:root {
    --primary-bg: #f4f7f9;
    --secondary-bg: #ffffff;
    --primary-text: #2c3e50;
    --accent-color: #3498db;
    --accent-hover: #2980b9;
    --correct-bg: #e8f5e9;
    --correct-border: #a5d6a7;
    --correct-text: #2e7d32;
    --incorrect-bg: #ffebee;
    --incorrect-border: #ef9a9a;
    --incorrect-text: #c62828;
    --neutral-bg: #e1f5fe;
    --neutral-border: #81d4fa;
    --light-gray: #e0e0e0;
    --dark-gray: #757575;
    --shadow: 0 4px 12px rgba(0, 0, 0, 0.08);
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
    background-color: var(--primary-bg);
    color: var(--primary-text);
    line-height: 1.6;
}

#app-container {
    max-width: 900px;
    margin: 2rem auto;
    background-color: var(--secondary-bg);
    border-radius: 12px;
    box-shadow: var(--shadow);
    overflow: hidden;
}

.main-header {
    background: linear-gradient(135deg, var(--accent-color), var(--accent-hover));
    color: white;
    padding: 1rem 1.5rem;
}

.header-content {
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 1rem;
}

.header-content h1 {
    font-size: 1.5rem;
    font-weight: 600;
}

.controls {
    display: flex;
    align-items: center;
    gap: 15px;
    flex-wrap: wrap;
}

.control-btn, .nav-btn, .start-button {
    padding: 0.6rem 1.2rem;
    border: none;
    border-radius: 6px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    transition: all 0.2s ease-in-out;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.control-btn {
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
}

.control-btn:hover {
    background-color: rgba(255, 255, 255, 0.3);
    transform: translateY(-2px);
}

.toggle-container {
    display: flex;
    align-items: center;
    gap: 8px;
    background-color: rgba(0, 0, 0, 0.1);
    padding: 0.4rem 0.8rem;
    border-radius: 20px;
}

.toggle-label {
    font-size: 0.9rem;
}

.switch {
    position: relative;
    display: inline-block;
    width: 44px;
    height: 24px;
}

.switch input { display: none; }

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: .4s;
    border-radius: 24px;
}

.slider:before {
    position: absolute;
    content: "";
    height: 18px;
    width: 18px;
    left: 3px;
    bottom: 3px;
    background-color: white;
    transition: .4s;
    border-radius: 50%;
}

input:checked + .slider { background-color: #66bb6a; }
input:checked + .slider:before { transform: translateX(20px); }

main {
    padding: 2rem;
}

.hidden { display: none !important; }

#welcome-screen { text-align: center; }
#welcome-screen h2 { margin-bottom: 1rem; color: var(--accent-color); font-weight: 600; }
#welcome-screen p { margin-bottom: 1.5rem; max-width: 600px; margin-left: auto; margin-right: auto; color: var(--dark-gray); }

.start-button {
    background-color: var(--accent-color);
    color: white;
    padding: 0.8rem 2.5rem;
    font-size: 1.1rem;
    font-weight: 600;
}
.start-button:hover { background-color: var(--accent-hover); transform: translateY(-2px); box-shadow: 0 4px 8px rgba(0,0,0,0.1);}

#progress-bar-container {
    width: 100%;
    background-color: var(--light-gray);
    border-radius: 5px;
    margin-bottom: 1rem;
    height: 8px;
}

#progress-bar {
    height: 100%;
    width: 0;
    background: linear-gradient(90deg, #3498db, #8e44ad);
    border-radius: 5px;
    transition: width 0.3s ease-in-out;
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
}

.question-counter {
    font-size: 0.9rem;
    color: var(--dark-gray);
}

.question-domain {
    background-color: var(--primary-bg);
    color: var(--dark-gray);
    padding: 3px 12px;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
    border: 1px solid var(--light-gray);
}

#question-text {
    font-size: 1.25rem;
    margin-bottom: 1.5rem;
    font-weight: 500;
}

#options-container .option {
    display: flex;
    width: 100%;
    text-align: left;
    background-color: var(--secondary-bg);
    border: 1px solid var(--light-gray);
    padding: 1rem;
    margin-bottom: 0.75rem;
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.2s ease;
    font-size: 1rem;
}
#options-container .option:hover { border-color: var(--accent-color); background-color: #f1f8ff; }
#options-container .option.selected { border-color: var(--accent-color); background-color: var(--neutral-bg); font-weight: 500; }
#options-container.answered .option { cursor: not-allowed; }
#options-container.answered .option.correct { background-color: var(--correct-bg); border-color: var(--correct-border); color: var(--correct-text); font-weight: bold; }
#options-container.answered .option.incorrect { background-color: var(--incorrect-bg); border-color: var(--incorrect-border); color: var(--incorrect-text); }
#options-container.answered .option.correct-choice { background-color: var(--neutral-bg); border-color: var(--neutral-border); font-weight: bold; }
#options-container.answered .option:not(.selected):not(.correct):not(.correct-choice) { opacity: 0.7; }

#navigation-controls {
    display: flex;
    justify-content: flex-end;
    margin-top: 1.5rem;
}

.nav-btn { background-color: var(--accent-color); color: white; }
.nav-btn:hover { background-color: var(--accent-hover); }
.nav-btn.hidden { display: none; }
.nav-btn:disabled { background-color: var(--light-gray); cursor: not-allowed; }

#feedback-container {
    margin-top: 1.5rem;
    padding: 1rem;
    border-radius: 8px;
}
#feedback-container.correct { background-color: var(--correct-bg); }
#feedback-container.incorrect { background-color: var(--incorrect-bg); }
#feedback-text { font-weight: bold; font-size: 1.1rem; margin-bottom: 0.5rem; }
#feedback-text.correct { color: var(--correct-text); }
#feedback-text.incorrect { color: var(--incorrect-text); }
#explanation-text { color: var(--dark-gray); }

#results-screen h2, #results-screen h3 { color: var(--accent-color); margin-bottom: 1rem; padding-bottom: 0.5rem; font-weight: 600; }
#results-screen h3 { border-bottom: 2px solid var(--primary-bg); }

#score-summary { text-align: center; background-color: var(--primary-bg); padding: 1.5rem; border-radius: 8px; margin-bottom: 2rem; }
#score-summary p { font-size: 1.5rem; margin: 0; }
#score-summary #pass-fail-status { font-size: 2.2rem; margin-top: 0.5rem; display: block; font-weight: 700; }
#pass-fail-status.pass { color: #2e7d32; }
#pass-fail-status.fail { color: #c62828; }

#domain-breakdown { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1rem; margin-bottom: 2rem; }
.domain-card { border: 1px solid var(--light-gray); padding: 1rem; border-radius: 8px; background-color: #fafafa; }
.domain-card h4 { margin-bottom: 0.5rem; font-weight: 600; }
.domain-card p { margin: 0.25rem 0; }
.domain-card strong { color: var(--accent-color); }

#study-recommendations ul { list-style-type: none; padding-left: 0; }
#study-recommendations li { background-color: #fffbe6; border-left: 4px solid #fdd835; padding: 1rem; margin-bottom: 0.75rem; border-radius: 0 4px 4px 0;}

.results-controls { text-align: center; margin-top: 2rem; display: flex; gap: 1rem; justify-content: center; }
.results-controls .control-btn { background-color: var(--accent-color); }
.results-controls .control-btn:hover { background-color: var(--accent-hover); }

#review-screen h2 { color: var(--accent-color); margin-bottom: 1.5rem; text-align: center; }
.review-item { margin-bottom: 2rem; padding: 1.5rem; border: 1px solid var(--light-gray); border-radius: 8px; page-break-inside: avoid; }
.review-item .review-question-header { font-weight: bold; font-size: 1.1rem; margin-bottom: 1rem; }
.review-item .review-option { padding: 8px; margin: 5px 0; border-radius: 4px; border-left: 4px solid transparent; }
.review-item .review-option.user-incorrect { background-color: var(--incorrect-bg); border-left-color: #c62828; }
.review-item .review-option.correct-answer { background-color: var(--correct-bg); border-left-color: #2e7d32; font-weight: bold; }
.review-item .review-explanation { margin-top: 1rem; padding: 1rem; background-color: var(--primary-bg); border-radius: 5px; }
.review-explanation p:first-child { font-weight: bold; }
.review-navigation { text-align: center; margin-top: 2rem; }

@media print {
    body { font-size: 10pt; color: #000; }
    #app-container { box-shadow: none; margin: 0; max-width: 100%; border-radius: 0; }
    .main-header, .results-controls, .review-navigation, #welcome-screen, #test-screen { display: none; }
    main { padding: 1rem; }
    #results-screen, #review-screen { display: block !important; }
    #domain-breakdown { grid-template-columns: 1fr; }
    .domain-card, .review-item { border: 1px solid #ccc; }
    #score-summary { background-color: #eee; }
    #study-recommendations li { background-color: #eee; border-left: 2px solid #aaa; }
    h1, h2, h3, h4 { color: #000; }
    .pass { color: green !important; }
    .fail { color: red !important; }
}

@media (max-width: 768px) {
    body { font-size: 14px; }
    #app-container { margin: 0.5rem; }
    .header-content { flex-direction: column; align-items: flex-start; }
    .header-content h1 { font-size: 1.3rem; }
    main { padding: 1rem; }
    #question-text { font-size: 1.1rem; }
}