:root {
    --primary: #28a745; 
    --primary-hover: #218838;
    --accent: #ff9800;
    --danger: #dc3545;
    --bg: #f4f4f9;
}

body {
    font-family: sans-serif;
    background: var(--bg);
    margin: 0;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    flex: 1;
    max-width: 500px;
    margin: 0 auto;
    padding: 20px;
    width: 100%;
    box-sizing: border-box;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

#quiz-screen {
    display: flex;
    flex-direction: column;
    width: 100%;
    align-items: center;
}

h1 { text-align: center; margin-bottom: 20px; color: #333; }

.section-title {
    font-weight: bold;
    margin: 20px 0 10px;
    text-align: center;
    color: #555;
    text-transform: uppercase;
}

.button-group, .quiz-controls {
    display: flex;
    flex-direction: column !important;
    gap: 15px;
    width: 100%;
}

button {
    display: block !important;
    width: 100%;
    padding: 16px;
    border: 2px solid #ddd;
    background: white;
    border-radius: 8px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    text-align: center;
}

button:hover { background: #f0f0f0; }

button.active {
    background: #e9f7ef;
    border-color: var(--primary);
    color: var(--primary);
}

.special-btn.active {
    background: #fff3e0;
    border-color: var(--accent);
    color: #e65100;
}

.action-btn { color: white; border: none; margin-top: 0; transition: background 0.2s; }
.primary { background: var(--primary); }
.primary:hover { background: var(--primary-hover); }

.secondary { background: #6c757d; }
.danger { background: var(--danger); }
button:disabled { opacity: 0.5; cursor: not-allowed; }

.card {
    background: white;
    padding: 25px;
    border-radius: 12px;
    box-shadow: 0 4px 10px rgba(0,0,0,0.1);
    text-align: center;
    margin-bottom: 25px;
    width: 100%;
    box-sizing: border-box;
}

.label { font-size: 0.9rem; color: #888; text-transform: uppercase; }
.question { font-size: 2rem; font-weight: bold; margin: 15px 0; color: #222; }
.hint { color: #888; font-style: italic; margin-bottom: 15px; }

input {
    width: 100%;
    padding: 14px;
    margin-bottom: 10px;
    border: 2px solid #ddd;
    border-radius: 8px;
    font-size: 1.2rem;
    text-align: center;
    box-sizing: border-box;
}
input:focus { border-color: var(--primary); outline: none; }

.feedback { font-weight: bold; margin-top: 10px; font-size: 1.1rem; min-height: 25px;}
.correct { color: var(--primary); }
.wrong { color: var(--danger); }
.typo { color: var(--accent); }

.overlay {
    display: none;
    position: fixed;
    top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.5);
    z-index: 1000;
    justify-content: center;
    align-items: center;
    padding: 20px;
}
.overlay-content {
    background: white;
    padding: 20px;
    border-radius: 12px;
    width: 100%;
    max-width: 400px;
    max-height: 80vh;
    display: flex;
    flex-direction: column;
}
.page-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(60px, 1fr));
    gap: 10px;
    overflow-y: auto;
    margin: 15px 0;
    flex: 1;
}
.page-item label {
    display: block;
    padding: 12px;
    background: #f8f9fa;
    border-radius: 6px;
    font-weight: bold;
    color: #555;
    text-align: center;
    cursor: pointer;
    border: 2px solid transparent;
}
.page-item input { display: none; }
.page-item input:checked + label {
    background: #e9f7ef;
    border-color: var(--primary);
    color: var(--primary);
}

.progress-container {
    background: white;
    padding: 10px;
    border-top: 1px solid #eee;
    text-align: center;
    position: fixed;
    bottom: 0; left: 0; right: 0;
}
.progress-bar-bg { height: 8px; background: #eee; width: 100%; border-radius: 4px; overflow: hidden; margin-top: 5px; }
.progress-bar-fill { height: 100%; background: var(--primary); width: 0%; transition: width 0.3s; }