.tool-main {
    max-width: 800px;
    margin: 0 auto;
    padding: 20px;
}

.control-panel {
    display: flex;
    gap: 15px;
    margin-bottom: 30px;
    align-items: center;
    flex-wrap: wrap;
}

.stats-info {
    margin-left: auto;
    font-size: 0.9em;
    color: var(--text-secondary);
}

.study-area {
    margin-bottom: 40px;
    perspective: 1000px;
}

.flashcard-container {
    position: relative;
    width: 100%;
    height: 400px;
    cursor: pointer;
}

.flashcard {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.6s;
    transform-style: preserve-3d;
    box-shadow: 0 4px 8px rgba(0,0,0,0.1);
    border-radius: 12px;
}

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

.card-front, .card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 30px;
    border-radius: 12px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
}

.card-front {
    background: linear-gradient(135deg, var(--bg-secondary), var(--bg-primary));
}

.card-back {
    transform: rotateY(180deg);
    background: var(--bg-primary);
    border-color: var(--primary-color);
}

.card-content {
    font-size: 1.5em;
    line-height: 1.6;
    color: var(--text-primary);
    white-space: pre-wrap;
    overflow-y: auto;
    max-height: 100%;
    width: 100%;
}

.card-hint {
    position: absolute;
    bottom: 20px;
    font-size: 0.8em;
    color: var(--text-secondary);
    opacity: 0.6;
}

.card-actions {
    margin-top: 30px;
    display: flex;
    gap: 20px;
}

.action-btn {
    padding: 10px 20px;
    border: none;
    border-radius: 20px;
    cursor: pointer;
    font-weight: bold;
    transition: transform 0.1s;
}

.action-btn:active {
    transform: scale(0.95);
}

.action-btn.forgot {
    background-color: #ff4d4f;
    color: white;
}

.action-btn.remembered {
    background-color: #52c41a;
    color: white;
}

.navigation-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 20px;
    margin-top: 20px;
}

.nav-btn {
    background: transparent;
    border: 1px solid var(--border-color);
    padding: 8px 16px;
    border-radius: 4px;
    color: var(--text-primary);
    cursor: pointer;
}

.nav-btn:hover {
    background: var(--bg-secondary);
}

.empty-state {
    text-align: center;
    padding: 50px;
    background: var(--bg-secondary);
    border-radius: 8px;
    border: 2px dashed var(--border-color);
}

.empty-icon {
    font-size: 4em;
    margin-bottom: 20px;
}

.modal {
    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;
}

.modal-content {
    background: var(--bg-primary);
    padding: 30px;
    border-radius: 8px;
    width: 90%;
    max-width: 600px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.2);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: bold;
}

.form-group textarea {
    width: 100%;
    padding: 10px;
    border: 1px solid var(--border-color);
    border-radius: 4px;
    background: var(--bg-secondary);
    color: var(--text-primary);
    resize: vertical;
}

.modal-actions {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
}

.card-list-section {
    margin-top: 50px;
    border-top: 1px solid var(--border-color);
    padding-top: 30px;
}

.card-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(250px, 1fr));
    gap: 15px;
    margin-top: 20px;
}

.list-item {
    background: var(--bg-secondary);
    padding: 15px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.list-item-content {
    font-size: 0.9em;
    color: var(--text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.list-item-actions {
    display: flex;
    justify-content: flex-end;
    gap: 10px;
    margin-top: auto;
}

.icon-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 1.1em;
    opacity: 0.7;
    transition: opacity 0.2s;
}

.icon-btn:hover {
    opacity: 1;
}

.delete-btn { color: #ff4d4f; }
.edit-btn { color: var(--primary-color); }