body {
            margin: 0;
            overflow: hidden;
            font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
            touch-action: none; /* Prevent default touch actions like scroll/zoom */
            background-color: #000; /* Ensure black background on load */
        }

        #gameCanvas {
            display: block;
            cursor: pointer;
        }

        #ui {
            position: absolute;
            top: 20px;
            left: 20px;
            color: white;
            font-size: 24px;
            text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.8); /* Increased shadow visibility */
            user-select: none;
            display: none; /* Hidden initially */
            z-index: 6; /* Ensure UI is above overlay */
        }

        .screen-overlay {
            position: absolute;
            inset: 0; /* Replaces top/left/width/height: 0/100% */
            background: linear-gradient(to bottom right, #111, #000);
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            z-index: 10;
            color: #ffffff;
            text-align: center;
            padding: 20px;
            box-sizing: border-box;
            animation: fadeIn 1s ease-in-out;
            transition: opacity 0.5s ease-out; /* For smooth hiding */
        }

        .screen-overlay.hidden { /* Class to fade out overlays */
             opacity: 0;
             pointer-events: none; /* Disable interaction when hidden */
        }


        .screen-overlay h1 {
            font-size: clamp(2.5rem, 6vw, 4.5rem);
            margin-bottom: 1rem;
            letter-spacing: 2px;
            text-transform: uppercase;
            text-shadow: 3px 3px 10px rgba(255, 0, 0, 0.8);
        }

        .screen-overlay p {
            font-size: clamp(1rem, 2.2vw, 1.5rem);
            margin-bottom: 2rem;
            max-width: 90%;
            line-height: 1.7;
        }

        .branding {
            font-size: clamp(0.9rem, 1.2vw, 1.1rem);
            color: #cccccc;
            margin-bottom: 2rem;
            font-style: italic;
            text-shadow: 1px 1px 5px rgba(255, 255, 255, 0.2);
        }

        button {
            border: none;
            color: white;
            padding: 12px 28px;
            font-size: 1.2rem;
            margin: 8px;
            cursor: pointer;
            border-radius: 12px;
            background-color: #333;
            transition: background-color 0.3s ease, transform 0.2s ease, box-shadow 0.2s ease;
            box-shadow: 0 4px 10px rgba(0, 0, 0, 0.3);
            user-select: none; /* Prevent text selection on buttons */
        }

        button:hover {
            transform: scale(1.07);
            box-shadow: 0 6px 14px rgba(0, 0, 0, 0.5);
        }

        button:active {
            transform: scale(1.02); /* Add active state feedback */
        }

        #startButton { background-color: #4CAF50; }
        #restartButtonGameOver,
        #restartButtonPause { background-color: #f44336; }
        #resumeButton { background-color: #2196F3; }
        #viewToggleButton { background-color: #9c27b0; }

        /* Style adjustments for smaller screens */
        @media (max-width: 768px) {
            .screen-overlay p {
                font-size: 1rem; /* Slightly smaller text */
            }
            button {
                font-size: 1rem;
                padding: 10px 20px;
            }
            #ui { font-size: 18px; } /* Smaller UI text */
             #minimap {
                 width: 100px !important; /* Force minimap size */
                 height: 100px !important;
             }
            #startScreen h1 {
                 font-size: clamp(2.5rem, 8vw, 4rem);
             }
             #startButton {
                 padding: 12px 30px;
                 font-size: 1.2rem;
             }
             /* Hide desktop instructions on mobile */
             #startScreen #desktop-instructions { display: none; }
        }

         /* Show mobile instructions only if touch is likely */
        @media (hover: none) and (pointer: coarse) {
            #startScreen #mobile-instructions { display: block; }
            #startScreen #desktop-instructions { display: none; } /* Ensure desktop hidden */
        }
        /* Default: show desktop, hide mobile */
        #startScreen #mobile-instructions { display: none; }

        .instructions-box {
            background: rgba(255, 255, 255, 0.04);
            border: 1px solid rgba(255, 255, 255, 0.1);
            border-left: 4px solid #f44336;
            border-radius: 12px;
            padding: 20px 30px;
            max-width: 580px;
            text-align: left;
            margin-bottom: 30px;
            line-height: 1.6;
            font-size: 0.95rem;
            color: #ccd;
        }

        .instructions-box key {
            background: rgba(244, 67, 54, 0.15);
            color: #f44336;
            padding: 2px 8px;
            border-radius: 4px;
            border: 1px solid rgba(244, 67, 54, 0.3);
            font-weight: bold;
        }


        #startScreen, #gameOver, #pauseScreen {
            position: absolute;
            top: 0;
            left: 0;
            width: 100%;
            height: 100%;
            background-color: rgba(0, 0, 0, 0.8); /* Slightly more opaque background */
            display: flex;
            flex-direction: column;
            justify-content: center;
            align-items: center;
            z-index: 10;
            color: white;
            text-align: center;
        }

        /* Enhanced Start Screen */
        #startScreen {
            background: radial-gradient(circle at center, #300, #000);
            overflow: hidden; /* Hide overflow from pseudo-elements */
            position: relative;
        }

        #startScreen::before {
            content: '';
            position: absolute;
            top: 0; left: 0; right: 0; bottom: 0;
            /* Subtle pattern background */
            background: url('data:image/svg+xml;utf8,<svg xmlns="http://www.w3.org/2000/svg" width="100" height="100" viewBox="0 0 100 100"><rect fill="none" width="100" height="100"/><path fill="rgba(255,0,0,0.02)" d="M0 0L100 100ZM100 0L0 100Z"/></svg>');
            opacity: 0.5;
            z-index: -1; /* Behind content */
            animation: subtlePatternShift 20s linear infinite; /* Slow movement */
        }

        #startScreen h1 {
            font-size: clamp(3rem, 10vw, 6rem);
            text-transform: uppercase;
            margin: 0 0 20px;
            letter-spacing: 4px;
            text-shadow:
                0 0 10px rgba(255,0,0,0.8),
                0 0 20px rgba(255,0,0,0.5),
                0 0 30px rgba(255,0,0,0.3),
                0 0 40px rgba(255,0,0,0.1);
            animation: pulse 4s infinite alternate;
            position: relative; /* Needed for ::after */
        }

        #startScreen h1::after {
            content: 'ZOMBIE SHOOTER';
            position: absolute;
            left: 50%; top: 50%;
            transform: translate(-50%, -50%);
            color: rgba(255,255,255,0.05); /* More subtle blur */
            z-index: -1;
            filter: blur(10px);
            font: inherit; /* Match parent font */
        }

        #startScreen .branding {
            font-size: calc(14px + 0.5vw);
            color: #e0dd2f; /* Brighter yellow */
            margin: 5px 0 25px;
            letter-spacing: 1px;
            position: relative;
            padding: 5px 15px;
            border-top: 1px solid rgba(255,255,255,0.1);
            border-bottom: 1px solid rgba(255,255,255,0.1);
        }

        #startScreen p.instructions {
            background-color: rgba(0,0,0,0.5); /* More contrast */
            padding: 20px;
            border-radius: 10px;
            box-shadow: 0 5px 15px rgba(0,0,0,0.5);
            max-width: min(600px, 90%);
            border-left: 4px solid #f44336; /* Thicker border */
            border-right: 4px solid #4CAF50;
            margin-bottom: 35px;
            line-height: 1.6; /* Improve readability */
        }

        #startScreen p.instructions b {
            color: #ff6666; /* Slightly softer red */
            text-shadow: 0 0 5px rgba(255,0,0,0.3);
        }

        #startButton {
            background: linear-gradient(to bottom, #5cb85c, #449d44);
            font-size: 1.5rem;
            text-transform: uppercase;
            letter-spacing: 2px;
            padding: 15px 40px;
            border-radius: 50px; /* Fully rounded */
            box-shadow:
                0 6px 0 #2d662d,
                0 6px 10px rgba(0,0,0,0.5);
            position: relative; /* Needed for ::after */
            overflow: hidden; /* Hide sheen overflow */
        }

        #startButton:hover {
            background: linear-gradient(to bottom, #6cd96c, #49a549); /* Brighter hover */
            transform: translateY(2px) scale(1.07); /* Combine transforms */
            box-shadow:
                0 4px 0 #2d662d,
                0 4px 6px rgba(0,0,0,0.5);
        }

        #startButton:active {
            transform: translateY(6px) scale(1.02); /* Combine active transforms */
            box-shadow: 0 0 0 #2d662d;
        }

        #startButton::after { /* Sheen effect */
            content: '';
            position: absolute;
            top: -50%; left: -50%;
            width: 200%; height: 200%;
            background: linear-gradient(to right, transparent, rgba(255,255,255,0.15), transparent);
            transform: rotate(45deg);
            animation: sheen 3s infinite;
        }

        /* Standard Screen Titles */
        #gameOver h1, #pauseScreen h1 {
            font-size: clamp(2.5rem, 6vw, 4rem); /* Responsive title size */
            margin-bottom: 20px;
        }
        #gameOver p, #pauseScreen p {
            font-size: clamp(1rem, 2vw, 1.3rem); /* Responsive text size */
            margin-bottom: 30px;
            max-width: 80%;
        }

        #gameOver { display: none; }
        #pauseScreen { display: none; }

        #crosshair {
            position: absolute;
            top: 50%;
            left: 50%;
            width: 20px;
            height: 20px;
            pointer-events: none;
            display: none; /* Controlled by JS */
            z-index: 5;
            transform: translate(-50%, -50%);
        }

        #crosshair::before, #crosshair::after {
            content: '';
            position: absolute;
            background-color: rgba(255, 255, 255, 0.85); /* Slightly more opaque */
            box-shadow: 0 0 3px rgba(0, 0, 0, 0.5); /* Subtle shadow for definition */
        }
        /* Thinner crosshair lines */
        #crosshair::before {
            width: 100%;
            height: 1.5px;
            top: 50%; left: 0;
            transform: translateY(-50%);
        }
        #crosshair::after {
            width: 1.5px;
            height: 100%;
            top: 0; left: 50%;
            transform: translateX(-50%);
        }

        #touchControls {
            position: absolute;
            bottom: 20px; /* Closer to bottom edge */
            width: 100%;
            display: none; /* Controlled by JS */
            justify-content: space-between;
            padding: 0 20px;
            box-sizing: border-box;
            z-index: 5;
            pointer-events: none; /* Container doesn't block clicks */
        }

        .joystick, #shootButtonTouch, #viewToggleTouchButton {
            width: 100px; height: 100px;
            background-color: rgba(200, 200, 200, 0.25); /* Lighter, less intrusive */
            border-radius: 50%;
            display: flex;
            justify-content: center;
            align-items: center;
            color: rgba(255, 255, 255, 0.7); /* Dimmer text */
            font-size: 16px;
            font-weight: bold;
            user-select: none;
            touch-action: none;
            pointer-events: auto; /* Buttons are interactive */
            position: relative;
            border: 1px solid rgba(255, 255, 255, 0.2); /* Subtle border */
        }

        .joystick-thumb {
            position: absolute;
            width: 40px; height: 40px;
            background-color: rgba(255, 255, 255, 0.4); /* Slightly more opaque thumb */
            border-radius: 50%;
            transform: translate(0, 0);
            transition: transform 0.05s linear; /* Smooth thumb movement */
            border: 1px solid rgba(255, 255, 255, 0.3);
        }

        #shootButtonTouch {
            width: 80px; height: 80px;
            background-color: rgba(255, 0, 0, 0.4);
            transition: background-color 0.1s ease; /* Smooth color change on press */
        }
        #shootButtonTouch:active { /* Visual feedback on press */
            background-color: rgba(255, 0, 0, 0.7);
        }

        #viewToggleTouchButton {
            width: 60px; height: 60px;
            background-color: rgba(156, 39, 176, 0.5);
            position: absolute;
            right: 20px;
            top: 20px; /* Position at top right */
            z-index: 6; /* Ensure it's above other elements if needed */
            pointer-events: auto; /* Make sure it's clickable */
        }
         #viewToggleTouchButton:active {
             background-color: rgba(156, 39, 176, 0.8);
         }

        #levelInfo {
            position: absolute;
            top: 50%; left: 50%;
            transform: translate(-50%, -50%);
            color: white;
            font-size: clamp(2rem, 5vw, 3rem); /* Responsive font size */
            text-shadow: 3px 3px 6px rgba(0, 0, 0, 0.8); /* Stronger shadow */
            display: none; /* Controlled by JS */
            text-align: center;
            z-index: 5;
            line-height: 1.2;
            background-color: rgba(0,0,0,0.3); /* Slight background for readability */
            padding: 10px 20px;
            border-radius: 10px;
        }

        #damageOverlay {
            position: absolute;
            top: 0; left: 0;
            width: 100%; height: 100%;
            background-color: rgba(255, 0, 0, 0); /* Start transparent */
            pointer-events: none;
            z-index: 4; /* Below UI, above game */
            transition: background-color 0.5s ease-out; /* Control fade out */
        }

        #minimap {
            position: absolute;
            bottom: 20px;
            left: 20px;
            width: 150px; /* Default size */
            height: 150px;
            background-color: rgba(0, 0, 0, 0.6); /* More opaque */
            border: 2px solid rgba(255, 255, 255, 0.4); /* Less bright border */
            border-radius: 50%;
            overflow: hidden;
            z-index: 5;
            display: none; /* Controlled by JS */
            box-shadow: 0 0 10px rgba(0,0,0,0.5); /* Add shadow */
        }
        #minimap canvas { /* Ensure canvas fills the div */
             display: block;
             width: 100%;
             height: 100%;
        }


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

        @keyframes pulse {
            0% { text-shadow: 0 0 10px rgba(255,0,0,0.8), 0 0 20px rgba(255,0,0,0.5), 0 0 30px rgba(255,0,0,0.3); }
            100% { text-shadow: 0 0 15px rgba(255,0,0,0.9), 0 0 25px rgba(255,0,0,0.6), 0 0 35px rgba(255,0,0,0.4), 0 0 45px rgba(255,0,0,0.2); }
        }

        @keyframes sheen {
            0% { transform: translateX(-150%) rotate(45deg); }
            50% { transform: translateX(150%) rotate(45deg); } /* Pass through */
            100% { transform: translateX(150%) rotate(45deg); } /* Stay off screen */
        }

        @keyframes subtlePatternShift {
             0% { background-position: 0 0; }
             100% { background-position: 200px 200px; } /* Adjust distance for speed */
        }