/* ====================================
   PONG GAME - GLOBAL STYLES
   ==================================== */

/* Skip link for accessibility */
.skip-link {
    position: absolute;
    top: -40px;
    left: 0;
    background: var(--primary, #e67e22);
    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 {
    color-scheme: dark;
    --primary-color: #e67e22;
    --bg-dark: #0f0f23;
    --bg-darker: #0a0a15;
    --text-primary: #ffffff;
    --text-secondary: #b8b8cc;
    --accent-neon: #00d4ff;
    --accent-glow: rgba(230, 126, 34, 0.5);
    --border-glow: 0 0 20px rgba(230, 126, 34, 0.3);
    --border-glow-strong: 0 0 30px rgba(230, 126, 34, 0.6);
}

/* App Loader */
.app-loader {
    position: fixed;
    top: 0; left: 0; right: 0; bottom: 0;
    background: var(--bg-dark, #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: #e67e22;
    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;
}

html, body {
    width: 100%;
    height: 100%;
    overflow: hidden;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background-color: var(--bg-dark);
    color: var(--text-primary);
}

/* ====================================
   MAIN CONTAINER & SCREENS
   ==================================== */

.app-container {
    width: 100%;
    height: 100vh;
    display: flex;
    flex-direction: column;
    background: linear-gradient(135deg, var(--bg-dark) 0%, var(--bg-darker) 100%);
    position: relative;
    overflow: hidden;
}

.screen {
    width: 100%;
    height: 100%;
    display: none;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    position: absolute;
    top: 0;
    left: 0;
    z-index: 10;
    background: linear-gradient(135deg, var(--bg-dark) 0%, var(--bg-darker) 100%);
}

.screen.active {
    display: flex;
    z-index: 20;
}

/* ====================================
   LANGUAGE SELECTOR
   ==================================== */

.language-selector {
    position: fixed;
    top: 15px;
    right: 15px;
    z-index: 100;
}

.lang-toggle {
    width: 44px;
    height: 44px;
    border: 2px solid var(--primary-color);
    border-radius: 50%;
    background: transparent;
    color: var(--primary-color);
    font-size: 20px;
    cursor: pointer;
    display: flex;
    justify-content: center;
    align-items: center;
    transition: all 0.3s ease;
    box-shadow: var(--border-glow);
}

.lang-toggle:hover, .lang-toggle:active {
    background: var(--accent-glow);
    transform: scale(1.1);
    box-shadow: var(--border-glow-strong);
}

.lang-menu {
    position: absolute;
    top: 60px;
    right: 0;
    background: var(--bg-darker);
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    padding: 8px;
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 8px;
    min-width: 200px;
    box-shadow: var(--border-glow-strong);
    max-height: 400px;
    overflow-y: auto;
}

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

.lang-option {
    padding: 10px;
    background: transparent;
    border: 1px solid var(--primary-color);
    border-radius: 4px;
    color: var(--text-primary);
    cursor: pointer;
    font-size: 12px;
    transition: all 0.2s ease;
    white-space: nowrap;
    min-height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.lang-option:hover, .lang-option:active {
    background: var(--accent-glow);
    border-color: var(--accent-neon);
    transform: translateY(-2px);
}

/* ====================================
   MENU SCREEN
   ==================================== */

#menu-screen {
    padding: 20px;
}

.menu-content {
    text-align: center;
    max-width: 500px;
    width: 100%;
}

.game-title {
    font-size: clamp(48px, 10vw, 80px);
    font-weight: 900;
    letter-spacing: 6px;
    background: linear-gradient(45deg, var(--primary-color), var(--accent-neon));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 10px;
    text-shadow: 0 0 30px var(--accent-glow);
    animation: glow-pulse 2s ease-in-out infinite;
}

@keyframes glow-pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.8; }
}

.game-subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 40px;
    letter-spacing: 2px;
}

.menu-buttons {
    display: flex;
    flex-direction: column;
    gap: 15px;
    margin-bottom: 30px;
}

.menu-btn {
    padding: 16px 32px;
    font-size: 16px;
    font-weight: 600;
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    background: transparent;
    color: var(--primary-color);
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
    min-height: 44px;
    position: relative;
    overflow: hidden;
}

.menu-btn::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: var(--accent-glow);
    transition: left 0.3s ease;
    z-index: -1;
}

.menu-btn:hover::before, .menu-btn:active::before {
    left: 0;
}

.menu-btn:hover, .menu-btn:active {
    background: var(--accent-glow);
    box-shadow: var(--border-glow-strong), inset 0 0 20px var(--accent-glow);
    transform: translateY(-2px);
}

.menu-btn.danger {
    border-color: #e74c3c;
    color: #e74c3c;
}

.menu-btn.danger::before {
    background: rgba(231, 76, 60, 0.3);
}

/* ====================================
   BUTTON SYSTEM (.btn variants)
   ==================================== */

.btn {
    padding: 16px 32px;
    font-size: 16px;
    font-weight: 600;
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    background: transparent;
    color: var(--primary-color);
    cursor: pointer;
    transition: all 0.3s ease;
    text-transform: uppercase;
    letter-spacing: 1px;
    min-height: 44px;
    position: relative;
    overflow: hidden;
    display: block;
    width: 100%;
    text-align: center;
}

.btn:hover, .btn:active {
    transform: translateY(-2px);
    box-shadow: var(--border-glow-strong);
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), #d35400);
    color: #fff;
    border-color: var(--primary-color);
    box-shadow: var(--border-glow);
}

.btn-primary:hover, .btn-primary:active {
    background: linear-gradient(135deg, #d35400, var(--primary-color));
    box-shadow: var(--border-glow-strong), inset 0 0 20px rgba(255,255,255,0.1);
}

.btn-secondary {
    background: rgba(230, 126, 34, 0.15);
    color: var(--primary-color);
}

.btn-secondary:hover, .btn-secondary:active {
    background: var(--accent-glow);
    box-shadow: var(--border-glow);
}

.btn-outline {
    background: transparent;
    color: var(--text-secondary);
    border-color: rgba(230, 126, 34, 0.4);
}

.btn-outline:hover, .btn-outline:active {
    background: rgba(230, 126, 34, 0.1);
    color: var(--primary-color);
    border-color: var(--primary-color);
}

.btn-icon {
    width: 36px;
    height: 36px;
    border: 1.5px solid rgba(230, 126, 34, 0.5);
    border-radius: 8px;
    background: rgba(230, 126, 34, 0.1);
    color: var(--primary-color);
    font-size: 16px;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s ease;
    padding: 0;
}

.btn-icon:hover, .btn-icon:active {
    background: var(--accent-glow);
    border-color: var(--primary-color);
    box-shadow: var(--border-glow);
    transform: scale(1.1);
}

/* ====================================
   HELP SCREEN
   ==================================== */

.help-content {
    background: rgba(10, 10, 21, 0.8);
    backdrop-filter: blur(10px);
    border: 2px solid var(--primary-color);
    border-radius: 12px;
    padding: 30px;
    max-width: 440px;
    width: 90%;
    box-shadow: var(--border-glow-strong);
    animation: fadeIn 0.3s ease;
    max-height: 85vh;
    overflow-y: auto;
}

.help-content h2 {
    font-size: 24px;
    margin-bottom: 20px;
    color: var(--primary-color);
    text-align: center;
}

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

.help-section h3 {
    font-size: 15px;
    color: var(--accent-neon);
    margin-bottom: 10px;
    padding-bottom: 6px;
    border-bottom: 1px solid rgba(0, 212, 255, 0.2);
}

.help-section p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.help-controls {
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.help-control-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 8px 12px;
    background: rgba(230, 126, 34, 0.08);
    border-radius: 6px;
    font-size: 13px;
}

.help-key {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 50px;
    padding: 4px 10px;
    background: rgba(230, 126, 34, 0.15);
    border: 1px solid rgba(230, 126, 34, 0.4);
    border-radius: 4px;
    font-family: monospace;
    font-weight: 700;
    color: var(--primary-color);
    font-size: 13px;
    white-space: nowrap;
}

.help-badge {
    font-size: 11px;
    font-weight: 700;
    padding: 2px 8px;
    border-radius: 4px;
    letter-spacing: 0.5px;
}

.help-badge.p1 {
    background: rgba(0, 212, 255, 0.2);
    color: var(--accent-neon);
    border: 1px solid rgba(0, 212, 255, 0.4);
}

.help-badge.p2 {
    background: rgba(230, 126, 34, 0.2);
    color: var(--primary-color);
    border: 1px solid rgba(230, 126, 34, 0.4);
}

/* ====================================
   SETTINGS & STATS SCREENS
   ==================================== */

.settings-content, .stats-content {
    background: rgba(10, 10, 21, 0.8);
    backdrop-filter: blur(10px);
    border: 2px solid var(--primary-color);
    border-radius: 12px;
    padding: 30px;
    max-width: 400px;
    width: 90%;
    box-shadow: var(--border-glow-strong);
}

.settings-content h2, .stats-content h2 {
    font-size: 28px;
    margin-bottom: 30px;
    color: var(--primary-color);
}

.setting-group {
    margin-bottom: 20px;
    text-align: left;
}

.setting-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 500;
    color: var(--text-primary);
    cursor: pointer;
    font-size: 14px;
}

.setting-group input[type="checkbox"] {
    width: 20px;
    height: 20px;
    cursor: pointer;
    margin-right: 8px;
    accent-color: var(--primary-color);
}

.difficulty-buttons {
    display: flex;
    gap: 10px;
    margin-top: 8px;
}

.difficulty-btn {
    flex: 1;
    padding: 10px;
    border: 2px solid var(--primary-color);
    border-radius: 6px;
    background: transparent;
    color: var(--primary-color);
    cursor: pointer;
    font-size: 12px;
    font-weight: 600;
    transition: all 0.2s ease;
    min-height: 44px;
}

.difficulty-btn.active {
    background: var(--accent-glow);
    box-shadow: var(--border-glow);
}

.difficulty-btn:hover, .difficulty-btn:active {
    transform: translateY(-2px);
    box-shadow: var(--border-glow);
}

#paddle-size {
    width: 100%;
    height: 6px;
    margin: 10px 0;
    border-radius: 3px;
    background: var(--bg-darker);
    outline: none;
    -webkit-appearance: none;
    appearance: none;
}

#paddle-size::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    box-shadow: var(--border-glow);
}

#paddle-size::-moz-range-thumb {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
    border: none;
    box-shadow: var(--border-glow);
}

#paddle-size-display {
    display: block;
    text-align: right;
    font-size: 12px;
    color: var(--text-secondary);
    margin-top: 5px;
}

/* ====================================
   STATS SCREEN
   ==================================== */

.stat-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px;
    background: rgba(230, 126, 34, 0.1);
    border: 1px solid var(--primary-color);
    border-radius: 6px;
    margin-bottom: 12px;
    font-size: 14px;
}

.stat-value {
    font-size: 18px;
    font-weight: 700;
    color: var(--primary-color);
}

/* ====================================
   GAME SCREEN
   ==================================== */

#game-screen {
    justify-content: flex-start;
    padding: 0;
}

.game-header {
    width: 100%;
    padding: 12px 20px;
    background: rgba(10, 10, 21, 0.8);
    border-bottom: 2px solid var(--primary-color);
    backdrop-filter: blur(10px);
    z-index: 30;
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 10px;
}

.player-info {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    min-width: 70px;
}

.player-name,
.player-info > span:first-child {
    font-size: 11px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.score {
    font-size: 32px;
    font-weight: 900;
    color: var(--primary-color);
    text-shadow: 0 0 20px var(--accent-glow);
    min-width: 40px;
    text-align: center;
    line-height: 1;
}

.game-info {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 6px;
}

#game-time {
    font-size: 18px;
    color: var(--accent-neon);
    font-weight: 600;
    letter-spacing: 1px;
    font-variant-numeric: tabular-nums;
}

.game-info .game-controls {
    display: flex;
    gap: 8px;
    align-items: center;
}

.canvas-container {
    flex: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    overflow: hidden;
    position: relative;
}

#game-canvas {
    display: block;
    max-width: 100%;
    max-height: 100%;
    background: radial-gradient(circle at 50% 50%, rgba(230, 126, 34, 0.05) 0%, transparent 70%);
    image-rendering: pixelated;
    image-rendering: crisp-edges;
    touch-action: none;
}

.particles-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 25;
    overflow: hidden;
}

/* Score summary in gameover */
.score-summary {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 12px;
    margin-bottom: 25px;
}

.score-item {
    background: rgba(230, 126, 34, 0.1);
    border: 1px solid rgba(230, 126, 34, 0.3);
    border-radius: 8px;
    padding: 15px 12px;
    display: flex;
    flex-direction: column;
    gap: 6px;
    text-align: center;
}

.score-item span:first-child {
    font-size: 11px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.score-item span:last-child {
    font-size: 22px;
    font-weight: 800;
    color: var(--primary-color);
}

/* 2P control hint */
.control-hint {
    background: rgba(0, 212, 255, 0.15);
    border: 1px solid rgba(0, 212, 255, 0.4);
    border-radius: 8px;
    padding: 10px 20px;
    font-size: 13px;
    color: var(--accent-neon);
    text-align: center;
    letter-spacing: 0.5px;
    animation: fadeIn 0.3s ease;
    width: 100%;
}

.control-hint.hidden {
    display: none;
}

/* ====================================
   PAUSE & GAMEOVER SCREENS
   ==================================== */

.pause-content, .gameover-content {
    background: rgba(10, 10, 21, 0.95);
    backdrop-filter: blur(10px);
    border: 3px solid var(--primary-color);
    border-radius: 12px;
    padding: 40px 30px;
    max-width: 450px;
    width: 90%;
    text-align: center;
    box-shadow: 0 0 60px var(--accent-glow);
}

.pause-content h2, .gameover-content h2 {
    font-size: 36px;
    margin-bottom: 30px;
    color: var(--primary-color);
    text-transform: uppercase;
    letter-spacing: 2px;
}

#gameover-message {
    font-size: 18px;
    color: var(--text-secondary);
    margin-bottom: 25px;
    min-height: 50px;
}

.gameover-stats {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 15px;
    margin-bottom: 30px;
}

.stat-box {
    background: rgba(230, 126, 34, 0.1);
    border: 2px solid var(--primary-color);
    border-radius: 8px;
    padding: 20px 15px;
    display: flex;
    flex-direction: column;
    gap: 8px;
}

.stat-box span:first-child {
    font-size: 12px;
    color: var(--text-secondary);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.stat-box span:last-child {
    font-size: 24px;
    font-weight: 900;
    color: var(--primary-color);
}

/* ====================================
   AD BANNERS
   ==================================== */

.ad-banner {
    background: rgba(0, 0, 0, 0.3);
    border: 1px solid var(--primary-color);
    border-radius: 4px;
    min-height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.ad-top {
    margin-bottom: 20px;
}

.ad-bottom {
    margin-top: auto;
    width: 100%;
}

.ad-interstitial {
    margin-top: 20px;
    min-height: 250px;
    width: 100%;
}

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

@media (max-width: 768px) {
    .game-title {
        font-size: 48px;
    }

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

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

    .score {
        font-size: 24px;
    }

    .game-header {
        padding: 10px 15px;
    }

    .gameover-stats, .score-summary {
        grid-template-columns: 1fr;
    }

    .lang-menu {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .game-title {
        font-size: 36px;
        letter-spacing: 3px;
    }

    .btn, .menu-btn {
        padding: 12px 20px;
        font-size: 13px;
    }

    .settings-content, .stats-content, .pause-content, .gameover-content {
        max-width: 95%;
        padding: 20px;
    }

    .score {
        font-size: 20px;
    }

    .player-name,
    .player-info > span:first-child {
        font-size: 10px;
    }

    .game-header {
        padding: 8px 10px;
        gap: 6px;
    }

    .btn-icon {
        width: 32px;
        height: 32px;
        font-size: 14px;
    }

    .ad-banner {
        min-height: 50px;
    }
}

/* ====================================
   ANIMATIONS
   ==================================== */

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

.menu-content, .settings-content, .pause-content, .gameover-content {
    animation: fadeIn 0.3s ease;
}

/* Particle effect for canvas collisions */
.particle {
    position: fixed;
    pointer-events: none;
    font-size: 20px;
}

@keyframes particle-burst {
    0% {
        opacity: 1;
        transform: translate(0, 0) scale(1);
    }
    100% {
        opacity: 0;
        transform: translate(var(--tx), var(--ty)) scale(0);
    }
}

.particle {
    animation: particle-burst 0.6s ease-out forwards;
}

/* Buttons inside overlay panels */
.pause-content .btn,
.gameover-content .btn {
    margin-top: 10px;
}

/* ====================================
   ACCESSIBILITY
   ==================================== */

button {
    cursor: pointer;
}

button:focus-visible {
    outline: 2px solid var(--accent-neon);
    outline-offset: 2px;
}

input[type="range"]:focus-visible {
    outline: 2px solid var(--accent-neon);
    outline-offset: 2px;
}

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

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

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

[data-theme="light"] .lang-menu {
    background: var(--bg-darker);
    border-color: rgba(230, 126, 34, 0.2);
}

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

[data-theme="light"] .lang-option:hover {
    background: rgba(230, 126, 34, 0.1);
}

[data-theme="light"] .menu-content,
[data-theme="light"] .settings-content,
[data-theme="light"] .pause-content,
[data-theme="light"] .gameover-content {
    background: rgba(255, 255, 255, 0.95);
    border-color: rgba(230, 126, 34, 0.3);
}

[data-theme="light"] .score-item,
[data-theme="light"] .stat-box {
    background: rgba(230, 126, 34, 0.05);
    border-color: rgba(230, 126, 34, 0.2);
}

[data-theme="light"] .ad-banner {
    background: rgba(230, 126, 34, 0.05);
    border-color: rgba(230, 126, 34, 0.15);
}

[data-theme="light"] #game-canvas {
    background: radial-gradient(circle at 50% 50%, rgba(230, 126, 34, 0.03) 0%, transparent 70%);
}

/* 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(230, 126, 34, 0.1);
    border-color: rgba(230, 126, 34, 0.2);
    color: var(--text-primary);
}

[data-theme="light"] .theme-toggle:hover {
    background: rgba(230, 126, 34, 0.15);
}

/* Dark mode is always active (dark-first design) */

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