/* Skip link for accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary, #667eea);
    color: #fff;
    padding: 8px 16px;
    z-index: 10000;
    transition: top 0.2s;
    font-size: 14px;
    border-radius: 0 0 4px 0;
}
.skip-link:focus {
    top: 0;
}

:root {
    --primary: #667eea;
    --primary-dark: #5568d3;
    --accent: #FF6B35;
    --accent-dark: #e55a28;
    --background: #0f0f23;
    --surface: #1a1a3a;
    --surface-light: #2a2a4a;
    --text-primary: #ffffff;
    --text-secondary: #b0b0d0;
    --neon-green: #00ff88;
    --neon-purple: #d946ef;
    --neon-blue: #0ea5e9;
    --danger: #ef4444;
    --success: #10b981;

    --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition: 300ms cubic-bezier(0.4, 0, 0.2, 1);
    --transition-slow: 600ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* App Loader */
.app-loader {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: var(--background, #0f0f23);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 9999;
    transition: opacity 0.3s;
}
.app-loader.hidden {
    opacity: 0;
    pointer-events: none;
}
.loader-spinner {
    width: 40px; height: 40px;
    border: 3px solid rgba(255,255,255,0.1);
    border-top-color: #667eea;
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    -webkit-tap-highlight-color: transparent;
}

/* Touch Optimization */
button, a, input, [role="button"], [role="link"] {
    touch-action: manipulation;
    -webkit-user-select: none;
    user-select: none;
}

input[type="text"], textarea {
    -webkit-user-select: text;
    user-select: text;
}

html, body {
    width: 100%;
    height: 100%;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background-color: var(--background);
    color: var(--text-primary);
    overflow: hidden;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    -webkit-touch-callout: none;
}

body {
    display: flex;
    flex-direction: column;
}

/* Language Selector */
.language-selector {
    position: fixed;
    top: 10px;
    right: 10px;
    z-index: 1000;
}

.lang-toggle {
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: rgba(102, 126, 234, 0.2);
    border: 2px solid var(--primary);
    color: var(--primary);
    font-size: 20px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition-fast);
    backdrop-filter: blur(10px);
}

.lang-toggle:hover {
    background: rgba(102, 126, 234, 0.3);
    transform: scale(1.05);
}

.lang-toggle:active {
    transform: scale(0.95);
}

.lang-menu {
    position: absolute;
    top: 50px;
    right: 0;
    background: rgba(26, 26, 58, 0.95);
    border: 1px solid rgba(102, 126, 234, 0.3);
    border-radius: 8px;
    padding: 8px;
    backdrop-filter: blur(10px);
    display: flex;
    flex-direction: column;
    gap: 4px;
    min-width: 120px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.3);
}

.lang-menu.hidden {
    display: none;
}

.lang-option {
    padding: 8px 12px;
    background: transparent;
    border: none;
    color: var(--text-primary);
    text-align: left;
    cursor: pointer;
    border-radius: 4px;
    font-size: 12px;
    transition: all var(--transition-fast);
}

.lang-option:hover {
    background: rgba(102, 126, 234, 0.2);
    color: var(--neon-green);
}

/* Ad Containers */
.ad-container {
    background: rgba(26, 26, 58, 0.8);
    border-bottom: 1px solid rgba(102, 126, 234, 0.2);
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 90px;
    padding: 10px;
}

.ad-top {
    width: 100%;
    min-height: 90px;
}

.ad-interstitial {
    position: fixed;
    bottom: 20px;
    left: 50%;
    transform: translateX(-50%);
    background: rgba(26, 26, 58, 0.95);
    border: 1px solid rgba(102, 126, 234, 0.3);
    border-radius: 8px;
    backdrop-filter: blur(10px);
    padding: 10px;
    z-index: 100;
}

/* Game Wrapper */
.game-wrapper {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}

/* Screen System */
.screen {
    position: absolute;
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    opacity: 0;
    pointer-events: none;
    transition: opacity var(--transition);
}

.screen.active {
    opacity: 1;
    pointer-events: auto;
}

/* Start Screen */
.start-screen {
    background: linear-gradient(135deg, #0f0f23 0%, #1a0f3a 100%);
    z-index: 10;
}

.start-content {
    text-align: center;
    animation: slideUp 0.6s ease-out;
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.game-title {
    margin-bottom: 40px;
}

.game-title h1 {
    font-size: 48px;
    font-weight: 800;
    background: linear-gradient(45deg, var(--neon-green), var(--neon-blue), var(--neon-purple));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    text-shadow: 0 0 30px rgba(0, 255, 136, 0.3);
    letter-spacing: 2px;
    margin-bottom: 10px;
}

.subtitle {
    font-size: 18px;
    color: var(--neon-green);
    font-weight: 600;
    letter-spacing: 1px;
}

.bird-demo {
    width: 100px;
    height: 100px;
    margin: 0 auto 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(102, 126, 234, 0.1);
    border: 2px solid var(--primary);
    border-radius: 50%;
    animation: float 3s ease-in-out infinite;
}

@keyframes float {
    0%, 100% {
        transform: translateY(0px);
    }
    50% {
        transform: translateY(-10px);
    }
}

.bird-icon {
    width: 60px;
    height: 60px;
    filter: drop-shadow(0 0 10px rgba(0, 255, 136, 0.5));
}

.instructions {
    margin-bottom: 40px;
    max-width: 300px;
    margin-left: auto;
    margin-right: auto;
}

.instructions p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 12px;
    line-height: 1.6;
}

/* Buttons */
.btn {
    padding: 14px 32px;
    font-size: 16px;
    font-weight: 600;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    min-height: 44px;
    min-width: 44px;
}

.btn-primary {
    background: linear-gradient(45deg, var(--primary), var(--primary-dark));
    color: white;
    margin-bottom: 20px;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 20px rgba(102, 126, 234, 0.4);
}

.btn-primary:active {
    transform: translateY(0);
}

.btn-secondary {
    background: rgba(102, 126, 234, 0.2);
    color: var(--primary);
    border: 1px solid var(--primary);
    margin-bottom: 12px;
}

.btn-secondary:hover {
    background: rgba(102, 126, 234, 0.3);
    color: var(--neon-green);
    border-color: var(--neon-green);
}

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

.best-score {
    font-size: 14px;
    color: var(--text-secondary);
    margin-top: 20px;
}

.best-score span:last-child {
    color: var(--neon-green);
    font-weight: 700;
    margin-left: 8px;
}

/* Game Screen */
.game-screen {
    flex: 1;
    background: linear-gradient(180deg, #0f0f23 0%, #1a0f3a 100%);
    flex-direction: column;
    padding: 20px;
    z-index: 5;
}

.game-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 10px;
    padding: 0 10px;
    font-weight: 700;
}

.score-display, .level-display {
    font-size: 16px;
    color: var(--text-primary);
    display: flex;
    align-items: center;
    gap: 8px;
}

.score-display span:last-child, .level-display span:last-child {
    color: var(--neon-green);
    font-size: 20px;
    font-weight: 800;
}

#game-canvas {
    flex: 1;
    background: linear-gradient(to bottom,
        rgba(15, 15, 35, 0.9),
        rgba(26, 26, 58, 0.9)
    );
    border: 2px solid rgba(102, 126, 234, 0.2);
    border-radius: 8px;
    display: block;
    cursor: pointer;
    box-shadow: 0 0 30px rgba(102, 126, 234, 0.1);
}

.pause-indicator {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background: rgba(0, 0, 0, 0.8);
    color: var(--neon-purple);
    padding: 20px 40px;
    border-radius: 8px;
    font-size: 24px;
    font-weight: 800;
    letter-spacing: 2px;
    border: 2px solid var(--neon-purple);
    display: none;
    z-index: 50;
    pointer-events: none;
}

.pause-indicator.visible {
    display: block;
    animation: pulse 0.5s ease-in-out;
}

@keyframes pulse {
    0%, 100% {
        opacity: 1;
        transform: translate(-50%, -50%) scale(1);
    }
    50% {
        opacity: 0.7;
        transform: translate(-50%, -50%) scale(1.05);
    }
}

/* Game Over Screen */
.gameover-screen {
    background: linear-gradient(135deg, #0f0f23 0%, #1a0f3a 100%);
    z-index: 8;
}

.gameover-content {
    text-align: center;
    animation: slideUp 0.4s ease-out;
}

.gameover-content h2 {
    font-size: 40px;
    color: var(--danger);
    font-weight: 800;
    margin-bottom: 30px;
    text-shadow: 0 0 20px rgba(239, 68, 68, 0.3);
}

.score-summary {
    background: rgba(102, 126, 234, 0.1);
    border: 1px solid rgba(102, 126, 234, 0.3);
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    min-width: 250px;
}

.score-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 16px;
    margin-bottom: 12px;
    padding: 8px 0;
}

.score-item:last-child {
    margin-bottom: 0;
}

.score-item span:first-child {
    color: var(--text-secondary);
}

.score-item span:last-child {
    color: var(--neon-green);
    font-weight: 800;
    font-size: 18px;
}

.new-record {
    color: var(--accent);
    animation: pulse-record 0.6s ease-in-out;
}

@keyframes pulse-record {
    0%, 100% {
        opacity: 1;
        transform: scale(1);
    }
    50% {
        opacity: 0.7;
        transform: scale(1.1);
    }
}

.score-item.hidden {
    display: none;
}

.share-section {
    margin-bottom: 20px;
}

/* Utility Classes */
.hidden {
    display: none !important;
}

/* Responsive Design */
@media (max-width: 768px) {
    .game-title h1 {
        font-size: 36px;
    }

    .subtitle {
        font-size: 16px;
    }

    .bird-demo {
        width: 80px;
        height: 80px;
    }

    .instructions p {
        font-size: 13px;
    }

    .btn {
        padding: 12px 24px;
        font-size: 14px;
    }

    .gameover-content h2 {
        font-size: 32px;
    }

    .game-header {
        font-size: 14px;
    }

    .score-display span:last-child, .level-display span:last-child {
        font-size: 18px;
    }
}

@media (max-width: 480px) {
    .game-title h1 {
        font-size: 28px;
    }

    .subtitle {
        font-size: 14px;
    }

    .bird-demo {
        width: 70px;
        height: 70px;
        margin-bottom: 30px;
    }

    .instructions p {
        font-size: 12px;
    }

    .btn {
        padding: 10px 20px;
        font-size: 12px;
    }

    .gameover-content h2 {
        font-size: 24px;
    }

    .score-summary {
        min-width: 200px;
        padding: 16px;
    }

    .score-item {
        font-size: 14px;
    }

    .game-header {
        font-size: 12px;
    }

    .pause-indicator {
        font-size: 18px;
        padding: 15px 30px;
    }
}

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

/* Focus Styles for Keyboard Navigation */
.btn:focus,
.lang-option:focus,
.lang-toggle:focus {
    outline: 2px solid var(--neon-green);
    outline-offset: 2px;
}

/* Print Styles */
/* Scrollbar Styling */
::-webkit-scrollbar {
    width: 10px;
}

::-webkit-scrollbar-track {
    background: var(--bg-dark, var(--bg-primary, var(--background, #0f0f23)));
}

::-webkit-scrollbar-thumb {
    background: #e74c3c;
    border-radius: 5px;
    border: 2px solid var(--bg-dark, var(--bg-primary, var(--background, #0f0f23)));
}

::-webkit-scrollbar-thumb:hover {
    background: #eb6f63;
    opacity: 0.8;
}

/* Selection Color */
::selection {
    background: #e74c3c;
    color: white;
}

::-moz-selection {
    background: #e74c3c;
    color: white;
}

@media print {
    .ad-container,
    .language-selector {
        display: none;
    }
}

/* Light Mode */
[data-theme="light"] {
    --background: #f5f5fa;
    --surface: #ffffff;
    --surface-light: #f8f8fc;
    --text-primary: #1a1a2e;
    --text-secondary: #5a5a70;
}

[data-theme="light"] body {
    background-color: var(--background);
    color: var(--text-primary);
}

[data-theme="light"] .start-screen {
    background: linear-gradient(135deg, #f5f5fa 0%, #e8e8f0 100%);
}

[data-theme="light"] .lang-toggle {
    background: rgba(102, 126, 234, 0.1);
    border-color: rgba(102, 126, 234, 0.2);
    color: var(--primary);
}

[data-theme="light"] .lang-menu {
    background: rgba(255, 255, 255, 0.95);
    border-color: rgba(102, 126, 234, 0.2);
}

[data-theme="light"] .lang-option {
    color: var(--text-primary);
}

[data-theme="light"] .lang-option:hover {
    background: rgba(102, 126, 234, 0.1);
}

[data-theme="light"] .ad-container {
    background: rgba(102, 126, 234, 0.05);
    border-color: rgba(102, 126, 234, 0.1);
}

[data-theme="light"] .game-screen {
    background: linear-gradient(180deg, #f5f5fa 0%, #e8e8f0 100%);
}

[data-theme="light"] #game-canvas {
    background: linear-gradient(to bottom,
        rgba(245, 245, 250, 0.9),
        rgba(232, 232, 240, 0.9)
    );
    border-color: rgba(102, 126, 234, 0.15);
}

[data-theme="light"] .gameover-screen {
    background: linear-gradient(135deg, #f5f5fa 0%, #e8e8f0 100%);
}

[data-theme="light"] .score-summary {
    background: rgba(102, 126, 234, 0.05);
    border-color: rgba(102, 126, 234, 0.15);
}

[data-theme="light"] .btn-secondary {
    background: rgba(102, 126, 234, 0.1);
    border-color: rgba(102, 126, 234, 0.2);
    color: var(--primary);
}

[data-theme="light"] .btn-secondary:hover {
    background: rgba(102, 126, 234, 0.15);
}

/* Theme Toggle */
.theme-toggle {
    position: fixed;
    top: 12px;
    right: 56px;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 50%;
    width: 40px;
    height: 40px;
    font-size: 18px;
    cursor: pointer;
    transition: all 0.3s ease;
    display: flex;
    align-items: center;
    justify-content: center;
}

.theme-toggle:hover {
    background: rgba(255, 255, 255, 0.15);
}

.theme-toggle:active {
    transform: scale(0.95);
}

[data-theme="light"] .theme-toggle {
    background: rgba(102, 126, 234, 0.1);
    border-color: rgba(102, 126, 234, 0.2);
    color: var(--primary);
}

[data-theme="light"] .theme-toggle:hover {
    background: rgba(102, 126, 234, 0.15);
}

/* Focus Visible - Accessibility */
button:focus-visible,
a:focus-visible,
input:focus-visible,
[role="button"]:focus-visible {
    outline: 3px solid #667eea;
    outline-offset: 2px;
}