/* 定義全域變數與主題色彩 (科技藍風格) */
:root {
    --primary-color: #0ea5e9; /* 科技藍 */
    --primary-hover: #38bdf8; /* 科技亮藍 */
    --danger-color: #f43f5e;
    --danger-hover: #fb7185;
    --bg-color: #0f172a; /* 深邃太空藍背景 */
    --card-bg: #1e293b; /* 卡片深色背景 */
    --text-primary: #f8fafc; /* 亮白文字 */
    --text-secondary: #94a3b8; /* 灰藍色次要文字 */
    --border-color: #334155; /* 邊框顏色 */
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.5);
    --shadow-md: 0 4px 10px rgba(14, 165, 233, 0.2); /* 基礎發光 */
    --shadow-lg: 0 0 30px rgba(14, 165, 233, 0.8), 0 0 10px rgba(14, 165, 233, 0.5); /* 強烈科技藍發光效果 */
}

/* 基礎設定 */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: 'Inter', system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-primary);
    line-height: 1.5;
    -webkit-font-smoothing: antialiased;
}

/* 佈局與容器 */
.app-container {
    max-width: 1000px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
}

.app-header {
    text-align: center;
    margin-bottom: 3rem;
}

.app-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    letter-spacing: 0.05em;
    background: linear-gradient(135deg, #0ea5e9, #2dd4bf); /* 藍到青的漸層 */
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    text-shadow: 0 0 20px rgba(14, 165, 233, 0.4); /* 文字發光 */
    margin-bottom: 0.5rem;
    text-transform: uppercase;
}

.app-header p {
    color: var(--text-secondary);
    font-size: 1.125rem;
    letter-spacing: 0.05em;
}

/* 卡片設計 */
.card {
    background: var(--card-bg);
    border-radius: var(--border-radius);
    padding: 2rem;
    box-shadow: var(--shadow-md);
    border: 1px solid rgba(14, 165, 233, 0.4); /* 更明顯的邊框 */
    transition: var(--transition);
    margin-bottom: 2rem;
}

.card:hover {
    box-shadow: var(--shadow-lg);
    border-color: rgba(14, 165, 233, 1); /* hover 時更亮 */
}

.card h2 {
    font-size: 1.25rem;
    font-weight: 600;
    margin-bottom: 1.5rem;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 0.5rem;
    letter-spacing: 0.05em;
}

/* 表單樣式 */
.product-form {
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.form-row {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.25rem;
}

.form-group {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
}

label {
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--text-secondary);
    letter-spacing: 0.05em;
}

input {
    width: 100%;
    padding: 0.75rem 1rem;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1rem;
    color: var(--text-primary);
    background-color: #0f172a; /* 深色輸入框 */
    transition: var(--transition);
}

input:focus {
    outline: none;
    border-color: var(--primary-hover);
    box-shadow: 0 0 15px rgba(14, 165, 233, 0.6); /* 增強輸入框發光 */
    background-color: #1e293b;
}

input::placeholder {
    color: #475569;
}

/* 按鈕樣式 */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.75rem 1.5rem;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    letter-spacing: 0.05em;
}

.btn-primary {
    background-color: var(--primary-color);
    color: #0f172a; /* 深色文字增加對比 */
    box-shadow: 0 0 15px rgba(14, 165, 233, 0.5); /* 預設發光 */
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    transform: translateY(-1px);
    box-shadow: 0 0 25px rgba(14, 165, 233, 0.9); /* 超亮發光 */
}

.btn-secondary {
    background-color: #334155;
    color: var(--text-primary);
}

.btn-secondary:hover {
    background-color: #475569;
}

.btn-icon {
    padding: 0.5rem;
    background: transparent;
    color: var(--text-secondary);
    border-radius: 6px;
}

.btn-icon:hover {
    background-color: rgba(14, 165, 233, 0.1);
    color: var(--primary-color);
}

.btn-danger {
    background: transparent;
    color: var(--danger-color);
    padding: 0.5rem 1rem;
    border: 1px solid var(--danger-color);
    border-radius: 6px;
}

.btn-danger:hover {
    background: var(--danger-color);
    color: white;
    box-shadow: 0 0 10px rgba(244, 63, 94, 0.4);
}

.btn-edit {
    background: transparent;
    color: var(--primary-color);
    padding: 0.5rem 1rem;
    border: 1px solid var(--primary-color);
    border-radius: 6px;
    margin-right: 0.5rem;
}

.btn-edit:hover {
    background: var(--primary-color);
    color: #0f172a;
    box-shadow: 0 0 10px rgba(14, 165, 233, 0.4);
}

/* 列表與表格樣式 */
.list-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
}

.table-responsive {
    overflow-x: auto;
}

.data-table {
    width: 100%;
    border-collapse: separate;
    border-spacing: 0;
}

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

.data-table th {
    font-weight: 600;
    color: var(--text-secondary);
    font-size: 0.875rem;
    text-transform: uppercase;
    letter-spacing: 0.1em;
    background-color: #0f172a;
}

.data-table th:first-child {
    border-top-left-radius: 8px;
    border-bottom-left-radius: 8px;
}

.data-table th:last-child {
    border-top-right-radius: 8px;
    border-bottom-right-radius: 8px;
}

.data-table tr {
    transition: var(--transition);
}

.data-table tbody tr:hover {
    background-color: rgba(14, 165, 233, 0.1); 
    box-shadow: inset 0 0 15px rgba(14, 165, 233, 0.2); /* 列表內發光 */
}

.price-tag {
    font-family: monospace;
    font-size: 1.1rem;
    color: var(--primary-hover);
    font-weight: 600;
    letter-spacing: 0.05em;
    text-shadow: 0 0 8px rgba(14, 165, 233, 0.5); /* 價格發光 */
}

.qty-tag {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 9999px;
    font-size: 0.875rem;
    font-weight: 600;
    background-color: rgba(14, 165, 233, 0.15);
    color: var(--primary-hover);
    border: 1px solid rgba(14, 165, 233, 0.3);
}

.qty-tag.low {
    background-color: rgba(244, 63, 94, 0.15);
    color: var(--danger-hover);
    border-color: rgba(244, 63, 94, 0.3);
}

/* 狀態顯示 */
.hidden {
    display: none !important;
}

.loading-indicator {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 3rem 0;
    color: var(--text-secondary);
    gap: 1rem;
}

.spinner {
    width: 32px;
    height: 32px;
    border: 3px solid rgba(14, 165, 233, 0.2);
    border-top-color: var(--primary-color);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

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

.empty-state {
    text-align: center;
    padding: 4rem 2rem;
    color: var(--text-secondary);
}

.empty-state svg {
    margin-bottom: 1rem;
    color: #475569;
}

/* RWD 調整 */
@media (max-width: 640px) {
    .form-row {
        grid-template-columns: 1fr;
    }
    
    .data-table th,
    .data-table td {
        padding: 0.75rem 0.5rem;
    }
}

/* Auth 區塊與彈窗 */
.auth-container {
    margin-top: 1.5rem;
    display: flex;
    justify-content: center;
    gap: 1rem;
    align-items: center;
}

#userInfo {
    color: var(--primary-color);
    font-weight: 600;
    letter-spacing: 0.05em;
}

.auth-modal-overlay {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 1000;
    opacity: 0;
    pointer-events: none;
    transition: var(--transition);
}

.auth-modal-overlay.active {
    opacity: 1;
    pointer-events: auto;
}

.auth-modal {
    background: var(--card-bg);
    padding: 2rem;
    border-radius: var(--border-radius);
    width: 90%;
    max-width: 400px;
    border: 1px solid rgba(14, 165, 233, 0.3);
    box-shadow: var(--shadow-lg);
    transform: translateY(-20px);
    transition: var(--transition);
}

.auth-modal-overlay.active .auth-modal {
    transform: translateY(0);
}

.auth-modal h2 {
    color: var(--primary-color);
    margin-bottom: 1.5rem;
    text-align: center;
    font-size: 1.5rem;
    letter-spacing: 0.05em;
}