/* =============================================================================
   3K Nanobana — Chat Interface Styles
   ============================================================================= */

/* ─── App Layout ───────────────────────────────────────────────────────────── */
#app {
    display: flex;
    height: 100vh;
    width: 100vw;
    overflow: hidden;
}

/* ─── Sidebar ──────────────────────────────────────────────────────────────── */
.sidebar {
    width: var(--sidebar-width);
    min-width: var(--sidebar-width);
    height: 100%;
    display: flex;
    flex-direction: column;
    background: var(--bg-secondary);
    border-right: 1px solid var(--border-subtle);
    transition: transform var(--transition-default);
    z-index: 100;
}

.sidebar-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border-subtle);
}

.sidebar-logo {
    display: flex;
    align-items: center;
    gap: 10px;
}
.sidebar-logo-icon {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--accent-primary), #a78bfa);
    border-radius: var(--radius-md);
    font-size: 18px;
}
.sidebar-logo-text {
    font-size: 16px;
    font-weight: 700;
    letter-spacing: -0.02em;
}
.sidebar-logo-sub {
    font-size: 10px;
    color: var(--text-tertiary);
    font-weight: 500;
    letter-spacing: 0.05em;
    text-transform: uppercase;
}

.sidebar-actions {
    padding: 12px 16px;
}

.btn-new-session {
    width: 100%;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 16px;
    background: linear-gradient(135deg, var(--accent-primary), #a78bfa);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    font-size: 13px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition-fast);
}
.btn-new-session:hover {
    filter: brightness(1.1);
    box-shadow: var(--shadow-glow);
}

/* Navigation Tabs */
.sidebar-nav {
    display: flex;
    gap: 2px;
    padding: 0 16px;
    margin-bottom: 8px;
}
.sidebar-nav-tab {
    flex: 1;
    padding: 8px 4px;
    font-size: 11px;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    color: var(--text-tertiary);
    background: transparent;
    border: none;
    border-bottom: 2px solid transparent;
    cursor: pointer;
    transition: all var(--transition-fast);
    text-align: center;
}
.sidebar-nav-tab.active {
    color: var(--accent-primary);
    border-bottom-color: var(--accent-primary);
}
.sidebar-nav-tab:hover:not(.active) {
    color: var(--text-secondary);
}

/* Session List */
.session-list {
    flex: 1;
    overflow-y: auto;
    padding: 8px;
}
.session-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 12px;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-bottom: 2px;
}
.session-item:hover {
    background: var(--bg-hover);
}
.session-item.active {
    background: var(--bg-elevated);
    border: 1px solid var(--border-default);
}
.session-item-thumb {
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    object-fit: cover;
    background: var(--bg-tertiary);
    flex-shrink: 0;
}
.session-item-info {
    flex: 1;
    min-width: 0;
}
.session-item-name {
    font-size: 13px;
    font-weight: 500;
    color: var(--text-primary);
}
.session-item-meta {
    font-size: 11px;
    color: var(--text-tertiary);
    margin-top: 2px;
}
.session-item-delete {
    opacity: 0;
    transition: opacity var(--transition-fast);
}
.session-item:hover .session-item-delete {
    opacity: 1;
}

/* ─── Main Content Area ────────────────────────────────────────────────────── */
.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    height: 100%;
    min-width: 0;
    background: var(--bg-primary);
}

/* Header Bar */
.main-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 24px;
    height: var(--header-height);
    min-height: var(--header-height);
    border-bottom: 1px solid var(--border-subtle);
    background: var(--bg-secondary);
}
.main-header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}
.main-header-title {
    font-size: 15px;
    font-weight: 600;
}
.main-header-right {
    display: flex;
    align-items: center;
    gap: 8px;
}

/* ─── Chat Workspace ───────────────────────────────────────────────────────── */
.chat-workspace {
    flex: 1;
    display: flex;
    min-height: 0;
}

/* Chat Area */
.chat-area {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.chat-messages {
    flex: 1;
    overflow-y: auto;
    padding: 24px;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

/* Welcome/Empty State */
.chat-empty {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
}
.chat-empty-content {
    text-align: center;
    max-width: 480px;
    padding: 40px;
}
.chat-empty-icon {
    font-size: 64px;
    margin-bottom: 16px;
    filter: grayscale(0.3);
}
.chat-empty-title {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--accent-primary), var(--accent-secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}
.chat-empty-desc {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* Message Bubbles */
.message {
    display: flex;
    gap: 12px;
    max-width: 85%;
    animation: fadeInUp 0.3s ease-out;
}
.message.user {
    align-self: flex-end;
    flex-direction: row-reverse;
}
.message.assistant {
    align-self: flex-start;
}

.message-avatar {
    width: 32px;
    height: 32px;
    border-radius: var(--radius-full);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    flex-shrink: 0;
}
.message.user .message-avatar {
    background: var(--accent-primary);
}
.message.assistant .message-avatar {
    background: linear-gradient(135deg, #ffd166, #ff9f43);
}

.message-content {
    padding: 12px 16px;
    border-radius: var(--radius-lg);
    max-width: 100%;
}
.message.user .message-content {
    background: var(--accent-primary);
    color: white;
    border-bottom-right-radius: 4px;
}
.message.assistant .message-content {
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-bottom-left-radius: 4px;
}

.message-text {
    font-size: 14px;
    line-height: 1.6;
    word-wrap: break-word;
}

.message-image {
    margin-top: 8px;
    border-radius: var(--radius-md);
    overflow: hidden;
    position: relative;
}
.message-image img {
    max-width: 100%;
    max-height: 500px;
    display: block;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: transform var(--transition-fast);
}
.message-image img:hover {
    transform: scale(1.02);
}

.message-actions {
    display: flex;
    gap: 6px;
    margin-top: 8px;
    flex-wrap: wrap;
}

.message-version-badge {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    padding: 3px 8px;
    font-size: 11px;
    font-weight: 600;
    background: var(--accent-glow);
    color: var(--accent-primary);
    border-radius: var(--radius-full);
}

.message-timestamp {
    font-size: 10px;
    color: var(--text-tertiary);
    margin-top: 4px;
}

/* Typing Indicator */
.typing-indicator {
    display: flex;
    align-items: center;
    gap: 6px;
    padding: 12px 16px;
    background: var(--bg-elevated);
    border: 1px solid var(--border-subtle);
    border-radius: var(--radius-lg);
    border-bottom-left-radius: 4px;
    max-width: 100px;
}
.typing-dot {
    width: 8px;
    height: 8px;
    background: var(--text-tertiary);
    border-radius: 50%;
    animation: pulse 1.4s ease-in-out infinite both;
}
.typing-dot:nth-child(1) { animation-delay: 0s; }
.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

/* ─── Chat Input Bar ──────────────────────────────────────────────────────── */
.chat-input-bar {
    padding: 16px 24px;
    border-top: 1px solid var(--border-subtle);
    background: var(--bg-secondary);
}

.chat-input-container {
    display: flex;
    align-items: flex-end;
    gap: 12px;
    background: var(--bg-tertiary);
    border: 1px solid var(--border-default);
    border-radius: var(--radius-lg);
    padding: 8px 12px;
    transition: border-color var(--transition-fast);
}
.chat-input-container:focus-within {
    border-color: var(--accent-primary);
    box-shadow: 0 0 0 3px var(--accent-glow);
}

.chat-input-tools {
    display: flex;
    gap: 4px;
    align-items: center;
    padding-bottom: 2px;
}

.chat-input {
    flex: 1;
    background: transparent;
    border: none;
    color: var(--text-primary);
    font-size: 14px;
    line-height: 1.5;
    resize: none;
    outline: none;
    min-height: 24px;
    max-height: 160px;
    font-family: var(--font-sans);
}
.chat-input::placeholder {
    color: var(--text-tertiary);
}

.chat-send-btn {
    width: 36px;
    height: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--accent-primary);
    color: white;
    border: none;
    border-radius: var(--radius-md);
    cursor: pointer;
    transition: all var(--transition-fast);
    flex-shrink: 0;
}
.chat-send-btn:hover {
    background: var(--accent-primary-hover);
    box-shadow: var(--shadow-glow);
}
.chat-send-btn:disabled {
    opacity: 0.3;
    cursor: not-allowed;
}

/* Upload Preview */
.upload-preview {
    display: flex;
    gap: 8px;
    padding-bottom: 8px;
    flex-wrap: wrap;
    display: none;
}
.upload-preview.active {
    display: flex;
}
.upload-preview-item {
    position: relative;
    width: 64px;
    height: 64px;
    border-radius: var(--radius-sm);
    overflow: hidden;
}
.upload-preview-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.upload-preview-remove {
    position: absolute;
    top: 2px;
    right: 2px;
    width: 18px;
    height: 18px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(0, 0, 0, 0.7);
    color: white;
    border: none;
    border-radius: 50%;
    font-size: 10px;
    cursor: pointer;
}

/* Reference Image Preview Strip */
.ref-preview {
    display: none;
    gap: 8px;
    padding: 8px 0;
    overflow-x: auto;
    align-items: center;
}
.ref-preview.active {
    display: flex;
}
.ref-preview-label {
    font-size: 11px;
    font-weight: 600;
    color: var(--accent-secondary);
    white-space: nowrap;
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 4px 10px;
    background: rgba(167, 139, 250, 0.12);
    border-radius: var(--radius-full);
    flex-shrink: 0;
}
.ref-preview-item {
    position: relative;
    width: 56px;
    height: 56px;
    border-radius: var(--radius-sm);
    overflow: hidden;
    border: 2px solid var(--accent-secondary);
    flex-shrink: 0;
    transition: transform var(--transition-fast);
}
.ref-preview-item:hover {
    transform: scale(1.08);
}
.ref-preview-item img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}
.ref-preview-item .upload-preview-remove {
    background: rgba(239, 68, 68, 0.85);
}
.ref-preview-clear {
    font-size: 11px;
    color: var(--text-tertiary);
    background: none;
    border: 1px solid var(--border-default);
    border-radius: var(--radius-sm);
    padding: 4px 8px;
    cursor: pointer;
    white-space: nowrap;
    transition: all var(--transition-fast);
    flex-shrink: 0;
}
.ref-preview-clear:hover {
    color: var(--danger);
    border-color: var(--danger);
}

/* Drag & Drop Overlay */
.drop-overlay {
    position: fixed;
    inset: 0;
    background: rgba(10, 11, 20, 0.9);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 10000;
}
.drop-overlay.active {
    display: flex;
}
.drop-overlay-content {
    text-align: center;
    padding: 60px;
    border: 3px dashed var(--accent-primary);
    border-radius: var(--radius-xl);
    animation: glow-pulse 2s infinite;
}
.drop-overlay-icon {
    font-size: 64px;
    margin-bottom: 16px;
}
.drop-overlay-text {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
}

/* ─── Image Lightbox ───────────────────────────────────────────────────────── */
.lightbox {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.92);
    display: none;
    align-items: center;
    justify-content: center;
    z-index: 10001;
    cursor: pointer;
}
.lightbox.active {
    display: flex;
    animation: fadeIn 0.2s ease;
}
.lightbox img {
    max-width: 90vw;
    max-height: 90vh;
    object-fit: contain;
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-xl);
}
.lightbox-close {
    position: absolute;
    top: 20px;
    right: 20px;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: rgba(255, 255, 255, 0.1);
    border: none;
    border-radius: 50%;
    color: white;
    font-size: 20px;
    cursor: pointer;
}