/* ============================================
   ENCYCLOPEDIA UNIVERSALIS - DESIGN SYSTEM
   Premium Black & White Aesthetic
   ============================================ */

/* CSS Variables */
:root {
    /* Colors */
    --color-bg: #f8f9fa;
    --color-surface: #ffffff;
    --color-surface-elevated: #ffffff;
    --color-text-primary: #202124;
    --color-text-secondary: #5f6368;
    --color-text-tertiary: #80868b;
    --color-border: #dadce0;
    --color-border-light: #e8eaed;

    /* Accent Colors for Category Dots */
    --color-science: #1a73e8;
    --color-history: #e91e63;
    --color-technology: #7c3aed;
    --color-arts: #fbbc04;
    --color-philosophy: #34a853;
    --color-geography: #e37400;
    --color-default: #1a73e8;

    /* Spacing */
    --spacing-xs: 0.25rem;
    --spacing-sm: 0.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
    --spacing-2xl: 3rem;

    /* Typography */
    --font-primary: 'Roboto', 'Google Sans', sans-serif;
    --font-display: 'Google Sans', 'Roboto', sans-serif;

    --text-xs: 0.75rem;
    --text-sm: 0.875rem;
    --text-base: 1rem;
    --text-lg: 1.125rem;
    --text-xl: 1.25rem;
    --text-2xl: 1.5rem;
    --text-3xl: 2rem;
    --text-4xl: 2.5rem;

    /* Effects */
    --radius-sm: 0.5rem;
    --radius-md: 0.75rem;
    --radius-lg: 1rem;
    --radius-xl: 1.5rem;
    --radius-full: 9999px;

    --shadow-sm: 0 1px 2px 0 rgba(60, 64, 67, 0.3);
    --shadow-md: 0 4px 6px -1px rgba(60, 64, 67, 0.15), 0 2px 4px -1px rgba(60, 64, 67, 0.1);
    --shadow-lg: 0 10px 15px -3px rgba(60, 64, 67, 0.1), 0 4px 6px -2px rgba(60, 64, 67, 0.05);
    --shadow-xl: 0 20px 25px -5px rgba(60, 64, 67, 0.1), 0 10px 10px -5px rgba(60, 64, 67, 0.04);
    --shadow-glow: 0 0 20px rgba(26, 115, 232, 0.2);

    /* Transitions */
    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-base: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 500ms cubic-bezier(0.4, 0, 0.2, 1);

    /* Glassmorphism */
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(0, 0, 0, 0.08);
}

/* Reset & Base Styles */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-primary);
    background: var(--color-bg);
    color: var(--color-text-primary);
    overflow: hidden;
    line-height: 1.6;
}

/* ============================================
   LOADING SCREEN
   ============================================ */

.loading-screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: var(--color-bg);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 10000;
    transition: opacity var(--transition-slow), visibility var(--transition-slow);
}

.loading-screen.hidden {
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
}

.loading-content {
    text-align: center;
}

.loading-planet {
    width: 80px;
    height: 80px;
    margin: 0 auto var(--spacing-xl);
    border-radius: 50%;
    background: radial-gradient(circle at 30% 30%, rgba(0, 0, 0, 0.12), transparent 70%),
        linear-gradient(to bottom, var(--color-surface-elevated), var(--color-surface));
    border: 2px solid var(--color-border);
    position: relative;
    animation: rotate 3s linear infinite;
    box-shadow: 0 0 40px rgba(0, 0, 0, 0.08);
}

.loading-planet::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 60%;
    height: 60%;
    border-radius: 50%;
    background: radial-gradient(circle, rgba(26, 115, 232, 0.4), transparent);
    animation: pulse 2s ease-in-out infinite;
}

@keyframes rotate {
    from {
        transform: rotate(0deg);
    }

    to {
        transform: rotate(360deg);
    }
}

@keyframes pulse {

    0%,
    100% {
        opacity: 0.5;
        transform: translate(-50%, -50%) scale(0.8);
    }

    50% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }
}

.loading-text {
    font-family: var(--font-display);
    font-size: var(--text-2xl);
    font-weight: 600;
    margin-bottom: var(--spacing-lg);
    background: linear-gradient(90deg, var(--color-text-primary), var(--color-text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.loading-bar {
    width: 300px;
    height: 4px;
    background: var(--color-surface);
    border-radius: var(--radius-full);
    overflow: hidden;
    margin: 0 auto;
}

.loading-progress {
    height: 100%;
    background: linear-gradient(90deg, var(--color-science), var(--color-technology));
    border-radius: var(--radius-full);
    animation: progress 2s ease-in-out infinite;
}

@keyframes progress {
    0% {
        width: 0%;
    }

    50% {
        width: 70%;
    }

    100% {
        width: 100%;
    }
}

/* ============================================
   MAIN APPLICATION
   ============================================ */

.app {
    width: 100vw;
    height: 100vh;
    /* Use dynamic viewport height for mobile browsers */
    height: 100dvh;
    position: relative;
    overflow: hidden;
}

.planet-canvas {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    cursor: grab;
}

.planet-canvas:active {
    cursor: grabbing;
}

/* ============================================
   UI OVERLAY
   ============================================ */

.ui-overlay {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    padding: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-lg);
}

.ui-overlay>* {
    pointer-events: auto;
}

/* Header */
.header {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg) var(--spacing-xl);
    box-shadow: var(--shadow-lg);
}

.header-content {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--spacing-xl);
}

.logo {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    font-family: var(--font-display);
    font-size: var(--text-xl);
    font-weight: 700;
    margin: 0;
}

.logo-icon {
    font-size: var(--text-3xl);
    animation: rotate 10s linear infinite;
}

.logo-text {
    background: linear-gradient(135deg, var(--color-text-primary), var(--color-text-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header-stats {
    display: flex;
    gap: var(--spacing-xl);
}

.stat {
    display: flex;
    flex-direction: column;
    align-items: flex-end;
}

.stat-value {
    font-size: var(--text-2xl);
    font-weight: 700;
    line-height: 1;
    margin-bottom: var(--spacing-xs);
}

.stat-label {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Search */
.search-container {
    position: relative;
    max-width: 600px;
    margin: 0 auto;
    width: 100%;
}

.search-box {
    position: relative;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-xl);
    padding: var(--spacing-md) var(--spacing-lg);
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    box-shadow: var(--shadow-lg);
    transition: all var(--transition-base);
}

.search-box:focus-within {
    border-color: rgba(26, 115, 232, 0.4);
    box-shadow: var(--shadow-xl), var(--shadow-glow);
}

.search-icon {
    color: var(--color-text-secondary);
    flex-shrink: 0;
}

.search-input {
    flex: 1;
    background: none;
    border: none;
    outline: none;
    font-family: var(--font-primary);
    font-size: var(--text-lg);
    color: var(--color-text-primary);
}

.search-input::placeholder {
    color: var(--color-text-tertiary);
}

.search-clear {
    background: rgba(0, 0, 0, 0.05);
    border: 1px solid rgba(0, 0, 0, 0.05);
    border-radius: 50%;
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: 1.2rem;
    color: var(--color-text-secondary);
    transition: all var(--transition-fast);
    flex-shrink: 0;
}

.search-clear:hover {
    background: rgba(0, 0, 0, 0.1);
    color: var(--color-text-primary);
    transform: rotate(90deg);
}

.search-results {
    position: absolute;
    top: calc(100% + var(--spacing-sm));
    left: 0;
    right: 0;
    background: rgba(255, 255, 255, 0.9);
    backdrop-filter: blur(30px) saturate(160%);
    -webkit-backdrop-filter: blur(30px) saturate(160%);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    max-height: 480px;
    overflow-y: auto;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.12);
    z-index: 100;
    animation: slideUp 0.3s cubic-bezier(0.16, 1, 0.3, 1);
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(10px);
    }

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.search-results.hidden {
    display: none;
}

.search-result-item {
    padding: var(--spacing-lg);
    border-bottom: 1px solid rgba(0, 0, 0, 0.05);
    cursor: pointer;
    transition: all var(--transition-fast);
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.search-result-item:hover {
    background: rgba(26, 115, 232, 0.04);
}

.search-result-item:active {
    background: rgba(26, 115, 232, 0.08);
    transform: scale(0.995);
}

.search-result-item:last-child {
    border-bottom: none;
}

.search-result-title {
    font-weight: 600;
    margin-bottom: var(--spacing-xs);
    color: var(--color-text-primary);
}

.search-result-snippet {
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
    display: -webkit-box;
    -webkit-line-clamp: 2;
    -webkit-box-orient: vertical;
    overflow: hidden;
}

.search-result-category {
    display: inline-block;
    font-size: var(--text-xs);
    padding: var(--spacing-xs) var(--spacing-sm);
    border-radius: var(--radius-sm);
    margin-top: var(--spacing-xs);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Category Filter */
.category-filter {
    display: flex;
    gap: var(--spacing-sm);
    justify-content: center;
    flex-wrap: wrap;
}

.category-btn {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    padding: var(--spacing-sm) var(--spacing-lg);
    font-family: var(--font-primary);
    font-size: var(--text-sm);
    font-weight: 500;
    color: var(--color-text-secondary);
    cursor: pointer;
    transition: all var(--transition-base);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

.category-btn:hover {
    border-color: rgba(26, 115, 232, 0.4);
    color: var(--color-text-primary);
    transform: translateY(-2px);
}

.category-btn.active {
    background: var(--color-text-primary);
    color: var(--color-bg);
    border-color: var(--color-text-primary);
    box-shadow: var(--shadow-glow);
}

/* Planet Controls */
.planet-controls {
    position: absolute;
    bottom: var(--spacing-lg);
    right: var(--spacing-lg);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.control-btn {
    width: 48px;
    height: 48px;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    color: var(--color-text-secondary);
    transition: all var(--transition-base);
    box-shadow: var(--shadow-md);
}

.control-btn:hover {
    border-color: rgba(26, 115, 232, 0.4);
    color: var(--color-text-primary);
    transform: scale(1.05);
}

.control-btn:active {
    transform: scale(0.95);
}

/* Instructions */
.instructions {
    position: absolute;
    bottom: var(--spacing-lg);
    left: 50%;
    transform: translateX(-50%);
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-full);
    padding: var(--spacing-sm) var(--spacing-xl);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}

/* ============================================
   ARTICLE PANEL
   ============================================ */

.article-panel {
    position: absolute;
    top: 0;
    right: 0;
    width: 100%;
    max-width: 600px;
    height: 100%;
    background: var(--glass-bg);
    backdrop-filter: blur(30px);
    border-left: 1px solid var(--glass-border);
    box-shadow: var(--shadow-xl);
    transform: translateX(100%);
    transition: transform var(--transition-slow);
    z-index: 1000;
    overflow: hidden;
}

.article-panel:not(.hidden) {
    transform: translateX(0);
}

.article-panel-content {
    height: 100%;
    overflow-y: auto;
    padding: var(--spacing-2xl);
    position: relative;
}

.panel-close {
    position: absolute;
    top: var(--spacing-lg);
    right: var(--spacing-lg);
    width: 40px;
    height: 40px;
    background: var(--color-surface-elevated);
    border: 1px solid var(--color-border);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    font-size: var(--text-3xl);
    color: var(--color-text-secondary);
    transition: all var(--transition-fast);
    z-index: 10;
}

.panel-close:hover {
    background: var(--color-surface);
    color: var(--color-text-primary);
    transform: rotate(90deg);
}

.article-header {
    margin-bottom: var(--spacing-xl);
}

.article-category-badge {
    display: inline-block;
    padding: var(--spacing-xs) var(--spacing-md);
    border-radius: var(--radius-sm);
    font-size: var(--text-xs);
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: var(--spacing-md);
}

.article-title {
    font-family: var(--font-display);
    font-size: var(--text-3xl);
    font-weight: 700;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

.article-meta {
    display: flex;
    gap: var(--spacing-md);
    font-size: var(--text-sm);
    color: var(--color-text-secondary);
}

.article-source {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
}

.article-body {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xl);
}

.article-section {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-lg);
}

.section-title {
    display: flex;
    align-items: center;
    gap: var(--spacing-sm);
    font-size: var(--text-lg);
    font-weight: 600;
    margin-bottom: var(--spacing-md);
    color: var(--color-text-primary);
}

.section-icon {
    color: var(--color-text-secondary);
}

.article-summary,
.article-content {
    font-size: var(--text-base);
    line-height: 1.8;
    color: var(--color-text-secondary);
}

.article-content p {
    margin-bottom: var(--spacing-md);
}

.summary-loading {
    display: flex;
    align-items: center;
    gap: var(--spacing-md);
    color: var(--color-text-tertiary);
}

.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-text-primary);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

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

.article-actions {
    display: flex;
    gap: var(--spacing-md);
    margin-top: var(--spacing-lg);
}

.action-btn {
    flex: 1;
    padding: var(--spacing-md) var(--spacing-lg);
    border-radius: var(--radius-md);
    font-family: var(--font-primary);
    font-size: var(--text-base);
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-base);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--spacing-sm);
    text-decoration: none;
}

.action-btn.primary {
    background: var(--color-text-primary);
    color: var(--color-bg);
    border: 1px solid var(--color-text-primary);
}

.action-btn.primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.action-btn.secondary {
    background: transparent;
    color: var(--color-text-primary);
    border: 1px solid var(--color-border);
}

.action-btn.secondary:hover {
    background: var(--color-surface-elevated);
    border-color: var(--color-text-primary);
}

/* ============================================
   TOAST NOTIFICATIONS
   ============================================ */

.toast-container {
    position: fixed;
    bottom: var(--spacing-lg);
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
    z-index: 10000;
    pointer-events: none;
}

.toast {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-md) var(--spacing-xl);
    box-shadow: var(--shadow-xl);
    font-size: var(--text-sm);
    animation: slideUp var(--transition-base);
    pointer-events: auto;
}

.toast.success {
    border-left: 3px solid var(--color-science);
}

.toast.error {
    border-left: 3px solid #ef4444;
}

.toast.info {
    border-left: 3px solid var(--color-technology);
}

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

    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* ============================================
   UTILITY CLASSES
   ============================================ */

.hidden {
    display: none !important;
}

/* Category Color Classes */
.category-science {
    background-color: var(--color-science);
    color: var(--color-bg);
}

.category-history {
    background-color: var(--color-history);
    color: var(--color-bg);
}

.category-technology {
    background-color: var(--color-technology);
    color: var(--color-bg);
}

.category-arts {
    background-color: var(--color-arts);
    color: var(--color-bg);
}

.category-philosophy {
    background-color: var(--color-philosophy);
    color: var(--color-bg);
}

.category-geography {
    background-color: var(--color-geography);
    color: var(--color-bg);
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

@media (max-width: 768px) {
    .ui-overlay {
        padding: var(--spacing-md);
        gap: var(--spacing-md);
    }

    .header {
        padding: var(--spacing-md);
    }

    .header-content {
        flex-direction: column;
        align-items: flex-start;
        gap: var(--spacing-md);
    }

    .logo {
        font-size: var(--text-lg);
    }

    .header-stats {
        width: 100%;
        justify-content: space-around;
    }

    .search-input {
        font-size: var(--text-base);
    }

    .category-filter {
        overflow-x: auto;
        justify-content: flex-start;
        -webkit-overflow-scrolling: touch;
    }

    .article-panel {
        max-width: 100%;
    }

    .article-panel-content {
        padding: var(--spacing-xl) var(--spacing-lg);
    }

    .article-title {
        font-size: var(--text-2xl);
    }

    .instructions {
        display: none;
    }

    .planet-controls {
        bottom: calc(var(--spacing-xl) + 24px);
        /* Lift significantly above mobile browser bars */
        right: var(--spacing-md);
    }
}

/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: var(--color-surface);
}

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

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