:root {
    --bg-color: #f4f4f9;
    --text-color: #2c3e50;
    --primary-color: #1a5a96; /* Darkened for contrast 4.5:1 */
    --success-color: #1b7a43; /* Darkened for contrast */
    --fail-color: #c0392b;    /* Darkened for contrast */
    --white: #ffffff;
    --border-color: #ddd;
}
body {
    font-family: system-ui, -apple-system, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    font-size: 20px;
    margin: 0;
    display: flex;
    justify-content: center;
    padding: 10px; /* Reduced for mobile */
    line-height: 1.5;
    box-sizing: border-box;
}
#app-container {
    max-width: 800px;
    width: 100%;
    background: var(--white);
    padding: 1.5rem; /* Reduced for mobile */
    border-radius: 16px;
    box-shadow: 0 4px 20px rgba(0,0,0,0.1);
    box-sizing: border-box;
}
.screen { display: flex; flex-direction: column; gap: 1.5rem; }
.hidden { display: none !important; }
h1 { font-size: 2rem; text-align: center; margin-bottom: 1rem; }
h2 { font-size: 1.5rem; margin-bottom: 1.5rem; }

#progress-bar {
    font-weight: bold;
    text-align: right;
    font-size: 1.2rem;
    color: #666;
}

button {
    font-size: 1.2rem;
    padding: 12px 24px;
    min-height: 56px;
    cursor: pointer;
    border-radius: 12px;
    border: 2px solid var(--border-color);
    background: var(--white);
    transition: all 0.2s;
}
button:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}
button:hover:not(:disabled) { background: #f0f0f0; }

#btn-next, #btn-submit {
    background: var(--primary-color);
    color: white;
    border: none;
    font-weight: bold;
}
#btn-next:hover:not(:disabled), #btn-submit:hover:not(:disabled) { background: #144575; }

#nav-controls {
    display: flex;
    justify-content: space-between;
    margin-top: 2rem;
    gap: 1rem;
}

.option-btn {
    display: block;
    width: 100%;
    text-align: left;
    margin-bottom: 12px;
    padding: 20px;
    border: 2px solid var(--border-color);
    font-size: 1.2rem;
    transition: all 0.2s;
    box-sizing: border-box;
}
.option-btn.selected {
    border-color: var(--primary-color);
    background-color: #eef6fc;
    font-weight: bold;
    box-shadow: 0 0 0 2px var(--primary-color);
}

#result-status {
    font-size: 3rem;
    text-align: center;
    margin: 0;
}
#result-status.pass { color: var(--success-color); }
#result-status.fail { color: var(--fail-color); }
#result-score {
    text-align: center;
    font-size: 1.4rem;
    margin-bottom: 2rem;
}

.review-item {
    padding: 1.5rem;
    border-bottom: 2px solid #eee;
    margin-bottom: 1rem;
}
.review-item p { margin: 0.5rem 0; }
#review-container h3 {
    font-size: 1.8rem;
    border-bottom: 3px solid var(--text-color);
    padding-bottom: 0.5rem;
}
#btn-home {
    margin-top: 2rem;
    width: 100%;
    background: #eee;
}

@media (max-width: 480px) {
    #app-container { padding: 1rem; }
    #nav-controls { flex-direction: column; }
    button { width: 100%; }
    h1 { font-size: 1.6rem; }
}