/*
 * Modern Design System for Rivlup PWA
 * Inspired by Threads, X, Instagram
 */

:root {
    /* Brand Colors - Modern Dark Gray */
    --color-primary: #1f2937;
    --color-primary-hover: #111827;
    --color-primary-light: #f3f4f6;
    --color-primary-dark: #0f172a;

    /* Neutral Colors - Clean & Minimal */
    --color-bg: #ffffff;
    --color-bg-secondary: #fafafa;
    --color-bg-tertiary: #f5f5f5;
    --color-surface: #ffffff;
    --color-border: #e5e5e5;
    --color-border-light: #f0f0f0;

    /* Text Colors - Clear Hierarchy */
    --color-text-primary: #0a0a0a;
    --color-text-secondary: #737373;
    --color-text-tertiary: #a3a3a3;
    --color-text-inverse: #ffffff;

    /* Interactive Colors */
    --color-link: #0a0a0a;
    --color-link-hover: #374151;
    --color-success: #16a34a;
    --color-error: #dc2626;
    --color-warning: #ea580c;
    --color-info: #0284c7;

    /* Shadows - Subtle & Modern */
    --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.03);
    --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -2px rgba(0, 0, 0, 0.03);
    --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.05), 0 4px 6px -4px rgba(0, 0, 0, 0.03);
    --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.06), 0 8px 10px -6px rgba(0, 0, 0, 0.04);

    /* Border Radius - Smooth & Friendly */
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 20px;
    --radius-2xl: 24px;
    --radius-full: 9999px;

    /* Spacing - Consistent & Harmonious */
    --space-xs: 4px;
    --space-sm: 8px;
    --space-md: 12px;
    --space-lg: 16px;
    --space-xl: 24px;
    --space-2xl: 32px;
    --space-3xl: 48px;

    /* Typography - Clear & Readable */
    --font-sans: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'Noto Sans KR', Roboto, sans-serif;
    --font-size-xs: 12px;
    --font-size-sm: 14px;
    --font-size-base: 15px;
    --font-size-lg: 17px;
    --font-size-xl: 20px;
    --font-size-2xl: 24px;
    --font-size-3xl: 30px;
    --font-size-4xl: 36px;

    --font-weight-normal: 400;
    --font-weight-medium: 500;
    --font-weight-semibold: 600;
    --font-weight-bold: 700;

    --line-height-tight: 1.25;
    --line-height-normal: 1.5;
    --line-height-relaxed: 1.75;

    /* Transitions - Smooth & Natural */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Modern Base Styles */
* {
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    box-sizing: border-box;
}

body {
    font-family: var(--font-sans);
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
    color: var(--color-text-primary);
    background-color: var(--color-bg);
}

/* Modern Card Styles */
.modern-card {
    background: var(--color-surface);
    border: 1px solid var(--color-border-light);
    border-radius: var(--radius-xl);
    transition: all var(--transition-base);
}

.modern-card:hover {
    border-color: var(--color-border);
    box-shadow: var(--shadow-md);
}

.modern-card-interactive {
    cursor: pointer;
}

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

.modern-card-interactive:active {
    transform: translateY(0);
}

/* Modern Button Styles - Threads/Instagram inspired */
.btn-modern {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-weight: var(--font-weight-semibold);
    font-size: var(--font-size-sm);
    padding: 10px 20px;
    border-radius: var(--radius-lg);
    border: none;
    cursor: pointer;
    transition: all var(--transition-base);
    outline: none;
    text-decoration: none;
}

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

.btn-primary {
    background-color: var(--color-primary);
    color: var(--color-text-inverse);
}

.btn-primary:hover {
    background-color: var(--color-primary-hover);
}

.btn-secondary {
    background-color: var(--color-bg-tertiary);
    color: var(--color-text-primary);
}

.btn-secondary:hover {
    background-color: var(--color-border);
}

.btn-ghost {
    background-color: transparent;
    color: var(--color-text-primary);
}

.btn-ghost:hover {
    background-color: var(--color-bg-secondary);
}

/* Modern Avatar Styles */
.avatar {
    border-radius: var(--radius-full);
    object-fit: cover;
    background-color: var(--color-bg-tertiary);
}

.avatar-ring {
    padding: 2px;
    background: linear-gradient(45deg, var(--color-primary), #ec4899);
}

/* Modern Input Styles */
.input-modern {
    width: 100%;
    padding: 12px 16px;
    font-size: var(--font-size-base);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    background-color: var(--color-bg);
    transition: all var(--transition-base);
}

.input-modern:focus {
    outline: none;
    border-color: var(--color-primary);
    box-shadow: 0 0 0 3px var(--color-primary-light);
}

/* Modern Badge Styles */
.badge-modern {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 4px 12px;
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-medium);
    border-radius: var(--radius-full);
    background-color: var(--color-bg-tertiary);
    color: var(--color-text-secondary);
}

/* Modern Divider */
.divider-modern {
    height: 1px;
    background-color: var(--color-border-light);
    border: none;
}

/* Typography Utilities */
.text-heading-1 {
    font-size: var(--font-size-4xl);
    font-weight: var(--font-weight-bold);
    line-height: var(--line-height-tight);
}

.text-heading-2 {
    font-size: var(--font-size-3xl);
    font-weight: var(--font-weight-bold);
    line-height: var(--line-height-tight);
}

.text-heading-3 {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-semibold);
    line-height: var(--line-height-tight);
}

.text-body {
    font-size: var(--font-size-base);
    line-height: var(--line-height-normal);
}

.text-caption {
    font-size: var(--font-size-sm);
    color: var(--color-text-secondary);
}

/* Modern Tab/Category Navigation - Instagram/Threads style */
.tab-nav {
    display: flex;
    gap: var(--space-xs);
    overflow-x: auto;
    -webkit-overflow-scrolling: touch;
    scrollbar-width: none;
}

.tab-nav::-webkit-scrollbar {
    display: none;
}

.tab-item {
    flex-shrink: 0;
    padding: 6px 14px;
    font-size: 0.8125rem; /* 13px - 기존보다 작게 */
    font-weight: var(--font-weight-semibold);
    color: var(--color-text-secondary);
    background-color: transparent;
    border: none;
    border-radius: var(--radius-full);
    cursor: pointer;
    transition: all var(--transition-base);
    white-space: nowrap;
}

.tab-item:hover {
    background-color: var(--color-bg-secondary);
    color: var(--color-text-primary);
}

.tab-item.active {
    background-color: var(--color-text-primary);
    color: var(--color-text-inverse);
}

/* Modern Stats Display */
.stat-modern {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--space-xs);
}

.stat-value {
    font-size: var(--font-size-2xl);
    font-weight: var(--font-weight-bold);
    color: var(--color-text-primary);
}

.stat-label {
    font-size: var(--font-size-xs);
    font-weight: var(--font-weight-medium);
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

/* Smooth Animations */
@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

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

@keyframes scaleIn {
    from {
        opacity: 0;
        transform: scale(0.95);
    }
    to {
        opacity: 1;
        transform: scale(1);
    }
}

.animate-fade-in {
    animation: fadeIn var(--transition-slow) ease-out;
}

.animate-slide-up {
    animation: slideUp var(--transition-slow) ease-out;
}

.animate-scale-in {
    animation: scaleIn var(--transition-base) ease-out;
}

/* Loading States */
.skeleton {
    background: linear-gradient(
        90deg,
        var(--color-bg-tertiary) 0%,
        var(--color-bg-secondary) 50%,
        var(--color-bg-tertiary) 100%
    );
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s ease-in-out infinite;
    border-radius: var(--radius-md);
}

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

/* Modern Scrollbar */
::-webkit-scrollbar {
    width: 6px;
    height: 6px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background-color: var(--color-border);
    border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
    background-color: var(--color-text-tertiary);
}

/* Interactive States */
.interactive {
    position: relative;
    overflow: hidden;
}

.interactive::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    width: 0;
    height: 0;
    border-radius: var(--radius-full);
    background-color: rgba(0, 0, 0, 0.05);
    transform: translate(-50%, -50%);
    transition: width var(--transition-fast), height var(--transition-fast);
}

.interactive:active::before {
    width: 100%;
    height: 100%;
}

/* Responsive Container */
.container-modern {
    width: 100%;
    max-width: 640px;
    margin: 0 auto;
    padding: 0 var(--space-lg);
}

@media (min-width: 768px) {
    .container-modern {
        padding: 0 var(--space-xl);
    }
}

/* Focus Visible - Accessibility */
*:focus-visible {
    outline: none;
}

/* Dark mode ready (for future) */
@media (prefers-color-scheme: dark) {
    /* Will be implemented later */
}