:root {
    /* Light Mode */
    --bg-color: #f1f3f4;
    --surface-color: #ffffff;
    --text-primary: #202124;
    --text-secondary: #5f6368;
    --border-color: #e0e0e0;
    --accent-color: #1a73e8;
    --danger-color: #d93025;
    --card-text: #202124;
    --hover-overlay: rgba(0,0,0,0.05);
    --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

[data-theme="dark"] {
    /* Dark Mode */
    --bg-color: #121212;
    --surface-color: #1e1e1e;
    --text-primary: #e8eaed;
    --text-secondary: #9aa0a6;
    --border-color: #3c4043;
    --accent-color: #8ab4f8;
    --card-text: #202124; /* Keep text dark on pastel notes */
    --hover-overlay: rgba(255,255,255,0.05);
}

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

body {
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-primary);
    display: flex;
    flex-direction: column;
    height: 100vh;
    overflow: hidden;
    transition: background-color 0.3s, color 0.3s;
}

/* Header */
.app-header { display: flex; justify-content: space-between; align-items: center; padding: 12px 24px; background-color: var(--surface-color); border-bottom: 1px solid var(--border-color); z-index: 10; }
.header-left { display: flex; align-items: center; gap: 16px; }
.header-left button { background: none; border: none; font-size: 24px; cursor: pointer; color: var(--text-primary); }
.header-left h1 { font-size: 1.2rem; color: var(--text-secondary); }
.header-center { flex: 1; max-width: 600px; margin: 0 20px; }
#searchInput { width: 100%; padding: 12px; border: 1px solid var(--border-color); border-radius: 8px; font-size: 16px; background-color: var(--bg-color); color: var(--text-primary); }
.header-right button { background: none; border: none; font-size: 20px; margin-left: 10px; cursor: pointer; }

/* Layout */
.app-container { display: flex; flex: 1; overflow: hidden; }
.sidebar { width: 250px; background-color: var(--surface-color); border-right: 1px solid var(--border-color); padding: 16px 0; transition: transform 0.3s ease; }
.gtd-filters { list-style: none; }
.gtd-filters li { padding: 12px 24px; cursor: pointer; color: var(--text-primary); display: flex; align-items: center; font-weight: 500; border-radius: 0 24px 24px 0; margin-right: 16px; }
.gtd-filters li:hover { background-color: var(--hover-overlay); }
.gtd-filters li.active { background-color: #feefc3; color: #b06000; }

.main-content { flex: 1; padding: 24px; overflow-y: auto; display: flex; flex-direction: column; }

/* Compose Area & Split Editor */
.compose-area { max-width: 800px; width: 100%; margin: 0 auto 32px auto; background: var(--surface-color); border-radius: 8px; box-shadow: 0 1px 2px 0 rgba(0,0,0,0.3); padding: 16px; display: flex; flex-direction: column; }
#noteTitle { border: none; outline: none; width: 100%; font-family: var(--font-family); font-size: 1.1rem; font-weight: 600; margin-bottom: 12px; background: transparent; color: var(--text-primary); }

.editor-split { display: flex; gap: 16px; min-height: 80px; }
.editor-split textarea { flex: 1; border: none; outline: none; font-family: var(--font-family); font-size: 1rem; resize: vertical; background: transparent; color: var(--text-primary); }
.markdown-preview { flex: 1; border-left: 1px dashed var(--border-color); padding-left: 16px; font-size: 0.95rem; line-height: 1.4; color: var(--text-primary); word-break: break-word; }
.markdown-preview.empty { color: var(--text-secondary); font-style: italic; }

.compose-actions { display: flex; justify-content: space-between; align-items: center; margin-top: 12px; gap: 10px; flex-wrap: wrap; }
.compose-actions select { border: 1px solid var(--border-color); background: var(--bg-color); color: var(--text-primary); border-radius: 4px; padding: 6px; cursor: pointer; }
.image-upload-btn { cursor: pointer; font-size: 1.2rem; }
#saveNoteBtn { background-color: var(--hover-overlay); border: none; color: var(--text-primary); font-weight: 600; padding: 8px 16px; border-radius: 4px; cursor: pointer; }

/* Custom 10-Color Palette */
.color-palette { display: flex; gap: 6px; }
.color-swatch { width: 24px; height: 24px; border-radius: 50%; cursor: pointer; border: 2px solid transparent; transition: transform 0.1s; }
.color-swatch:hover { transform: scale(1.1); }
.color-swatch.selected { border: 2px solid var(--text-primary); }

/* Kanban Board Layout (Drag & Drop) */
.board-container { display: flex; gap: 16px; overflow-x: auto; flex: 1; padding-bottom: 16px; }
.gtd-column { flex: 0 0 280px; display: flex; flex-direction: column; background: var(--bg-color); border-radius: 8px; padding: 12px; }
.column-header { font-size: 1rem; color: var(--text-secondary); margin-bottom: 12px; padding-left: 4px; }
.column-dropzone { flex: 1; min-height: 200px; display: flex; flex-direction: column; gap: 12px; border-radius: 8px; transition: background-color 0.2s; }
.column-dropzone.drag-over { background-color: var(--hover-overlay); outline: 2px dashed var(--accent-color); }

/* Note Cards */
.note-card { border-radius: 8px; padding: 16px; box-shadow: 0 1px 3px rgba(0,0,0,0.2); cursor: grab; position: relative; color: var(--card-text); transition: box-shadow 0.2s, transform 0.1s; }
.note-card:hover { box-shadow: 0 4px 10px rgba(0,0,0,0.3); }
.note-card:active { cursor: grabbing; transform: scale(0.98); }
.note-title { font-weight: 600; font-size: 1.1rem; margin-bottom: 8px; }
.note-body { font-size: 0.95rem; line-height: 1.4; max-height: 200px; overflow-y: hidden; }
.note-body img { max-width: 100%; border-radius: 4px; margin-top: 8px; }
.note-meta { font-size: 0.75rem; opacity: 0.7; margin-top: 12px; border-top: 1px solid rgba(0,0,0,0.1); padding-top: 8px; }
.pin-btn { position: absolute; top: 12px; right: 12px; background: none; border: none; cursor: pointer; opacity: 0.3; }
.note-card.pinned .pin-btn { opacity: 1; }

/* Modals */
.modal { display: none; position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.6); z-index: 100; align-items: center; justify-content: center; }
.modal.active { display: flex; }
.modal-content { background: var(--surface-color); padding: 24px; border-radius: 8px; width: 90%; max-width: 500px; box-shadow: 0 4px 20px rgba(0,0,0,0.3); }
.modal-large { max-width: 800px; }
.full-width { width: 100%; margin-bottom: 16px; padding: 12px; border: 1px solid var(--border-color); border-radius: 4px; background: var(--bg-color); color: var(--text-primary); }
.btn-primary { background-color: var(--accent-color); color: #fff; border: none; padding: 10px 16px; border-radius: 4px; cursor: pointer; }
.btn-danger { background-color: var(--danger-color); color: #fff; border: none; padding: 10px 16px; border-radius: 4px; cursor: pointer; }

@media (max-width: 768px) {
    .sidebar { position: fixed; z-index: 50; height: 100%; transform: translateX(-100%); }
    .sidebar.open { transform: translateX(0); }
    .editor-split { flex-direction: column; }
    .markdown-preview { border-left: none; border-top: 1px dashed var(--border-color); padding-left: 0; padding-top: 12px; }
}