/* CSS Custom Properties for Theming */
:root {
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-card: #ffffff;
    --border-color: #e5e7eb;
    --text-primary: #111827;
    --text-secondary: #6b7280;
    --accent-color: #3b82f6;
    --accent-hover: #2563eb;
    --search-highlight: #fef08a;
    --header-bg: rgba(255, 255, 255, 0.8);
}

.dark {
    --bg-primary: #0f172a;
    --bg-secondary: #1e293b;
    --bg-card: #1e293b;
    --border-color: #334155;
    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;
    --accent-color: #60a5fa;
    --accent-hover: #3b82f6;
    --search-highlight: #854d0e;
    --header-bg: rgba(15, 23, 42, 0.8);
}

/* Base Styles */
body {
    background-color: var(--bg-primary);
    color: var(--text-primary);
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    line-height: 1.6;
}

/* Header Styles */
header {
    background-color: var(--header-bg);
    border-color: var(--border-color);
}

/* Card Styles */
.symbol-card {
    background-color: var(--bg-card);
    border-color: var(--border-color);
    transition: all 0.2s ease;
}

.symbol-card:hover {
    border-color: var(--accent-color);
    transform: translateY(-2px);
}

/* Section Content */
.section-content > div:not(.grid) {
    background-color: var(--bg-card);
}

/* Search Input */
#search-input {
    background-color: var(--bg-card);
    border-color: var(--border-color);
    color: var(--text-primary);
}

#search-input:focus {
    border-color: var(--accent-color);
    ring-color: var(--accent-color);
}

#search-input::placeholder {
    color: var(--text-secondary);
}

/* Copy Button */
.copy-btn {
    color: var(--text-secondary);
    transition: all 0.2s ease;
}

.copy-btn:hover {
    color: var(--accent-color);
    transform: scale(1.1);
}

.copy-btn.copy-success {
    color: #22c55e;
}

/* Copy Feedback Toast */
.copy-feedback {
    position: fixed;
    bottom: 2rem;
    right: 2rem;
    background-color: var(--text-primary);
    color: var(--bg-primary);
    padding: 0.75rem 1.5rem;
    border-radius: 0.5rem;
    box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
    opacity: 0;
    transform: translateY(1rem);
    transition: all 0.3s ease;
    pointer-events: none;
    z-index: 1000;
    font-weight: 500;
}

.copy-feedback.show {
    opacity: 1;
    transform: translateY(0);
}

/* Search Highlight */
.search-highlight,
mark {
    background-color: var(--search-highlight);
    color: var(--text-primary);
    padding: 0.125rem 0.25rem;
    border-radius: 0.25rem;
    font-weight: 600;
}

.dark .search-highlight,
.dark mark {
    background-color: var(--search-highlight);
    color: #fef3c7;
}

/* Navigation Links */
nav a {
    color: var(--text-primary);
    transition: all 0.2s ease;
}

nav a:hover {
    color: var(--accent-color);
}

/* Footer */
footer {
    background-color: var(--bg-secondary);
    border-color: var(--border-color);
    color: var(--text-secondary);
}

footer a {
    color: var(--accent-color);
    transition: color 0.2s ease;
}

footer a:hover {
    color: var(--accent-hover);
}

/* Theme Toggle Button */
#theme-toggle {
    transition: all 0.2s ease;
}

#theme-toggle:hover {
    transform: rotate(15deg);
}

/* Smooth Transitions */
* {
    transition-property: background-color, border-color, color;
    transition-duration: 200ms;
    transition-timing-function: ease-in-out;
}

/* Utility Classes */
.dark .opacity-80 {
    opacity: 0.7;
}

.dark .opacity-70 {
    opacity: 0.6;
}

.dark .opacity-60 {
    opacity: 0.5;
}

/* Responsive Typography */
@media (max-width: 640px) {
    h1 {
        font-size: 1.5rem;
    }
    
    h2 {
        font-size: 1.25rem;
    }
    
    .symbol-card {
        padding: 0.75rem;
    }
}

/* Focus Styles for Accessibility */
a:focus,
button:focus,
input:focus {
    outline: 2px solid var(--accent-color);
    outline-offset: 2px;
}

/* Print Styles */
@media print {
    header,
    nav,
    footer,
    #theme-toggle,
    .copy-btn {
        display: none;
    }
    
    body {
        background-color: white;
        color: black;
    }
    
    .symbol-card {
        break-inside: avoid;
        page-break-inside: avoid;
    }
}

/* Loading State (if needed) */
.loading {
    opacity: 0.5;
    pointer-events: none;
}

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

.symbol-card {
    animation: fadeIn 0.3s ease forwards;
}

/* Stagger animation for cards */
.symbol-card:nth-child(1) { animation-delay: 0.05s; }
.symbol-card:nth-child(2) { animation-delay: 0.1s; }
.symbol-card:nth-child(3) { animation-delay: 0.15s; }
.symbol-card:nth-child(4) { animation-delay: 0.2s; }
.symbol-card:nth-child(5) { animation-delay: 0.25s; }
.symbol-card:nth-child(6) { animation-delay: 0.3s; }

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 10px;
    height: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-secondary);
}

::-webkit-scrollbar-thumb {
    background: var(--border-color);
    border-radius: 5px;
}

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

.dark ::-webkit-scrollbar-track {
    background: var(--bg-primary);
}

.dark ::-webkit-scrollbar-thumb {
    background: var(--border-color);
}

.dark ::-webkit-scrollbar-thumb:hover {
    background: var(--text-secondary);
}

/* Skeleton Loading (future enhancement) */
.skeleton {
    background: linear-gradient(90deg, var(--bg-card) 25%, var(--bg-secondary) 50%, var(--bg-card) 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
}

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

/* Accessibility: Reduced Motion */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}