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

:root {
    --paper: #f7f3eb;
    --paper-shadow: #e8e0d0;
    --pencil-dark: #2b2b2b;
    --pencil-mid: #5a5a5a;
    --pencil-light: #9a9a9a;
    --pencil-faint: #c8c3b8;
    --accent: #4a6cf7;
    --accent-light: rgba(74, 108, 247, 0.08);
    --accent-faint: rgba(74, 108, 247, 0.04);
    --danger: #d1453b;
    --sketch-radius: 255px 15px 225px 15px/15px 225px 15px 255px;
    --sketch-radius-sm: 55px 8px 75px 8px/8px 65px 8px 55px;
}

body {
    font-family: 'Source Sans 3', system-ui, -apple-system, sans-serif;
    background: var(--paper);
    background-image:
        repeating-linear-gradient(
            transparent,
            transparent 27px,
            rgba(160, 180, 200, 0.12) 27px,
            rgba(160, 180, 200, 0.12) 28px
        );
    color: var(--pencil-dark);
    height: 100vh;
    overflow: hidden;
    font-size: 18px;
    line-height: 1.6;
}

.app {
    display: flex;
    flex-direction: column;
    height: 100vh;
}

.documents-panel {
    flex-shrink: 0;
    display: flex;
    flex-direction: column;
    padding: 14px 24px 10px;
    border-bottom: 2px dashed var(--pencil-faint);
    position: relative;
    transition: border-color 0.3s;
}

.documents-panel.collapsed {
    border-bottom-color: transparent;
    padding-bottom: 0;
}

.documents-panel.collapsed::after {
    display: none;
}

.documents-panel::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 10%;
    right: 10%;
    height: 2px;
    background: var(--pencil-faint);
    opacity: 0.3;
}

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

.documents-panel h2 {
    font-size: 22px;
    font-weight: 600;
    color: var(--pencil-dark);
    display: flex;
    align-items: center;
    gap: 8px;
}

.toggle-btn {
    background: none;
    border: 2px solid var(--pencil-dark);
    border-radius: var(--sketch-radius-sm);
    cursor: pointer;
    padding: 2px 6px;
    display: flex;
    align-items: center;
    color: var(--pencil-dark);
    transition: all 0.2s;
    font-family: inherit;
    line-height: 1;
}

.toggle-btn:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.toggle-btn svg {
    width: 18px;
    height: 18px;
    transition: transform 0.3s;
}

.toggle-label {
    font-size: 18px;
    font-weight: 600;
    display: none;
}

.documents-panel.collapsed .toggle-label {
    display: inline;
}

.documents-panel.collapsed .toggle-btn svg {
    transform: rotate(180deg);
}

.documents-body {
    overflow: hidden;
    transition: height 0.35s ease;
}

.documents-panel h2 svg {
    stroke: var(--pencil-dark);
    stroke-width: 2.5;
}

.drop-zone {
    border: 2px dashed var(--pencil-mid);
    border-radius: var(--sketch-radius);
    padding: 20px 24px;
    text-align: center;
    cursor: pointer;
    transition: all 0.2s;
    background: var(--accent-faint);
    flex-shrink: 0;
    position: relative;
}

.drop-zone:hover,
.drop-zone.drag-over {
    border-color: var(--accent);
    background: var(--accent-light);
    border-style: dashed;
}

.drop-zone svg {
    width: 32px;
    height: 32px;
    color: var(--pencil-mid);
    margin-bottom: 4px;
    stroke-width: 2;
}

.drop-zone p {
    color: var(--pencil-mid);
    font-size: 18px;
}

.drop-zone .highlight {
    color: var(--accent);
    font-weight: 600;
    text-decoration: underline wavy var(--accent);
    text-underline-offset: 4px;
}

.drop-zone .formats {
    font-size: 14px;
    color: var(--pencil-dark);
    margin-top: 2px;
}

.doc-list {
    flex: 1;
    overflow-y: auto;
    margin-top: 10px;
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    align-content: flex-start;
}

.doc-list:empty::after {
    content: 'No documents yet — drop some files above ✏️';
    color: var(--pencil-dark);
    font-size: 36px;
    width: 100%;
    text-align: center;
    padding: 24px;
    opacity: 0.7;
}

.doc-card {
    background: var(--paper);
    border: 2px solid var(--pencil-dark);
    border-radius: var(--sketch-radius-sm);
    padding: 10px 14px;
    display: flex;
    align-items: center;
    gap: 10px;
    min-width: 180px;
    max-width: 240px;
    transition: all 0.15s;
    position: relative;
    box-shadow: 3px 3px 0 var(--pencil-faint);
}

.doc-card:hover {
    border-color: var(--accent);
    box-shadow: 3px 3px 0 rgba(74, 108, 247, 0.25);
    transform: translate(-1px, -1px);
}

.doc-card .icon {
    font-size: 24px;
    flex-shrink: 0;
    filter: grayscale(0.3);
}

.doc-card .info {
    flex: 1;
    min-width: 0;
}

.doc-card .name {
    font-size: 17px;
    font-weight: 600;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    color: var(--pencil-dark);
}

.doc-card .meta {
    font-size: 14px;
    color: var(--pencil-dark);
    margin-top: 0;
}

.doc-card .delete-btn {
    background: none;
    border: none;
    color: var(--pencil-dark);
    cursor: pointer;
    font-size: 18px;
    padding: 2px 6px;
    border-radius: 4px;
    transition: color 0.2s;
    flex-shrink: 0;
    font-family: inherit;
}

.doc-card .delete-btn:hover {
    color: var(--danger);
}

.loading-bar {
    height: 3px;
    background: repeating-linear-gradient(
        90deg,
        var(--pencil-dark) 0px,
        var(--pencil-dark) 2px,
        transparent 2px,
        transparent 4px
    );
    border-radius: 0;
    animation: pencilDraw 1.2s infinite linear;
    display: none;
    margin-top: 8px;
    width: 0;
}

.loading-bar.active {
    display: block;
    animation: pencilDraw 1.2s infinite linear;
}

@keyframes pencilDraw {
    0% { width: 0; opacity: 1; }
    60% { width: 70%; opacity: 0.9; }
    100% { width: 100%; opacity: 0.3; }
}

.chat-panel {
    flex: 1;
    min-height: 280px;
    display: flex;
    flex-direction: column;
    background: var(--paper);
    border-top: 2px dashed var(--pencil-faint);
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 14px 24px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.chat-empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 6px;
    margin: auto;
    opacity: 0.7;
}

.chat-messages:has(.message) .chat-empty-state {
    display: none;
}

.chat-empty-state svg {
    width: 40px;
    height: 40px;
    color: var(--pencil-dark);
    stroke-width: 2;
}

.chat-empty-state p {
    color: var(--pencil-dark);
    font-size: 36px;
}

.chat-empty-state .highlight {
    color: var(--accent);
    font-weight: 600;
    text-decoration: underline wavy var(--accent);
    text-underline-offset: 4px;
}

.message {
    max-width: 80%;
    padding: 10px 16px;
    font-size: 18px;
    line-height: 1.5;
    animation: sketchIn 0.25s ease-out;
}

@keyframes sketchIn {
    from { opacity: 0; transform: translateY(6px) scale(0.97); }
    to { opacity: 1; transform: translateY(0) scale(1); }
}

.message.user {
    background: transparent;
    border: 2px solid var(--pencil-dark);
    border-radius: 20px 20px 4px 20px;
    align-self: flex-end;
    color: var(--pencil-dark);
    box-shadow: 2px 2px 0 var(--pencil-faint);
}

.message.bot {
    background: transparent;
    border: 2px dashed var(--pencil-mid);
    border-radius: 20px 20px 20px 4px;
    align-self: flex-start;
    color: var(--pencil-dark);
}

.message.bot .sources {
    margin-top: 8px;
    padding-top: 8px;
    border-top: 1px dashed var(--pencil-faint);
    font-size: 15px;
    color: var(--pencil-dark);
}

.message.bot .sources span {
    display: inline-block;
    background: var(--paper);
    border: 1px solid var(--pencil-faint);
    border-radius: var(--sketch-radius-sm);
    padding: 1px 8px;
    margin: 2px 4px 2px 0;
    color: var(--pencil-mid);
    font-size: 14px;
}

.message.bot .sources strong {
    color: var(--accent);
    font-weight: 600;
}

.chat-input-area {
    padding: 10px 24px 14px;
    border-top: 1px dashed var(--pencil-faint);
    display: flex;
    gap: 10px;
    align-items: flex-end;
}

.chat-input-area textarea {
    flex: 1;
    background: transparent;
    border: 2px solid var(--pencil-dark);
    border-radius: var(--sketch-radius);
    padding: 10px 16px;
    color: var(--pencil-dark);
    font-size: 18px;
    font-family: inherit;
    resize: none;
    outline: none;
    max-height: 120px;
    min-height: 48px;
    transition: border-color 0.2s;
    line-height: 1.5;
}

.chat-input-area textarea:focus {
    border-color: var(--accent);
}

.chat-input-area textarea::placeholder {
    color: var(--pencil-dark);
    opacity: 0.7;
}

.send-btn {
    background: var(--pencil-dark);
    border: 2px solid var(--pencil-dark);
    border-radius: var(--sketch-radius-sm);
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: all 0.2s;
    flex-shrink: 0;
    box-shadow: 2px 2px 0 var(--pencil-faint);
}

.send-btn:hover {
    background: var(--accent);
    border-color: var(--accent);
    box-shadow: 2px 2px 0 rgba(74, 108, 247, 0.3);
    transform: translate(-1px, -1px);
}

.send-btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.send-btn svg {
    width: 22px;
    height: 22px;
    color: var(--paper);
    stroke-width: 2.5;
}

.toast {
    position: fixed;
    bottom: 24px;
    left: 50%;
    transform: translateX(-50%);
    background: var(--paper);
    border: 2px solid var(--pencil-dark);
    border-radius: var(--sketch-radius-sm);
    padding: 8px 20px;
    font-size: 17px;
    color: var(--pencil-dark);
    box-shadow: 4px 4px 0 var(--pencil-faint);
    display: none;
    z-index: 100;
    animation: sketchIn 0.2s ease-out;
}

.toast.show {
    display: block;
}

::-webkit-scrollbar {
    width: 8px;
}

::-webkit-scrollbar-track {
    background: transparent;
}

::-webkit-scrollbar-thumb {
    background: var(--pencil-faint);
    border: 1px solid var(--pencil-dark);
    border-radius: 10px;
}

::-webkit-scrollbar-thumb:hover {
    background: var(--pencil-dark);
}