:root {
    --bg-color: #000000;
    --text-color: #e0e0e0;
    --primary-color: #4a90e2;
    --panel-bg: #2c2c2c;
    --border-color: #444;
    --input-bg: #333;
    --danger-color: #e24a4a;

    --status-learning: #f39c12;
    --status-understood: #2ecc71;
    --status-mastered: #3498db;
}

body, html {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
}

#graph-container {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
}

#graph {
    width: 100%;
    height: 100%;
    display: block;
    background-image: url('/BranchedNotes.png');
    background-size: cover;
}

/* Node and Link Styles */
.link {
    stroke: #999;
    stroke-opacity: 0.6;
    stroke-width: 2px;
}

.node circle {
    stroke: #fff;
    stroke-width: 1.5px;
    cursor: pointer;
    transition: transform 0.2s ease-in-out;
}

.node circle.selected {
    stroke: var(--primary-color);
    stroke-width: 4px;
}

.node:hover circle {
    transform: scale(1.1);
}

.node text {
    pointer-events: none;
    font-size: 14px;
    fill: var(--text-color);
    text-anchor: middle;
    transform: translateY(-20px);
}

/* Tooltip */
.tooltip {
    position: absolute;
    visibility: hidden;
    background-color: var(--panel-bg);
    color: var(--text-color);
    padding: 10px;
    border-radius: 6px;
    border: 1px solid var(--border-color);
    max-width: 300px;
    font-size: 14px;
    line-height: 1.4;
    z-index: 100;
    pointer-events: none; /* So it doesn't interfere with mouse events on the graph */
    box-shadow: 0 3px 10px rgba(0,0,0,0.3);
}

.tooltip strong {
    color: var(--primary-color);
    display: block;
    margin-bottom: 5px;
}

/* UI Controls */
#controls {
    position: absolute;
    top: 20px;
    left: 20px;
    background: var(--panel-bg);
    padding: 15px;
    border-radius: 8px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.4);
    border: 1px solid var(--border-color);
    max-width: 300px;
    z-index: 5;
    transition: transform 0.3s ease-in-out, opacity 0.3s ease-in-out;
}

#controls.hidden {
    transform: translateX(-110%);
    opacity: 0;
    pointer-events: none;
}

#hide-controls-btn {
    position: absolute;
    top: 15px;
    right: 15px;
    background: none;
    border: 1px solid var(--border-color);
    width: 24px;
    height: 24px;
    border-radius: 4px;
    color: var(--text-color);
    cursor: pointer;
    font-size: 16px;
    line-height: 1;
    padding: 0;
    display: flex;
    align-items: center;
    justify-content: center;
}

#hide-controls-btn:hover {
    background: var(--input-bg);
    filter: none;
}

#show-controls-btn {
    position: absolute;
    top: 20px;
    left: 20px;
    z-index: 4;
    background: var(--primary-color);
    border: none;
    color: white;
    font-size: 20px;
    padding: 10px;
    border-radius: 0 8px 8px 0;
    cursor: pointer;
    box-shadow: 0 4px 10px rgba(0,0,0,0.3);
    display: none;
}

h1 {
    margin: 0 0 10px 0;
    padding-right: 30px; /* Space for hide button */
    font-size: 24px;
    color: var(--primary-color);
    opacity: 0.9;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

#controls p {
    font-size: 14px;
    margin: 0 0 15px 0;
    opacity: 0.8;
}

#add-node-form p {
    font-size: 13px;
    margin: 0 0 10px 0;
    opacity: 0.7;
    min-height: 1.2em; /* Prevents layout shift */
}

.control-box input {
    width: calc(100% - 12px);
    padding: 8px;
    margin-bottom: 10px;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    border-radius: 4px;
}

button {
    padding: 8px 15px;
    border: none;
    border-radius: 4px;
    background: var(--primary-color);
    color: white;
    cursor: pointer;
    transition: background 0.2s;
}

button:hover {
    filter: brightness(1.1);
}

button:disabled {
    background: #555;
    cursor: not-allowed;
}

button:disabled:hover {
    filter: none;
}

#add-node-btn {
    width: 100%;
}

.control-box {
    border-top: 1px solid var(--border-color);
    padding-top: 15px;
    margin-top: 15px;
}

#workspace-controls {
    display: flex;
    align-items: center;
    gap: 10px;
    border-top: none;
    padding-top: 0;
    margin-top: 0;
    margin-bottom: 15px;
}

#workspace-selector {
    flex-grow: 1;
    padding: 8px;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    border-radius: 4px;
    font-family: inherit;
    font-size: 14px;
}

#manage-workspaces-btn {
    padding: 8px 12px;
    background-color: #555;
    font-size: 13px;
}

/* Sidebar */
.sidebar {
    position: absolute;
    top: 20px;
    right: -400px;
    width: 350px;
    max-height: calc(100vh - 40px);
    background: var(--panel-bg);
    padding: 20px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.5);
    transition: right 0.3s ease-in-out;
    display: flex;
    flex-direction: column;
    gap: 10px;
    border: 1px solid var(--border-color);
    border-radius: 8px;
    overflow-y: auto;
    z-index: 10;
}

.sidebar.show {
    right: 20px;
}

.sidebar h3 {
    margin-top: 0;
    color: var(--primary-color);
}

.sidebar label {
    font-size: 14px;
    opacity: 0.8;
}

.sidebar input, .sidebar textarea, .sidebar select {
    width: 100%;
    padding: 8px;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    border-radius: 4px;
    box-sizing: border-box;
    font-family: inherit;
    font-size: 14px;
}

.sidebar textarea {
    resize: vertical;
    min-height: 4em; /* Set a minimum height */
    overflow-y: hidden; /* Hide scrollbar until needed */
}

#resources-links {
    margin-top: 8px;
    display: flex;
    flex-direction: column;
    gap: 5px;
    max-height: 120px;
    overflow-y: auto;
    background-color: var(--input-bg);
    padding: 8px;
    border-radius: 4px;
    border: 1px solid var(--border-color);
}

#resources-links a {
    color: var(--primary-color);
    text-decoration: none;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    padding: 2px 0;
}

#resources-links a:hover {
    text-decoration: underline;
}

.content-editor-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

#expand-content-btn,
#expand-resources-btn {
    background: none;
    border: 1px solid var(--border-color);
    color: var(--text-color);
    opacity: 0.7;
    width: 28px;
    height: 28px;
    padding: 0;
    font-size: 16px;
    border-radius: 4px;
}

#expand-content-btn:hover,
#expand-resources-btn:hover {
    background-color: var(--input-bg);
    opacity: 1;
}

.close-btn {
    position: absolute;
    top: 10px;
    right: 15px;
    background: none;
    border: none;
    font-size: 24px;
    color: var(--text-color);
}

#delete-node-btn {
    background-color: var(--danger-color);
    margin-top: 10px;
}

#delete-node-btn:hover {
    filter: brightness(1.1);
}

/* Modal Styles */
.modal-overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0, 0, 0, 0.7);
    display: flex;
    align-items: center;
    justify-content: flex-end;
    z-index: 1000;
    display: none; /* Hidden by default */
    opacity: 0.8;
}

.modal-content {
    background: var(--panel-bg);
    padding: 30px;
    border-radius: 8px;
    width: 90%;
    max-width: 600px;
    position: relative;
    border: 1px solid var(--border-color);
    max-height: 80vh;
    overflow-y: auto;
    display: flex;
    flex-direction: column;
}

.modal-content.fullscreen-editor {
    width: 90vw;
    height: 90vh;
    max-width: 1400px;
    padding: 0;
}

.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 25px;
    border-bottom: 1px solid var(--border-color);
    position: relative;
}

.modal-header h3 {
    margin: 0;
    color: var(--primary-color);
}

.modal-header .close-btn {
    position: static; /* Override absolute positioning */
    font-size: 30px;
    line-height: 1;
}

.modal-footer {
    padding: 15px 25px;
    border-top: 1px solid var(--border-color);
    display: flex;
    justify-content: flex-end;
}

#fullscreen-content-textarea {
    flex-grow: 1;
    width: 100%;
    height: 100%;
    background-color: var(--bg-color);
    color: var(--text-color);
    border: none;
    padding: 25px;
    box-sizing: border-box;
    font-size: 16px;
    line-height: 1.6;
    resize: none;
    font-family: inherit;
}

#fullscreen-content-textarea:focus {
    outline: none;
}

.modal-content .close-btn {
    top: 15px;
}

#workspace-modal .modal-content {
    max-width: 500px;
}

#workspace-list {
    margin-bottom: 20px;
    max-height: 250px;
    overflow-y: auto;
}

.workspace-item {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 10px;
    background-color: var(--input-bg);
    border-radius: 4px;
    margin-bottom: 8px;
}

.workspace-item span {
    font-weight: 500;
}

.workspace-item .delete-ws-btn {
    background-color: var(--danger-color);
    padding: 4px 8px;
    font-size: 12px;
}

#add-workspace-form {
    display: flex;
    gap: 10px;
    margin-top: 20px;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
}

#add-workspace-form input {
    flex-grow: 1;
    margin-bottom: 0;
}

#add-workspace-form button {
    white-space: nowrap;
}

#quiz-container .question-block {
    margin-bottom: 20px;
    padding-bottom: 15px;
    border-bottom: 1px solid var(--border-color);
}

#quiz-container .question-block:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

#quiz-container .question-text {
    font-weight: bold;
    margin-bottom: 10px;
}

#quiz-container .options-list {
    display: flex;
    flex-direction: column;
    gap: 8px;
    padding: 0;
}

#quiz-container .option-item {
    cursor: pointer;
    display: flex;
    align-items: center;
    padding: 8px;
    border-radius: 4px;
    transition: background-color 0.2s;
}

#quiz-container .option-item:hover {
    background-color: var(--input-bg);
}

#quiz-container input[type="radio"] {
    margin-right: 10px;
    accent-color: var(--primary-color);
}

#quiz-container .feedback {
    display: none;
    margin-top: 10px;
    font-size: 14px;
    padding: 8px 12px;
    border-radius: 4px;
    font-weight: 500;
}

#quiz-container .feedback.correct {
    display: block;
    background-color: rgba(46, 204, 113, 0.1);
    border: 1px solid var(--status-understood);
    color: var(--status-understood);
}

#quiz-container .feedback.incorrect {
    display: block;
    background-color: rgba(226, 74, 74, 0.1);
    border: 1px solid var(--danger-color);
    color: var(--danger-color);
}

#check-answers-btn {
    margin-top: 20px;
}

/* Flashcard Styles */
#flashcard-container {
    flex-grow: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    perspective: 1000px;
    min-height: 250px;
}

.flashcard {
    width: 100%;
    height: 100%;
    min-height: 250px;
    position: relative;
    transform-style: preserve-3d;
    transition: transform 0.6s;
    cursor: pointer;
}

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

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
}

.flashcard-front,
.flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 20px;
    background: var(--input-bg);
    border: 1px solid var(--border-color);
    border-radius: 8px;
    font-size: 1.2rem;
    box-sizing: border-box;
}

.flashcard-back {
    transform: rotateY(180deg);
    font-size: 1rem;
}

#flashcard-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 20px;
    padding-top: 15px;
    border-top: 1px solid var(--border-color);
}

#flashcard-counter {
    font-size: 14px;
    color: var(--text-color);
    opacity: 0.8;
}