768px) {
    .kpi-container {
        grid-template-columns: repeat(3, 1fr);
    }
}

.kpi-card {
    background: rgba(30, 41, 59, 0.4);
    border: 1px solid var(--border-color);
    border-radius: var(--border-radius-md);
    padding: 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    transition: var(--transition-smooth);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
}

.kpi-card:hover {
    transform: translateY(-3px);
    background: rgba(30, 41, 59, 0.7);
}

#kpiCardCustomers:hover {
    box-shadow: 0 0 15px rgba(56, 189, 248, 0.15);
    border-color: rgba(56, 189, 248, 0.3);
}

#kpiCardRevenue:hover {
    box-shadow: 0 0 15px rgba(52, 211, 153, 0.15);
    border-color: rgba(52, 211, 153, 0.3);
}

#kpiCardAOV:hover {
    box-shadow: 0 0 15px rgba(192, 132, 252, 0.15);
    border-color: rgba(192, 132, 252, 0.3);
}

.kpi-label {
    font-size: 0.85rem;
    color: var(--text-secondary);
    font-weight: 500;
}

.kpi-value {
    font-size: 1.8rem;
    font-weight: 800;
    font-family: 'Outfit', sans-serif;
}

#kpiCustomers {
    color: var(--accent-blue);
}

#kpiRevenue {
    color: var(--accent-green);
}

#kpiAOV {
    color: var(--accent-purple);
}

/* 表格捲動包裝 */
.table-container {
    width: 100%;
    overflow-x: auto;
    border-radius: var(--border-radius-md);
    border: 1px solid var(--border-color);
    background: rgba(15, 23, 42, 0.3);
}

/* 精緻 Excel 表格樣式 */
.excel-table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
    text-align: left;
}

.excel-table th {
    background-color: var(--bg-tertiary);
    color: var(--text-primary);
    font-weight: 600;
    padding: 12px 16px;
    border-bottom: 2px solid var(--border-color);
    white-space: nowrap;
    position: sticky;
    top: 0;
}

.excel-table td {
    padding: 10px 16px;
    border-bottom: 1px solid var(--border-color);
    color: var(--text-secondary);
    white-space: nowrap;
    max-width: 300px;
    overflow: hidden;
    text-overflow: ellipsis;
}

.excel-table tr:last-child td {
    border-bottom: none;
}

.excel-table tr:hover td {
    background-color: rgba(255, 255, 255, 0.02);
    color: var(--text-primary);
}

/* 斑馬紋效果 */
.excel-table tr:nth-child(even) {
    background-color: rgba(255, 255, 255, 0.01);
}

/* -------------------------------------------------------------
 * 其他通用輔助樣式與動畫 (Helpers & Animations)
 * ------------------------------------------------------------- */
.hidden {
    display: none !important;
}

.app-footer {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-top: 1.5rem;
    padding-bottom: 1rem;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(10px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 針對錯誤訊息的特定樣式 */
.error-card {
    border-color: rgba(248, 113, 113, 0.3) !important;
    background: rgba(248, 113, 113, 0.05) !important;
}

.error-text {
    color: var(--accent-red) !important;
}

/* 自訂捲動軸樣式 */
.table-container::-webkit-scrollbar {
    height: 8px;
    width: 8px;
}

.table-container::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

.table-container::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 4px;
}

.table-container::-webkit-scrollbar-thumb:hover {
    background: var(--border-hover);
}