/* General Styles & Themes */
:root {
    --font-retro: 'Courier New', Courier, monospace;
    --radius-m: 8px;
    --shadow-m: 0 4px 12px rgba(0, 0, 0, 0.2);
    --shadow-l: 0 8px 24px rgba(0, 0, 0, 0.3);
    --transition-speed: 0.3s;
}

body {
    font-family: var(--font-retro);
    display: flex;
    justify-content: center;
    align-items: center;
    height: 100vh;
    margin: 0;
    transition: background-color var(--transition-speed), color var(--transition-speed);
}

/* --- Theme Definitions --- */
body.dark-theme {
    --bg-color: #1a1a1a;
    --surface-color: #2a2a2a;
    --text-color: #f0f0f0;
    --primary-color: #00ff00;
    --accent-color: #ff00ff;
    --border-color: #444;
    --canvas-bg: #000;
}

body.light-theme {
    --bg-color: #f0f0f0;
    --surface-color: #ffffff;
    --text-color: #1a1a1a;
    --primary-color: #008000;
    --accent-color: #d900d9;
    --border-color: #ccc;
    --canvas-bg: #e0e0e0;
}
/* --- End Theme Definitions --- */

body {
    background-color: var(--bg-color);
    color: var(--text-color);
}

/* Game Container & Canvas */
.game-container {
    position: relative;
    display: flex;
    justify-content: center;
    align-items: center;
    background-color: var(--surface-color);
    border-radius: var(--radius-m);
    box-shadow: var(--shadow-l);
    padding: 24px; /* Increased padding for a larger canvas */
}

canvas {
    background-color: var(--canvas-bg);
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

/* HUD (Heads-Up Display) */
#hud {
    position: absolute;
    top: 24px;
    left: 24px;
    right: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    z-index: 10;
}

#score-container {
    font-size: 1.8em;
    font-weight: bold;
    color: var(--text-color);
    background: rgba(0,0,0,0.3);
    padding: 8px 16px;
    border-radius: var(--radius-m);
}

body.light-theme #score-container {
    background: rgba(255,255,255,0.5);
}


#settings-btn {
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color var(--transition-speed);
}

#settings-btn svg {
    fill: var(--text-color);
    transition: transform 0.5s;
}

#settings-btn:hover {
    background-color: rgba(128, 128, 128, 0.2);
}
#settings-btn:hover svg {
    transform: rotate(90deg);
}


/* Start Screen */
#start-screen {
    position: absolute;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.8);
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    z-index: 20;
    border-radius: 4px;
}

body.light-theme #start-screen {
    background-color: rgba(255, 255, 255, 0.8);
}

#start-screen h1 {
    font-size: 5em;
    color: var(--primary-color);
    text-shadow: 0 0 10px var(--primary-color);
    margin-bottom: 32px;
}

/* Buttons */
#play-btn, .difficulty-btn, #close-settings-btn {
    font-family: var(--font-retro);
    font-size: 1.2em;
    padding: 12px 24px;
    border: 2px solid var(--primary-color);
    background-color: transparent;
    color: var(--primary-color);
    cursor: pointer;
    border-radius: var(--radius-m);
    transition: background-color var(--transition-speed), color var(--transition-speed), box-shadow var(--transition-speed);
    text-transform: uppercase;
}

#play-btn:hover, .difficulty-btn:hover, #close-settings-btn:hover {
    background-color: var(--primary-color);
    color: var(--surface-color);
    box-shadow: 0 0 15px var(--primary-color);
}

.difficulty-btn.active {
    background-color: var(--primary-color);
    color: var(--surface-color);
    box-shadow: 0 0 15px var(--primary-color);
}

/* Settings Modal */
#settings-backdrop {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: rgba(0, 0, 0, 0.6);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
    opacity: 1;
    transition: opacity var(--transition-speed);
}

#settings-backdrop.hidden {
    opacity: 0;
    pointer-events: none;
}

#settings-panel {
    background-color: var(--surface-color);
    padding: 24px 32px;
    border-radius: var(--radius-m);
    box-shadow: var(--shadow-l);
    width: 90%;
    max-width: 400px;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 24px;
}

#settings-panel h2 {
    margin: 0;
    text-align: center;
    font-size: 2em;
    color: var(--primary-color);
}

.settings-group {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 16px;
}

.settings-group label {
    font-size: 1.2em;
    font-weight: bold;
}

#difficulty-btns {
    display: flex;
    gap: 8px;
}

.difficulty-btn {
    font-size: 0.9em;
    padding: 8px 12px;
}

#close-settings-btn {
    margin-top: 16px;
    border-color: var(--accent-color);
    color: var(--accent-color);
}
#close-settings-btn:hover {
    background-color: var(--accent-color);
    color: var(--surface-color);
    box-shadow: 0 0 15px var(--accent-color);
}


/* Theme Switch */
.theme-switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.theme-switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #444;
    transition: var(--transition-speed);
    border-radius: 34px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: var(--transition-speed);
    border-radius: 50%;
}

input:checked + .slider {
    background-color: var(--primary-color);
}

body.light-theme input:checked + .slider {
    background-color: #ccc;
}

body.light-theme .slider {
    background-color: #ccc;
}

body.light-theme input:checked + .slider {
    background-color: var(--primary-color);
}


input:checked + .slider:before {
    transform: translateX(26px);
}

.hidden {
    display: none;
}