/* ===== Split Screen Layout ===== */

body.split-screen-active .chat-container-main {
    overflow: hidden;
    justify-content: flex-start;
}

body.split-screen-active #chatArea {
    display: none !important;
}

body.split-screen-active #chatContainerWelcome {
    display: none !important;
}

body.split-screen-active #scrollToBottomBtn {
    display: none !important;
}

/* Contextual controls belong to an individual conversation. Keep the legacy
   main-chat controls out of split mode even when their own visibility managers
   update inline display styles after the split view has opened. */
body.split-screen-active #headerShareButton,
body.split-screen-active #headerCanvasButtonWrap,
body.split-screen-active #headerTempChatButton,
body.split-screen-active #headerSaveTempChatButton,
body.split-screen-active #headerDotsButton,
body.split-screen-active #headerDotsButtonDropdown {
    display: none !important;
}

/* The split conversation owns the contextual portion of the sticky app
   header. Global navigation remains above this layer at the two outer edges. */
.split-screen-main-header {
    display: none;
}

body.split-screen-active .main-container-header {
    isolation: isolate;
}

body.split-screen-active .main-header-leading,
body.split-screen-active .main-header-actions {
    position: relative;
    z-index: 2;
}

body.split-screen-active .split-screen-main-header {
    position: absolute;
    inset: 0;
    z-index: 1;
    display: grid;
    grid-template-columns: var(--split-left-percent, 50%) minmax(0, 1fr);
    min-width: 0;
    direction: ltr;
    pointer-events: none;
}

.split-screen-main-header-slot {
    min-width: 0;
    container-type: inline-size;
    container-name: split-panel;
    pointer-events: auto;
}

.split-screen-main-header-slot:first-child {
    border-right: 1px solid var(--border-color);
}

html[dir="rtl"] .split-screen-main-header-slot {
    direction: rtl;
}

.split-screen-main-header-slot > .split-screen-panel-header {
    width: 100%;
    height: 100%;
    min-height: var(--header-height);
    border-bottom: 0;
}

.split-screen-main-header-slot[data-split-header-panel="left"] > .split-screen-panel-header {
    padding-left: max(12px, var(--split-header-left-gutter, 12px));
}

.split-screen-main-header-slot[data-split-header-panel="right"] > .split-screen-panel-header {
    padding-right: max(12px, var(--split-header-right-gutter, 12px));
}

.split-screen-wrapper {
    display: none;
    flex: 1;
    flex-direction: row;
    min-height: 0;
    overflow: hidden;
    width: 100%;
    /* Keep physical left/right semantics stable in RTL locales. Individual
       panels restore the document writing direction below. */
    direction: ltr;
}

body.split-screen-active .split-screen-wrapper {
    display: flex;
}

/* ===== Panels ===== */

.split-screen-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
    overflow: hidden;
    position: relative;
    container-type: inline-size;
    container-name: split-panel;
    transition: box-shadow 0.15s ease;
}

html[dir="rtl"] .split-screen-panel {
    direction: rtl;
}

.split-screen-panel.is-send-target {
    box-shadow: inset 0 2px 0 var(--primary-color);
}

.split-chat-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    overflow-y: auto;
    padding: 20px;
    min-height: 0;
    container-type: inline-size;
    container-name: chat-files-layout;
}

.split-chat-area-container {
    display: flex;
    flex-direction: column;
    gap: 12px;
    width: 100%;
    max-width: 800px;
    margin: 0 auto;
}

.split-screen-panel-header {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    padding: 6px 12px;
    min-height: 46px;
    gap: 8px;
    flex-shrink: 0;
    background: var(--background);
}

.split-screen-panel-model {
    display: flex;
    align-items: center;
    gap: 8px;
    cursor: pointer;
    padding: 4px 8px;
    border-radius: 8px;
    transition: background-color 0.15s ease;
    position: relative;
    min-width: 0;
    max-width: min(320px, 58%);
    width: auto;
    border: 0;
    background: transparent;
    color: inherit;
}

.split-panel-thinking-control {
    position: relative;
    flex: 0 1 auto;
    min-width: 0;
}

.split-panel-thinking-control[hidden] {
    display: none !important;
}

.split-panel-thinking-button {
    max-width: 150px;
    height: 30px;
    padding-inline: 10px;
}

.split-panel-thinking-control .split-panel-thinking-dropdown {
    position: absolute;
    top: calc(100% + 6px);
    bottom: auto;
    left: 0;
    z-index: 100;
    transform-origin: top left;
}

.split-screen-panel-actions {
    display: flex;
    align-items: center;
    gap: 6px;
    margin-inline-start: auto;
    flex-shrink: 0;
}

.split-panel-actions-menu {
    position: relative;
    display: flex;
    align-items: center;
}

.split-screen-panel-menu-trigger {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border-radius: 8px;
    color: var(--text-color-secondary);
    transition: background-color 0.15s ease, color 0.15s ease;
}

.split-screen-panel-menu-trigger[aria-expanded="true"] {
    color: var(--text-color);
    background: var(--hover);
}

.split-panel-actions-dropdown {
    top: calc(100% + 6px);
    right: auto;
    inset-inline-end: 0;
    z-index: 120;
    width: min(230px, calc(100vw - 24px));
    max-height: min(440px, calc(100vh - 100px));
    overflow-y: auto;
    transform-origin: top right;
}

html[dir="rtl"] .split-panel-actions-dropdown {
    transform-origin: top left;
}

.split-panel-actions-dropdown [hidden],
.split-panel-download-heading[hidden] {
    display: none !important;
}

.split-panel-action-icon,
.split-panel-action-check {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    flex: 0 0 20px;
}

.split-panel-action-icon svg,
.split-panel-action-check svg {
    width: 18px;
    height: 18px;
}

.split-panel-action-check {
    margin-inline-start: auto;
    visibility: hidden;
}

.split-panel-temporary-action[aria-checked="true"] .split-panel-action-check {
    visibility: visible;
}

.split-panel-download-heading {
    padding: 8px 10px 4px;
    color: var(--text-color-tertiary);
    font-size: 11px;
    font-weight: 600;
}

@media (hover: hover) and (pointer: fine) {
    .split-screen-panel-model:hover,
    .split-screen-panel-menu-trigger:hover {
        background-color: var(--hover);
    }
}

.split-panel-model-caret {
    flex-shrink: 0;
    opacity: 0.5;
    transition: transform 0.15s ease;
}

.split-screen-panel-model.open .split-panel-model-caret {
    transform: rotate(180deg);
}

.split-panel-model-dropdown {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    z-index: 100;
    min-width: 240px;
    max-width: 320px;
    max-height: 360px;
    overflow-y: auto;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: 10px;
    box-shadow: 0 8px 24px rgba(0, 0, 0, 0.12);
    padding: 4px;
    margin-top: 4px;
}

.split-panel-model-dropdown.open {
    display: block;
}

.split-screen-panel-model-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 20px;
    height: 20px;
    flex-shrink: 0;
}

.split-screen-panel-model-icon svg {
    width: 20px;
    height: 20px;
}

.split-screen-panel-model-icon img {
    width: 20px;
    height: 20px;
    object-fit: contain;
    display: block;
    border-radius: 6px;
}

.split-screen-panel-model-name {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-color);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.split-screen-panel-close {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 28px;
    height: 28px;
    border-radius: 8px;
    color: var(--text-color-secondary, #64748b);
    flex-shrink: 0;
    transition: background-color 0.15s ease, color 0.15s ease;
}

@media (hover: hover) and (pointer: fine) {
    .split-screen-panel-close:hover {
        background-color: var(--hover);
        color: var(--text-color);
    }
}

.split-screen-panel-close svg {
    width: 16px;
    height: 16px;
}

.split-screen-panel-save {
    display: none;
    align-items: center;
    justify-content: center;
    gap: 4px;
    height: 28px;
    padding: 0 10px;
    border-radius: 9999px;
    color: var(--text-color-secondary, #64748b);
    flex-shrink: 0;
    font-size: 12px;
    transition: background-color 0.15s ease, color 0.15s ease;
}

@media (hover: hover) and (pointer: fine) {
    .split-screen-panel-save:hover {
        background: color-mix(in srgb, var(--primary-color, #3b82f6) 12%, transparent);
        color: var(--text-color);
    }
}

.split-screen-panel-save:disabled {
    opacity: 0.55;
    cursor: default;
    pointer-events: none;
}

.split-screen-panel-save svg {
    width: 14px;
    height: 14px;
}

/* Panel chat area */
.split-screen-panel .split-chat-area {
    flex: 1;
    width: 100%;
    overflow-y: auto;
    padding: 0 16px;
    display: flex;
    justify-content: center;
}

.split-screen-panel .split-chat-area-container {
    height: 100%;
    max-width: 100%;
    min-width: 0;
    width: 100%;
}

.split-screen-panel .split-chat-area-container::after {
    content: "";
    display: block;
    flex: 0 0 var(--chat-trailing-spacer-height);
    height: var(--chat-trailing-spacer-height);
}

/* Panel empty state */
.split-screen-panel-empty {
    display: flex;
    flex: 1;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 12px;
    padding: 20px;
    color: var(--text-color-secondary, #64748b);
    font-size: 13px;
    text-align: center;
    user-select: none;
    transition: opacity 0.15s ease;
}

/* Subtle rounded tile holding the empty-state icon */
.split-screen-panel-empty-icon {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border-radius: 12px;
    background: var(--hover, rgba(0, 0, 0, 0.04));
    color: var(--text-color-secondary, #64748b);
}

.split-screen-panel-empty p {
    max-width: 220px;
    line-height: 1.5;
    margin: 0;
}

@media (prefers-reduced-motion: reduce) {
    .split-screen-panel-empty {
        transition: none;
    }
}

body.app-reduced-animations .split-screen-panel-empty,
body.reduced-animations .split-screen-panel-empty {
    transition: none;
}

.split-screen-panel-status {
    position: absolute;
    inset: 0;
    z-index: 4;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 24px;
    color: var(--text-color-secondary);
    background: color-mix(in srgb, var(--background) 92%, transparent);
    font-size: 13px;
    text-align: center;
}

.split-screen-panel-status[hidden] {
    display: none;
}

.split-screen-panel.has-load-error .split-screen-panel-status {
    color: var(--error-color);
}

.split-screen-panel.has-chat .split-screen-panel-empty {
    display: none;
}

.split-screen-panel:not(.has-chat) .split-chat-area {
    display: none;
}

/* Panel scroll-to-bottom */
.split-screen-panel .split-scroll-to-bottom-btn {
    position: absolute;
    bottom: 12px;
    left: 50%;
    transform: translateX(-50%);
    z-index: 5;
    display: none;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    border-radius: 50%;
    background: var(--bg-normal-elevated, var(--background));
    border: 1px solid var(--border-color);
    box-shadow: 0 2px 6px var(--shadow-color, rgba(0,0,0,0.08));
    color: var(--text-color);
    cursor: pointer;
    transition: background-color 0.15s ease;
}

.split-screen-panel .split-scroll-to-bottom-btn.visible {
    display: flex;
}

@media (hover: hover) and (pointer: fine) {
    .split-screen-panel .split-scroll-to-bottom-btn:hover {
        background: linear-gradient(var(--hover), var(--hover)), var(--bg-normal-elevated, var(--background));
    }
}

.split-screen-panel .split-scroll-to-bottom-btn svg {
    width: 16px;
    height: 16px;
}

/* ===== Divider ===== */

.split-screen-divider {
    width: 1px;
    background: var(--border-color);
    flex-shrink: 0;
    position: relative;
    cursor: col-resize;
    z-index: 2;
    transition: background-color 0.15s ease;
    touch-action: none;
}

.split-screen-divider:focus-visible {
    background: var(--primary-color);
    outline: 2px solid var(--primary-color);
    outline-offset: 2px;
}

body.split-screen-resizing {
    cursor: col-resize;
    user-select: none;
}

.split-screen-divider::before {
    content: "";
    position: absolute;
    top: 0;
    left: -4px;
    right: -4px;
    bottom: 0;
    z-index: 1;
    transition: background-color 0.15s ease;
}

.split-screen-divider.dragging {
    background: var(--accent-color, #3b82f6);
}

@media (hover: hover) and (pointer: fine) {
    .split-screen-divider:hover {
        background: var(--accent-color, #3b82f6);
    }
}

.split-screen-divider.dragging::before {
    background: color-mix(in srgb, var(--accent-color, #3b82f6) 12%, transparent);
}

@media (hover: hover) and (pointer: fine) {
    .split-screen-divider:hover::before {
        background: color-mix(in srgb, var(--accent-color, #3b82f6) 12%, transparent);
    }
}

/* ===== Drop Zone ===== */

/* Full-panel drop overlay shown while a sidebar chat hovers a split panel.
   The overlay is pointer-events: none so the underlying panel keeps
   receiving the dragover/drop events. */
.split-panel-drop-overlay {
    position: absolute;
    inset: 8px;
    z-index: 7;
    display: none;
    align-items: center;
    justify-content: center;
    border-radius: 14px;
    border: 1.5px dashed color-mix(in srgb, var(--accent-color, #3b82f6) 70%, transparent);
    background: color-mix(in srgb, var(--accent-color, #3b82f6) 6%, transparent);
    backdrop-filter: blur(1.5px);
    -webkit-backdrop-filter: blur(1.5px);
    pointer-events: none;
    animation: split-drop-overlay-in 0.16s ease;
}

.split-screen-panel.drop-target .split-panel-drop-overlay {
    display: flex;
}

/* Floating pill card centered in the drop overlay */
.split-panel-drop-card {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 9px 16px;
    border-radius: 999px;
    background: var(--background);
    border: 1px solid var(--border-color);
    box-shadow: 0 8px 24px var(--shadow-color, rgba(0, 0, 0, 0.12));
    color: var(--text-color);
    font-size: 13px;
    font-weight: 500;
    white-space: nowrap;
    animation: split-drop-card-in 0.18s ease;
}

.split-panel-drop-card svg {
    flex-shrink: 0;
    color: var(--accent-color, #3b82f6);
}

/* Soften the empty-state hint while a drop overlay is visible so the
   overlay card is the single clear call to action. */
.split-screen-panel.drop-target .split-screen-panel-empty {
    opacity: 0.25;
}

/* ===== Drop onto open chat (enter split-screen) =====
   While dragging a chat over the open conversation, a two-half preview is
   shown. The hovered half highlights to indicate where the dropped chat
   will open. Positioned over the chat area only (top/height set by JS). */
.split-drop-preview {
    position: absolute;
    left: 0;
    right: 0;
    top: 0;
    z-index: 30;
    display: none;
    gap: 10px;
    padding: 10px 14px;
    pointer-events: none;
    animation: split-drop-overlay-in 0.16s ease;
}

#chatArea.drop-target-split + .split-drop-preview {
    display: flex;
}

.split-drop-preview-half {
    flex: 1;
    min-width: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 14px;
    border: 1.5px dashed color-mix(in srgb, var(--text-color-secondary, #64748b) 35%, transparent);
    background: color-mix(in srgb, var(--background) 45%, transparent);
    backdrop-filter: blur(1.5px);
    -webkit-backdrop-filter: blur(1.5px);
    opacity: 0.55;
    transition: opacity 0.15s ease, border-color 0.15s ease, background-color 0.15s ease;
}

.split-drop-preview-half .split-panel-drop-card {
    opacity: 0;
    transform: scale(0.94);
    animation: none;
    transition: opacity 0.15s ease, transform 0.15s ease;
}

/* Highlight the half the chat would open in */
#chatArea.drop-split-left + .split-drop-preview .split-drop-preview-half[data-drop-side="left"],
#chatArea.drop-split-right + .split-drop-preview .split-drop-preview-half[data-drop-side="right"] {
    opacity: 1;
    border-color: color-mix(in srgb, var(--accent-color, #3b82f6) 70%, transparent);
    background: color-mix(in srgb, var(--accent-color, #3b82f6) 7%, transparent);
}

#chatArea.drop-split-left + .split-drop-preview .split-drop-preview-half[data-drop-side="left"] .split-panel-drop-card,
#chatArea.drop-split-right + .split-drop-preview .split-drop-preview-half[data-drop-side="right"] .split-panel-drop-card {
    opacity: 1;
    transform: scale(1);
}

/* Reduced animations: drop feedback appears instantly, no motion */
@media (prefers-reduced-motion: reduce) {
    .split-panel-drop-overlay,
    .split-panel-drop-card,
    .split-drop-preview {
        animation: none;
    }
    .split-drop-preview-half,
    .split-drop-preview-half .split-panel-drop-card {
        transition: none;
        transform: none;
    }
}

body.app-reduced-animations .split-panel-drop-overlay,
body.app-reduced-animations .split-panel-drop-card,
body.app-reduced-animations .split-drop-preview,
body.reduced-animations .split-panel-drop-overlay,
body.reduced-animations .split-panel-drop-card,
body.reduced-animations .split-drop-preview {
    animation: none;
}

body.app-reduced-animations .split-drop-preview-half,
body.app-reduced-animations .split-drop-preview-half .split-panel-drop-card,
body.reduced-animations .split-drop-preview-half,
body.reduced-animations .split-drop-preview-half .split-panel-drop-card {
    transition: none;
    transform: none;
}

/* ===== Send Target Dropdown ===== */

.split-send-target-wrapper {
    display: none;
    position: relative;
}

body.split-screen-active .split-send-target-wrapper {
    display: flex;
}

.split-send-target-dropdown {
    position: absolute;
    bottom: calc(100% + 6px);
    left: 0;
    background: var(--background);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 4px;
    display: none;
    flex-direction: column;
    min-width: 120px;
    z-index: 20;
    box-shadow: 0 4px 12px var(--shadow-color, rgba(0,0,0,0.08));
}

.split-send-target-dropdown.open {
    display: flex;
}

.split-send-target-option {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 10px;
    border-radius: 8px;
    font-size: 13px;
    color: var(--text-color);
    cursor: pointer;
    transition: background-color 0.12s ease;
    white-space: nowrap;
    width: 100%;
    border: 0;
    background: transparent;
    text-align: start;
}

@media (hover: hover) and (pointer: fine) {
    .split-send-target-option:hover {
        background-color: var(--hover);
    }
}

.split-send-target-option.active {
    font-weight: 600;
    color: var(--accent-color, #3b82f6);
}

.split-send-target-current-icon,
.split-send-target-option-icon,
.split-settings-tab-icon {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.split-send-target-current-icon,
.split-send-target-option-icon {
    width: 16px;
    height: 16px;
}

.split-send-target-current-icon svg,
.split-send-target-option-icon svg {
    width: 16px;
    height: 16px;
}

/* ===== Toggle Button in Header ===== */

.split-screen-toggle-btn {
    display: flex;
    align-items: center;
    justify-content: center;
}

.split-screen-toggle-btn.active {
    background-color: color-mix(in srgb, var(--primary-color) 18%, transparent);
}

/* ===== Model Settings Panel Tabs ===== */

.split-settings-panel-tabs {
    display: flex;
    gap: 4px;
    padding: 4px 8px 6px;
    border-top: 1px solid var(--border-color);
    flex-shrink: 0;
}

.split-settings-tab {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    padding: 6px 12px;
    border-radius: 8px;
    font-size: 13px;
    font-weight: 500;
    color: var(--text-color-secondary, #64748b);
    background: transparent;
    border: 1px solid transparent;
    cursor: pointer;
    transition: background-color 0.15s ease, color 0.15s ease, border-color 0.15s ease;
}

@media (hover: hover) and (pointer: fine) {
    .split-settings-tab:hover {
        background-color: var(--hover);
    }
}

.split-settings-tab.active {
    color: var(--text-color);
    background-color: var(--hover);
    border-color: var(--border-color);
}

.split-settings-tab-icon {
    width: 16px;
    height: 16px;
}

.split-settings-tab-icon svg {
    width: 16px;
    height: 16px;
}

/* ===== Responsive ===== */

.split-compact-tabs[hidden] {
    display: none !important;
}

.split-compact-tabs {
    flex: 0 0 auto;
    gap: 4px;
    padding: 6px 8px;
    border-bottom: 1px solid var(--border-color);
    background: var(--background);
}

.split-compact-tab {
    flex: 1;
    min-width: 0;
    padding: 7px 12px;
    border: 1px solid transparent;
    border-radius: 8px;
    color: var(--text-color-secondary);
    background: transparent;
    font-size: 13px;
    font-weight: 600;
}

.split-compact-tab.active {
    color: var(--text-color);
    border-color: var(--border-color);
    background: var(--hover);
}

body.split-screen-compact .split-screen-wrapper {
    flex-direction: column;
}

body.split-screen-compact .split-screen-main-header {
    display: flex;
}

body.split-screen-compact .split-screen-main-header-slot {
    display: none;
}

body.split-screen-compact .split-screen-main-header-slot.compact-active {
    display: block;
    flex: 1 1 auto;
}

body.split-screen-compact .split-screen-main-header-slot.compact-active > .split-screen-panel-header {
    padding-left: max(12px, var(--split-header-left-gutter, 12px));
    padding-right: max(12px, var(--split-header-right-gutter, 12px));
}

body.split-screen-compact .split-compact-tabs {
    display: flex;
}

body.split-screen-compact .split-screen-panel:not(.compact-active),
body.split-screen-compact .split-screen-divider {
    display: none;
}

body.split-screen-compact .split-screen-panel.compact-active {
    display: flex;
    width: 100% !important;
    flex: 1 1 auto !important;
}

@container split-panel (max-width: 430px) {
    .split-screen-panel-header {
        gap: 5px;
        padding-inline: 8px;
    }

    .split-panel-thinking-button {
        max-width: 42px;
        padding-inline: 7px;
    }

    .split-panel-thinking-label,
    .split-screen-panel-save > span {
        display: none;
    }

    .split-screen-panel-save {
        width: 28px;
        padding-inline: 0;
    }

    .split-screen-panel-model {
        max-width: 34%;
        padding-inline: 5px;
    }
}

@container split-panel (max-width: 360px) {
    .split-screen-panel-model {
        max-width: 42px;
    }

    .split-screen-panel-model-name {
        display: none;
    }
}