* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: Arial, sans-serif;
    overflow: hidden;
    background: #000;
}

.app-container {
    position: relative;
    width: 100vw;
    height: 100vh;
}

#starfield {
    display: block;
    background: #000;
    cursor: grab;
}

#starfield:active {
    cursor: grabbing;
}

.controls-panel {
    position: absolute;
    top: 20px;
    right: 20px;
    background: rgba(20, 20, 30, 0.95);
    padding: 20px;
    border-radius: 10px;
    color: #fff;
    min-width: 250px;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.5);
}

.controls-panel h2 {
    margin-bottom: 15px;
    font-size: 20px;
    border-bottom: 2px solid #4a90d9;
    padding-bottom: 10px;
}

.stats {
    margin-bottom: 20px;
}

.stats p {
    margin: 8px 0;
    font-size: 14px;
}

.stats span {
    font-weight: bold;
    color: #4a90d9;
}

.controls {
    margin-bottom: 20px;
}

.toggle {
    display: flex;
    align-items: center;
    cursor: pointer;
    user-select: none;
}

.toggle input[type="checkbox"] {
    margin-right: 10px;
    cursor: pointer;
    width: 18px;
    height: 18px;
}

.done-button {
    width: 100%;
    padding: 12px;
    background: #4a90d9;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    font-weight: bold;
    cursor: pointer;
    transition: background 0.3s;
}

.done-button:hover {
    background: #357abd;
}

.popup {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    background: rgba(0, 0, 0, 0.8);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}

.popup.hidden {
    display: none;
}

.popup-content {
    background: rgba(20, 20, 30, 0.98);
    padding: 30px;
    border-radius: 15px;
    color: #fff;
    max-width: 400px;
    width: 90%;
    box-shadow: 0 8px 30px rgba(0, 0, 0, 0.7);
}

.popup-content h3 {
    margin-bottom: 20px;
    font-size: 22px;
}

#quiz-options {
    margin-bottom: 20px;
}

#quiz-options label {
    display: flex;
    align-items: center;
    margin: 12px 0;
    padding: 10px;
    background: rgba(74, 144, 217, 0.1);
    border-radius: 5px;
    cursor: pointer;
    transition: background 0.2s;
}

#quiz-options label:hover {
    background: rgba(74, 144, 217, 0.2);
}

#quiz-options input[type="radio"] {
    margin-right: 12px;
    cursor: pointer;
    width: 18px;
    height: 18px;
}

#quiz-form button {
    margin-right: 10px;
    padding: 10px 20px;
    font-size: 14px;
    border: none;
    border-radius: 5px;
    cursor: pointer;
}

#quiz-form button[type="submit"] {
    background: #4a90d9;
    color: white;
}

#quiz-form button[type="submit"]:hover {
    background: #357abd;
}

#skip-btn {
    background: #666;
    color: white;
}

#skip-btn:hover {
    background: #555;
}

#feedback-icon {
    font-size: 60px;
    text-align: center;
    margin-bottom: 15px;
}

#feedback-text {
    text-align: center;
    font-size: 20px;
    margin-bottom: 20px;
}

#close-feedback {
    display: block;
    width: 100%;
    padding: 12px;
    background: #4a90d9;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    cursor: pointer;
}

#close-feedback:hover {
    background: #357abd;
}

.results {
    margin-bottom: 20px;
}

.results p {
    margin: 10px 0;
    font-size: 16px;
}

.results span {
    font-weight: bold;
    color: #4a90d9;
}

#reset-btn {
    width: 100%;
    padding: 12px;
    background: #4a90d9;
    color: white;
    border: none;
    border-radius: 5px;
    font-size: 16px;
    cursor: pointer;
}

#reset-btn:hover {
    background: #357abd;
}

.correct {
    color: #4caf50;
}

.incorrect {
    color: #f44336;
}