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

body {
    line-height: 1.6;
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
}

/* Card styles */
.card {
    border-radius: 8px;
    margin-bottom: 20px;
    overflow: hidden;
}

.card-body {
    padding: 20px;
}

/* Form styles */
form {
    margin-bottom: 20px;
}

.form-group {
    margin-bottom: 15px;
}

label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
}

/* Checkbox and radio styles */
.checkbox-group {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
    gap: 10px;
}

.checkbox-label {
    display: flex;
    align-items: center;
    margin-bottom: 0;
    cursor: pointer;
    padding: 5px;
    border-radius: 4px;
    transition: background-color 0.2s;
}

.checkbox-label input {
    margin-right: 8px;
}

/* Flashcard styles */
.flashcard {
    border-radius: 8px;
    max-width: 650px;
    margin: 30px auto;
    height: 380px;
    perspective: 1000px;
    position: relative;
    cursor: pointer;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.8s;
    transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg);
}

.flashcard-front, .flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
    padding: 30px;
    border-radius: 8px;
}

.flashcard-front {
    font-size: 2.5rem;
    font-weight: 500;
}

.flashcard-back {
    transform: rotateY(180deg);
    font-size: 1.25rem;
    text-align: left;
    overflow-y: auto;
}

.flashcard-meta {
    position: absolute;
    bottom: 20px;
    left: 20px;
    font-size: 0.9rem;
}

.flashcard-definition {
    margin-bottom: 15px;
}

.flashcard-detail {
    display: flex;
    margin-bottom: 5px;
    font-size: 0.95rem;
}

.flashcard-detail strong {
    min-width: 100px;
    margin-right: 10px;
}

.flashcard-notes {
    margin-top: 15px;
    padding-top: 15px;
    border-top: 1px solid #eee;
}

.flashcard-back .btn-group {
    margin-top: 20px;
}

.hidden {
    display: none;
}

/* Progress indicator */
.progress-indicator {
    display: flex;
    justify-content: center;
    margin-bottom: 30px;
}

.progress-dot {
    width: 12px;
    height: 12px;
    border-radius: 50%;
    margin: 0 5px;
    transition: background-color 0.3s;
}

/* Utility classes */
.text-center {
    text-align: center;
}

.mb-20 {
    margin-bottom: 20px;
}

/* Button styles */
.btn {
    display: inline-block;
    background-color: #3498db;
    color: #fff;
    border: none;
    padding: 10px 20px;
    cursor: pointer;
    border-radius: 4px;
    text-decoration: none;
    transition: background-color 0.3s;
}

.btn:hover {
    background-color: #2980b9;
}

.btn-danger {
    background-color: #e74c3c;
}

.btn-danger:hover {
    background-color: #c0392b;
}

.btn-success {
    background-color: #2ecc71;
}

.btn-success:hover {
    background-color: #27ae60;
}

/* Card styles */
.card-header {
    background-color: #3498db;
    color: #fff;
    padding: 15px 20px;
}

/* Progress indicator */
.progress-dot.active {
    background-color: #0d6efd;
}

.progress-dot.correct {
    background-color: #28a745;
}

.progress-dot.incorrect {
    background-color: #dc3545;
}

/* Stats styles */
.difficulty-indicator {
    display: inline-block;
    width: 12px;
    height: 12px;
    border-radius: 50%;
    margin-right: 5px;
}

.difficulty-low {
    background-color: #28a745;
}

.difficulty-medium {
    background-color: #ffc107;
}

.difficulty-high {
    background-color: #dc3545;
}

.error {
    color: #e74c3c;
    background-color: #fadbd8;
    padding: 10px;
    border-radius: 4px;
    margin-bottom: 20px;
}

.success {
    color: #27ae60;
    background-color: #d5f5e3;
    padding: 10px;
    border-radius: 4px;
    margin-bottom: 20px;
}