/* CashFlow AI - Modern Apple Design System 2024 */
/* Liquid Glass Design Language */

:root {
    /* Apple System Colors */
    --apple-blue: #007aff;
    --apple-purple: #af52de;
    --apple-pink: #ff2d55;
    --apple-orange: #ff9500;
    --apple-yellow: #ffcc00;
    --apple-green: #34c759;
    --apple-teal: #5ac8fa;
    --apple-indigo: #5856d6;
    
    /* Semantic Colors */
    --system-background: #f2f2f7;
    --system-background-secondary: #ffffff;
    --system-background-tertiary: #f2f2f7;
    --system-fill: rgba(120, 120, 128, 0.2);
    --system-fill-secondary: rgba(120, 120, 128, 0.16);
    --system-fill-tertiary: rgba(118, 118, 128, 0.12);
    --system-fill-quaternary: rgba(116, 116, 128, 0.08);
    
    /* Text Colors */
    --label-primary: rgba(0, 0, 0, 0.85);
    --label-secondary: rgba(60, 60, 67, 0.6);
    --label-tertiary: rgba(60, 60, 67, 0.3);
    --label-quaternary: rgba(60, 60, 67, 0.18);
    
    /* Material Effects */
    --glass-bg: rgba(255, 255, 255, 0.72);
    --glass-border: rgba(255, 255, 255, 0.3);
    --glass-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    
    /* Animation */
    --spring-bounce: cubic-bezier(0.68, -0.55, 0.265, 1.55);
    --spring-smooth: cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --ease-out-expo: cubic-bezier(0.19, 1, 0.22, 1);
}

/* Dark Mode */
@media (prefers-color-scheme: dark) {
    :root {
        --system-background: #000000;
        --system-background-secondary: #1c1c1e;
        --system-background-tertiary: #2c2c2e;
        --label-primary: rgba(255, 255, 255, 0.85);
        --label-secondary: rgba(235, 235, 245, 0.6);
        --label-tertiary: rgba(235, 235, 245, 0.3);
        --glass-bg: rgba(30, 30, 30, 0.72);
        --glass-border: rgba(255, 255, 255, 0.15);
    }
}

/* Base Reset with SF Pro */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'SF Pro Display', 'SF Pro Text', 'Helvetica Neue', Helvetica, Arial, sans-serif;
    font-size: 17px;
    line-height: 1.47059;
    font-weight: 400;
    letter-spacing: -0.022em;
    color: var(--label-primary);
    background: var(--system-background);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* Liquid Glass Components */
.glass-card {
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-radius: 20px;
    border: 0.5px solid var(--glass-border);
    box-shadow: var(--glass-shadow);
    transition: all 0.3s var(--spring-smooth);
    position: relative;
    overflow: hidden;
}

.glass-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, 
        transparent, 
        rgba(255, 255, 255, 0.5) 50%, 
        transparent);
    opacity: 0.5;
}

.glass-card:hover {
    transform: translateY(-2px);
    box-shadow: 
        0 12px 40px rgba(0, 0, 0, 0.12),
        inset 0 1px 1px rgba(255, 255, 255, 0.2);
}

/* Navigation Bar - iOS Style */
.app-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: 83px;
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    border-top: 0.5px solid var(--glass-border);
    padding-bottom: env(safe-area-inset-bottom);
    z-index: 1000;
}

.nav-items {
    display: flex;
    justify-content: space-around;
    align-items: center;
    height: 100%;
    padding: 0 8px;
}

.nav-item {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    text-decoration: none;
    color: var(--label-secondary);
    transition: all 0.2s var(--spring-smooth);
    padding: 8px;
    border-radius: 12px;
    position: relative;
}

.nav-item.active {
    color: var(--apple-blue);
}

.nav-item:active {
    transform: scale(0.95);
}

.nav-icon {
    width: 28px;
    height: 28px;
    position: relative;
}

.nav-label {
    font-size: 10px;
    font-weight: 500;
    letter-spacing: -0.01em;
}

/* Header with Dynamic Island Feel */
.app-header {
    background: var(--glass-bg);
    backdrop-filter: blur(20px) saturate(180%);
    -webkit-backdrop-filter: blur(20px) saturate(180%);
    padding: 20px 20px 16px;
    position: sticky;
    top: 0;
    z-index: 999;
    border-bottom: 0.5px solid var(--glass-border);
}

.header-content {
    max-width: 1200px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.header-title {
    font-size: 34px;
    font-weight: 700;
    letter-spacing: -0.035em;
    color: var(--label-primary);
}

/* Upload Area - Modern Style */
.upload-zone {
    background: var(--system-fill-quaternary);
    border-radius: 16px;
    padding: 40px;
    text-align: center;
    transition: all 0.3s var(--spring-smooth);
    cursor: pointer;
    position: relative;
    overflow: hidden;
}

.upload-zone::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, var(--apple-blue) 0%, transparent 70%);
    opacity: 0;
    transition: opacity 0.3s ease;
}

.upload-zone:hover {
    background: var(--system-fill-tertiary);
}

.upload-zone.drag-active {
    background: rgba(0, 122, 255, 0.1);
    border: 2px dashed var(--apple-blue);
}

.upload-zone.drag-active::before {
    opacity: 0.1;
}

/* Financial Cards */
.metric-card {
    background: var(--glass-bg);
    backdrop-filter: blur(16px) saturate(180%);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    border-radius: 16px;
    border: 0.5px solid var(--glass-border);
    padding: 20px;
    transition: all 0.3s var(--spring-smooth);
}

.metric-label {
    font-size: 13px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: -0.01em;
    color: var(--label-secondary);
    margin-bottom: 4px;
}

.metric-value {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.035em;
    color: var(--label-primary);
    font-feature-settings: "tnum";
}

.metric-trend {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    font-size: 13px;
    font-weight: 600;
    padding: 4px 8px;
    border-radius: 6px;
    margin-top: 8px;
}

.metric-trend.positive {
    color: var(--apple-green);
    background: rgba(52, 199, 89, 0.1);
}

.metric-trend.negative {
    color: var(--apple-pink);
    background: rgba(255, 45, 85, 0.1);
}

/* Category Pills */
.category-pill {
    display: inline-flex;
    align-items: center;
    padding: 6px 12px;
    border-radius: 100px;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: -0.01em;
    background: var(--system-fill-secondary);
    color: var(--label-primary);
    transition: all 0.2s var(--spring-smooth);
}

.category-pill:hover {
    transform: scale(1.05);
}

/* Receipt List Items */
.receipt-item {
    background: var(--glass-bg);
    backdrop-filter: blur(8px);
    -webkit-backdrop-filter: blur(8px);
    border-radius: 12px;
    padding: 16px;
    margin-bottom: 8px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    transition: all 0.2s var(--spring-smooth);
    border: 0.5px solid transparent;
}

.receipt-item:hover {
    border-color: var(--glass-border);
    transform: translateX(4px);
}

.receipt-info {
    flex: 1;
}

.receipt-store {
    font-size: 17px;
    font-weight: 600;
    letter-spacing: -0.022em;
    color: var(--label-primary);
    margin-bottom: 2px;
}

.receipt-date {
    font-size: 13px;
    color: var(--label-secondary);
}

.receipt-amount {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.03em;
    color: var(--label-primary);
    font-feature-settings: "tnum";
}

/* Animations */
@keyframes slideInUp {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes pulseGlow {
    0%, 100% {
        box-shadow: 0 0 0 0 rgba(0, 122, 255, 0.4);
    }
    50% {
        box-shadow: 0 0 0 8px rgba(0, 122, 255, 0);
    }
}

.animate-in {
    animation: slideInUp 0.6s var(--ease-out-expo) forwards;
}

/* Loading States */
.skeleton {
    background: linear-gradient(90deg, 
        var(--system-fill-tertiary) 0%, 
        var(--system-fill-secondary) 50%, 
        var(--system-fill-tertiary) 100%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: 6px;
}

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

/* Buttons */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 17px;
    font-weight: 600;
    letter-spacing: -0.022em;
    padding: 12px 24px;
    border-radius: 100px;
    border: none;
    cursor: pointer;
    transition: all 0.2s var(--spring-smooth);
    text-decoration: none;
    position: relative;
    overflow: hidden;
}

.btn-primary {
    background: var(--apple-blue);
    color: white;
}

.btn-primary:hover {
    background: #0051d5;
    transform: scale(1.02);
}

.btn-primary:active {
    transform: scale(0.98);
}

/* Responsive */
@media (max-width: 768px) {
    .header-title {
        font-size: 28px;
    }
    
    .metric-value {
        font-size: 28px;
    }
}