/**
 * QLK Pro Modern UI - Version 4.0
 * Modern, Clean & Professional Design
 * @package QLK_Pro
 */

/* ========================================
   CSS Variables - Design System
   ======================================== */
:root {
    /* Primary Colors */
    --qlk-primary: #6366f1;
    --qlk-primary-light: #818cf8;
    --qlk-primary-dark: #4f46e5;
    --qlk-primary-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%);
    
    /* Secondary Colors */
    --qlk-secondary: #64748b;
    --qlk-secondary-light: #94a3b8;
    
    /* Status Colors */
    --qlk-success: #10b981;
    --qlk-success-light: #d1fae5;
    --qlk-warning: #f59e0b;
    --qlk-warning-light: #fef3c7;
    --qlk-danger: #ef4444;
    --qlk-danger-light: #fee2e2;
    --qlk-info: #3b82f6;
    --qlk-info-light: #dbeafe;
    
    /* Neutral Colors */
    --qlk-white: #ffffff;
    --qlk-gray-50: #f8fafc;
    --qlk-gray-100: #f1f5f9;
    --qlk-gray-200: #e2e8f0;
    --qlk-gray-300: #cbd5e1;
    --qlk-gray-400: #94a3b8;
    --qlk-gray-500: #64748b;
    --qlk-gray-600: #475569;
    --qlk-gray-700: #334155;
    --qlk-gray-800: #1e293b;
    --qlk-gray-900: #0f172a;
    
    /* Shadows */
    --qlk-shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --qlk-shadow: 0 1px 3px 0 rgb(0 0 0 / 0.1), 0 1px 2px -1px rgb(0 0 0 / 0.1);
    --qlk-shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1), 0 2px 4px -2px rgb(0 0 0 / 0.1);
    --qlk-shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1), 0 4px 6px -4px rgb(0 0 0 / 0.1);
    --qlk-shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1), 0 8px 10px -6px rgb(0 0 0 / 0.1);
    --qlk-shadow-glow: 0 0 40px rgba(99, 102, 241, 0.15);
    
    /* Border Radius */
    --qlk-radius-sm: 6px;
    --qlk-radius: 12px;
    --qlk-radius-lg: 16px;
    --qlk-radius-xl: 24px;
    --qlk-radius-full: 9999px;
    
    /* Transitions */
    --qlk-transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --qlk-transition-slow: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    
    /* Font */
    --qlk-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

/* ========================================
   Base Styles
   ======================================== */
.qlk-app-container {
    font-family: var(--qlk-font);
    background: linear-gradient(180deg, var(--qlk-gray-50) 0%, var(--qlk-gray-100) 100%);
    min-height: 100vh;
    color: var(--qlk-gray-800);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* ========================================
   App Header - Modern Glass Effect
   ======================================== */
.qlk-app-header {
    background: var(--qlk-primary-gradient);
    padding: 24px 20px 80px;
    position: relative;
    overflow: hidden;
}

.qlk-app-header::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 300px;
    height: 300px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    pointer-events: none;
}

.qlk-app-header::after {
    content: '';
    position: absolute;
    bottom: -30%;
    left: -10%;
    width: 200px;
    height: 200px;
    background: rgba(255, 255, 255, 0.08);
    border-radius: 50%;
    pointer-events: none;
}

.qlk-header-content {
    position: relative;
    z-index: 1;
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: 0 auto;
}

.qlk-header-title {
    color: var(--qlk-white);
    font-size: 24px;
    font-weight: 700;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 12px;
}

.qlk-header-title-icon {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: var(--qlk-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 20px;
    backdrop-filter: blur(10px);
}

.qlk-header-subtitle {
    color: rgba(255, 255, 255, 0.8);
    font-size: 14px;
    margin-top: 4px;
}

.qlk-header-actions {
    display: flex;
    gap: 12px;
}

.qlk-header-btn {
    background: rgba(255, 255, 255, 0.15);
    border: 1px solid rgba(255, 255, 255, 0.2);
    color: var(--qlk-white);
    padding: 10px 16px;
    border-radius: var(--qlk-radius);
    font-size: 14px;
    font-weight: 500;
    cursor: pointer;
    transition: var(--qlk-transition);
    backdrop-filter: blur(10px);
    display: flex;
    align-items: center;
    gap: 8px;
    text-decoration: none;
}

.qlk-header-btn:hover {
    background: rgba(255, 255, 255, 0.25);
    transform: translateY(-2px);
}

/* ========================================
   Main Content Area
   ======================================== */
.qlk-main-content {
    max-width: 1200px;
    margin: -60px auto 0;
    padding: 0 20px 100px;
    position: relative;
    z-index: 2;
}

/* ========================================
   Stats Cards - Floating Glass Cards
   ======================================== */
.qlk-stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.qlk-stat-card {
    background: var(--qlk-white);
    border-radius: var(--qlk-radius-lg);
    padding: 20px;
    box-shadow: var(--qlk-shadow-lg);
    transition: var(--qlk-transition);
    position: relative;
    overflow: hidden;
}

.qlk-stat-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--qlk-primary-gradient);
    opacity: 0;
    transition: var(--qlk-transition);
}

.qlk-stat-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--qlk-shadow-xl), var(--qlk-shadow-glow);
}

.qlk-stat-card:hover::before {
    opacity: 1;
}

.qlk-stat-icon {
    width: 48px;
    height: 48px;
    border-radius: var(--qlk-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
    margin-bottom: 12px;
}

.qlk-stat-icon.primary { background: var(--qlk-info-light); }
.qlk-stat-icon.success { background: var(--qlk-success-light); }
.qlk-stat-icon.warning { background: var(--qlk-warning-light); }
.qlk-stat-icon.danger { background: var(--qlk-danger-light); }

.qlk-stat-value {
    font-size: 28px;
    font-weight: 700;
    color: var(--qlk-gray-900);
    line-height: 1;
    margin-bottom: 4px;
}

.qlk-stat-label {
    font-size: 13px;
    color: var(--qlk-gray-500);
    font-weight: 500;
}

/* ========================================
   Content Cards
   ======================================== */
.qlk-card {
    background: var(--qlk-white);
    border-radius: var(--qlk-radius-lg);
    box-shadow: var(--qlk-shadow-md);
    overflow: hidden;
    margin-bottom: 20px;
}

.qlk-card-header {
    padding: 20px 24px;
    border-bottom: 1px solid var(--qlk-gray-100);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.qlk-card-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--qlk-gray-900);
    margin: 0;
    display: flex;
    align-items: center;
    gap: 10px;
}

.qlk-card-body {
    padding: 24px;
}

.qlk-card-footer {
    padding: 16px 24px;
    background: var(--qlk-gray-50);
    border-top: 1px solid var(--qlk-gray-100);
}

/* ========================================
   Quick Actions - Modern Grid
   ======================================== */
.qlk-actions-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 16px;
}

.qlk-action-btn {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 24px 16px;
    border-radius: var(--qlk-radius-lg);
    text-decoration: none;
    color: var(--qlk-white);
    font-weight: 600;
    font-size: 14px;
    transition: var(--qlk-transition);
    position: relative;
    overflow: hidden;
}

.qlk-action-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(180deg, rgba(255,255,255,0.1) 0%, rgba(255,255,255,0) 100%);
    pointer-events: none;
}

.qlk-action-btn:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: var(--qlk-shadow-xl);
    color: var(--qlk-white);
}

.qlk-action-btn.scan { background: linear-gradient(135deg, #6366f1 0%, #8b5cf6 100%); }
.qlk-action-btn.manual { background: linear-gradient(135deg, #10b981 0%, #059669 100%); }
.qlk-action-btn.stock-in { background: linear-gradient(135deg, #3b82f6 0%, #2563eb 100%); }
.qlk-action-btn.stock-out { background: linear-gradient(135deg, #f59e0b 0%, #d97706 100%); }

.qlk-action-icon {
    font-size: 32px;
    margin-bottom: 8px;
}

/* ========================================
   Device List - Modern Cards
   ======================================== */
.qlk-device-list {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.qlk-device-item {
    display: flex;
    align-items: center;
    gap: 16px;
    padding: 16px;
    background: var(--qlk-white);
    border-radius: var(--qlk-radius);
    border: 1px solid var(--qlk-gray-200);
    transition: var(--qlk-transition);
    cursor: pointer;
}

.qlk-device-item:hover {
    border-color: var(--qlk-primary-light);
    box-shadow: var(--qlk-shadow-md);
    transform: translateX(4px);
}

.qlk-device-image {
    width: 56px;
    height: 56px;
    border-radius: var(--qlk-radius);
    object-fit: cover;
    background: var(--qlk-gray-100);
}

.qlk-device-info {
    flex: 1;
    min-width: 0;
}

.qlk-device-name {
    font-size: 15px;
    font-weight: 600;
    color: var(--qlk-gray-900);
    margin: 0 0 4px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.qlk-device-sku {
    font-size: 13px;
    color: var(--qlk-gray-500);
}

.qlk-device-stock {
    text-align: right;
}

.qlk-stock-number {
    font-size: 20px;
    font-weight: 700;
    color: var(--qlk-gray-900);
}

.qlk-stock-label {
    font-size: 12px;
    color: var(--qlk-gray-500);
}

.qlk-stock-low .qlk-stock-number { color: var(--qlk-warning); }
.qlk-stock-out .qlk-stock-number { color: var(--qlk-danger); }

/* ========================================
   Buttons - Modern Style
   ======================================== */
.qlk-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: var(--qlk-radius);
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: var(--qlk-transition);
    text-decoration: none;
}

.qlk-btn-primary {
    background: var(--qlk-primary-gradient);
    color: var(--qlk-white);
    box-shadow: 0 4px 14px rgba(99, 102, 241, 0.4);
}

.qlk-btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(99, 102, 241, 0.5);
}

.qlk-btn-secondary {
    background: var(--qlk-white);
    color: var(--qlk-gray-700);
    border: 1px solid var(--qlk-gray-300);
}

.qlk-btn-secondary:hover {
    background: var(--qlk-gray-50);
    border-color: var(--qlk-gray-400);
}

.qlk-btn-success {
    background: linear-gradient(135deg, #10b981 0%, #059669 100%);
    color: var(--qlk-white);
    box-shadow: 0 4px 14px rgba(16, 185, 129, 0.4);
}

.qlk-btn-danger {
    background: linear-gradient(135deg, #ef4444 0%, #dc2626 100%);
    color: var(--qlk-white);
    box-shadow: 0 4px 14px rgba(239, 68, 68, 0.4);
}

.qlk-btn-lg {
    padding: 16px 32px;
    font-size: 16px;
    border-radius: var(--qlk-radius-lg);
}

.qlk-btn-block {
    width: 100%;
}

/* ========================================
   Form Elements - Modern Input
   ======================================== */
.qlk-form-group {
    margin-bottom: 20px;
}

.qlk-form-label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    color: var(--qlk-gray-700);
    margin-bottom: 8px;
}

.qlk-form-input {
    width: 100%;
    padding: 14px 16px;
    border: 2px solid var(--qlk-gray-200);
    border-radius: var(--qlk-radius);
    font-size: 16px;
    color: var(--qlk-gray-900);
    background: var(--qlk-white);
    transition: var(--qlk-transition);
    box-sizing: border-box;
}

.qlk-form-input:focus {
    outline: none;
    border-color: var(--qlk-primary);
    box-shadow: 0 0 0 4px rgba(99, 102, 241, 0.1);
}

.qlk-form-input::placeholder {
    color: var(--qlk-gray-400);
}

/* ========================================
   Search Box - Modern Style
   ======================================== */
.qlk-search-box {
    position: relative;
}

.qlk-search-input {
    width: 100%;
    padding: 16px 16px 16px 52px;
    border: 2px solid var(--qlk-gray-200);
    border-radius: var(--qlk-radius-lg);
    font-size: 16px;
    background: var(--qlk-white);
    transition: var(--qlk-transition);
}

.qlk-search-input:focus {
    border-color: var(--qlk-primary);
    box-shadow: var(--qlk-shadow-lg), 0 0 0 4px rgba(99, 102, 241, 0.1);
}

.qlk-search-icon {
    position: absolute;
    left: 18px;
    top: 50%;
    transform: translateY(-50%);
    font-size: 20px;
    color: var(--qlk-gray-400);
}

/* ========================================
   Badges & Tags
   ======================================== */
.qlk-badge {
    display: inline-flex;
    align-items: center;
    padding: 4px 12px;
    border-radius: var(--qlk-radius-full);
    font-size: 12px;
    font-weight: 600;
}

.qlk-badge-primary { background: var(--qlk-info-light); color: var(--qlk-info); }
.qlk-badge-success { background: var(--qlk-success-light); color: var(--qlk-success); }
.qlk-badge-warning { background: var(--qlk-warning-light); color: var(--qlk-warning); }
.qlk-badge-danger { background: var(--qlk-danger-light); color: var(--qlk-danger); }

/* ========================================
   Bottom Navigation - Modern Tab Bar
   ======================================== */
.qlk-bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: var(--qlk-white);
    border-top: 1px solid var(--qlk-gray-200);
    padding: 8px 16px;
    padding-bottom: calc(8px + env(safe-area-inset-bottom));
    display: flex;
    justify-content: space-around;
    z-index: 1000;
    box-shadow: 0 -4px 20px rgba(0, 0, 0, 0.08);
}

.qlk-nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 8px 16px;
    color: var(--qlk-gray-500);
    text-decoration: none;
    font-size: 11px;
    font-weight: 500;
    transition: var(--qlk-transition);
    border-radius: var(--qlk-radius);
}

.qlk-nav-item.active {
    color: var(--qlk-primary);
    background: rgba(99, 102, 241, 0.1);
}

.qlk-nav-icon {
    font-size: 24px;
    margin-bottom: 4px;
}

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

@keyframes slideUp {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

@keyframes pulse {
    0%, 100% { transform: scale(1); }
    50% { transform: scale(1.05); }
}

.qlk-animate-fade { animation: fadeIn 0.3s ease-out; }
.qlk-animate-slide { animation: slideUp 0.4s ease-out; }
.qlk-animate-pulse { animation: pulse 2s infinite; }

/* ========================================
   Loading States
   ======================================== */
.qlk-skeleton {
    background: linear-gradient(90deg, var(--qlk-gray-200) 25%, var(--qlk-gray-100) 50%, var(--qlk-gray-200) 75%);
    background-size: 200% 100%;
    animation: skeleton 1.5s infinite;
    border-radius: var(--qlk-radius-sm);
}

@keyframes skeleton {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

.qlk-spinner {
    width: 24px;
    height: 24px;
    border: 3px solid var(--qlk-gray-200);
    border-top-color: var(--qlk-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

/* ========================================
   Empty States
   ======================================== */
.qlk-empty-state {
    text-align: center;
    padding: 48px 24px;
}

.qlk-empty-icon {
    font-size: 64px;
    margin-bottom: 16px;
    opacity: 0.5;
}

.qlk-empty-title {
    font-size: 18px;
    font-weight: 600;
    color: var(--qlk-gray-700);
    margin: 0 0 8px;
}

.qlk-empty-text {
    font-size: 14px;
    color: var(--qlk-gray-500);
    margin: 0;
}

/* ========================================
   Responsive Design
   ======================================== */
@media (max-width: 768px) {
    .qlk-app-header {
        padding: 20px 16px 70px;
    }
    
    .qlk-header-title {
        font-size: 20px;
    }
    
    .qlk-main-content {
        padding: 0 16px 120px;
        margin-top: -50px;
    }
    
    .qlk-stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px;
    }
    
    .qlk-stat-card {
        padding: 16px;
    }
    
    .qlk-stat-value {
        font-size: 24px;
    }
    
    .qlk-actions-grid {
        gap: 12px;
    }
    
    .qlk-action-btn {
        padding: 20px 12px;
    }
    
    .qlk-action-icon {
        font-size: 28px;
    }
}

@media (max-width: 480px) {
    .qlk-stats-grid {
        grid-template-columns: 1fr 1fr;
    }
    
    .qlk-stat-icon {
        width: 40px;
        height: 40px;
        font-size: 20px;
    }
    
    .qlk-stat-value {
        font-size: 20px;
    }
    
    .qlk-stat-label {
        font-size: 12px;
    }
}

/* ========================================
   Dark Mode Support (Optional)
   ======================================== */
@media (prefers-color-scheme: dark) {
    .qlk-app-container.dark-mode {
        --qlk-white: #1e293b;
        --qlk-gray-50: #0f172a;
        --qlk-gray-100: #1e293b;
        --qlk-gray-200: #334155;
        --qlk-gray-800: #f1f5f9;
        --qlk-gray-900: #f8fafc;
    }
}