/* ============================================
   THƯ NỘI BỘ - Internal Mail System
   Premium Corporate White Theme v2.0
   Author: muathemewpgiare.com
   ============================================ */

/* === DESIGN TOKENS === */
:root {
    --tnb-white: #FFFFFF;
    --tnb-bg: #F7F8FA;
    --tnb-bg-light: #F1F5F9;
    --tnb-bg-hover: #EFF6FF;
    --tnb-border: #E2E8F0;
    --tnb-border-light: #F0F2F5;
    --tnb-text-primary: #1A1D23;
    --tnb-text-secondary: #5E6C84;
    --tnb-text-muted: #8993A4;
    --tnb-accent: #2563EB;
    --tnb-accent-light: #EFF6FF;
    --tnb-accent-hover: #1D4ED8;
    --tnb-accent-soft: #DBEAFE;
    --tnb-success: #059669;
    --tnb-success-light: #ECFDF5;
    --tnb-danger: #DC2626;
    --tnb-danger-light: #FEF2F2;
    --tnb-warning: #D97706;
    --tnb-warning-light: #FFFBEB;
    --tnb-shadow-xs: 0 1px 2px rgba(0,0,0,0.03);
    --tnb-shadow-sm: 0 1px 3px rgba(0,0,0,0.05), 0 1px 2px rgba(0,0,0,0.03);
    --tnb-shadow: 0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
    --tnb-shadow-md: 0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.05);
    --tnb-shadow-lg: 0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.05);
    --tnb-radius: 8px;
    --tnb-radius-lg: 12px;
    --tnb-radius-xl: 16px;
    --tnb-sidebar-width: 380px;
    --tnb-info-width: 320px;
    --tnb-transition: all 0.2s cubic-bezier(0.4, 0, 0.2, 1);
    --tnb-transition-fast: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
    --tnb-font: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
}

/* === MAIN LAYOUT === */
.tnb-page {
    background: var(--tnb-bg) !important;
    padding: 0 !important;
    margin: 0 !important;
    height: calc(100vh - 60px);
    overflow: hidden;
}

.tnb-container {
    display: flex;
    height: 100%;
    min-height: 0;
    background: var(--tnb-white);
    overflow: hidden;
    font-family: var(--tnb-font);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* === LEFT SIDEBAR === */
.tnb-sidebar-left {
    width: var(--tnb-sidebar-width);
    min-width: var(--tnb-sidebar-width);
    border-right: 1px solid var(--tnb-border);
    display: flex;
    flex-direction: column;
    background: var(--tnb-white);
    transition: var(--tnb-transition);
    position: relative;
    z-index: 10;
}

.tnb-sidebar-header {
    padding: 20px 20px 12px;
    flex-shrink: 0;
}

.tnb-title-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
}

.tnb-title {
    font-size: 18px;
    font-weight: 700;
    color: var(--tnb-text-primary);
    margin: 0;
    display: flex;
    align-items: center;
    gap: 10px;
    letter-spacing: -0.3px;
}

.tnb-btn-compose {
    width: 36px;
    height: 36px;
    border-radius: var(--tnb-radius);
    border: none;
    background: var(--tnb-accent);
    color: var(--tnb-white);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--tnb-transition);
    box-shadow: 0 1px 3px rgba(37,99,235,0.3);
}

.tnb-btn-compose:hover {
    background: var(--tnb-accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 4px 12px rgba(37,99,235,0.35);
}

/* Search */
.tnb-search-box {
    position: relative;
    margin-bottom: 12px;
}

.tnb-search-icon {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--tnb-text-muted);
    pointer-events: none;
}

.tnb-search-input {
    width: 100%;
    padding: 10px 14px 10px 38px;
    border: 1.5px solid var(--tnb-border);
    border-radius: var(--tnb-radius);
    font-size: 13.5px;
    color: var(--tnb-text-primary);
    background: var(--tnb-bg);
    transition: var(--tnb-transition);
    outline: none;
    font-family: var(--tnb-font);
}

.tnb-search-input:focus {
    border-color: var(--tnb-accent);
    background: var(--tnb-white);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

.tnb-search-input::placeholder {
    color: var(--tnb-text-muted);
}

/* Tabs */
.tnb-tabs {
    display: flex;
    gap: 2px;
    margin-bottom: 10px;
    background: var(--tnb-bg);
    border-radius: var(--tnb-radius);
    padding: 3px;
}

.tnb-tab {
    flex: 1;
    padding: 7px 12px;
    border: none;
    background: transparent;
    color: var(--tnb-text-secondary);
    font-size: 12.5px;
    font-weight: 600;
    cursor: pointer;
    border-radius: 6px;
    transition: var(--tnb-transition-fast);
    font-family: var(--tnb-font);
    white-space: nowrap;
}

.tnb-tab:hover {
    color: var(--tnb-text-primary);
    background: var(--tnb-white);
}

.tnb-tab.active {
    background: var(--tnb-accent);
    color: var(--tnb-white);
    box-shadow: 0 1px 3px rgba(37,99,235,0.25);
}

/* Label Filter */
.tnb-label-filter { margin-top: 2px; }

.tnb-label-select {
    width: 100%;
    padding: 6px 10px;
    border: 1.5px solid var(--tnb-border);
    border-radius: 6px;
    font-size: 12.5px;
    color: var(--tnb-text-secondary);
    background: var(--tnb-white);
    outline: none;
    cursor: pointer;
    font-family: var(--tnb-font);
}

/* Thread List */
.tnb-thread-list {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    scroll-behavior: smooth;
}

.tnb-thread-list::-webkit-scrollbar { width: 4px; }
.tnb-thread-list::-webkit-scrollbar-track { background: transparent; }
.tnb-thread-list::-webkit-scrollbar-thumb { background: var(--tnb-border); border-radius: 4px; }

.tnb-thread-item {
    display: flex;
    align-items: flex-start;
    padding: 14px 20px;
    gap: 12px;
    cursor: pointer;
    border-bottom: 1px solid var(--tnb-border-light);
    transition: var(--tnb-transition-fast);
    position: relative;
}

.tnb-thread-item:hover { background: var(--tnb-bg-hover); }

.tnb-thread-item.active {
    background: var(--tnb-accent-light);
    border-left: 3px solid var(--tnb-accent);
    padding-left: 17px;
}

.tnb-thread-item.unread { background: var(--tnb-white); }

.tnb-thread-item.unread .tnb-thread-subject {
    font-weight: 700;
    color: var(--tnb-text-primary);
}

.tnb-thread-item.unread::before {
    content: '';
    position: absolute;
    left: 7px;
    top: 50%;
    transform: translateY(-50%);
    width: 7px;
    height: 7px;
    border-radius: 50%;
    background: var(--tnb-accent);
    box-shadow: 0 0 0 2px rgba(37,99,235,0.2);
}

.tnb-thread-avatar { flex-shrink: 0; }

.tnb-thread-avatar img {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    object-fit: cover;
    border: 2px solid var(--tnb-border-light);
}

.tnb-thread-info { flex: 1; min-width: 0; overflow: hidden; }

.tnb-thread-top-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 3px;
}

.tnb-thread-subject {
    font-size: 13.5px;
    font-weight: 500;
    color: var(--tnb-text-primary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    flex: 1;
    line-height: 1.4;
}

.tnb-thread-time {
    font-size: 11px;
    color: var(--tnb-text-muted);
    white-space: nowrap;
    margin-left: 10px;
    flex-shrink: 0;
}

.tnb-thread-preview {
    font-size: 12.5px;
    color: var(--tnb-text-secondary);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    line-height: 1.4;
    margin-top: 2px;
}

.tnb-thread-bottom-row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-top: 5px;
}

.tnb-thread-label {
    display: inline-block;
    font-size: 10px;
    font-weight: 600;
    padding: 2px 7px;
    border-radius: 4px;
    text-transform: uppercase;
    letter-spacing: 0.4px;
}

.tnb-thread-icons { display: flex; align-items: center; gap: 6px; }
.tnb-thread-flag { color: var(--tnb-danger); }
.tnb-thread-pin { color: var(--tnb-accent); }
.tnb-thread-count {
    font-size: 10px;
    color: var(--tnb-text-muted);
    background: var(--tnb-bg);
    padding: 0 6px;
    border-radius: 10px;
    line-height: 18px;
    font-weight: 600;
}

.tnb-no-threads {
    text-align: center;
    padding: 50px 20px;
    color: var(--tnb-text-muted);
}
.tnb-no-threads i { margin-bottom: 12px; opacity: 0.25; }

/* === MAIN CONTENT === */
.tnb-main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    background: var(--tnb-white);
    overflow: hidden;
    min-width: 0;
    min-height: 0;
    position: relative;
}

#tnb-thread-detail {
    flex: 1;
    min-height: 0;
    overflow: hidden;
}

.tnb-empty-state {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    flex: 1;
    min-height: 0;
    padding: 40px;
    text-align: center;
}

.tnb-empty-illustration { margin-bottom: 24px; opacity: 0.7; }

.tnb-empty-title {
    font-size: 20px;
    font-weight: 700;
    color: var(--tnb-text-primary);
    margin-bottom: 8px;
    letter-spacing: -0.3px;
}

.tnb-empty-text {
    font-size: 14px;
    color: var(--tnb-text-muted);
    max-width: 420px;
    line-height: 1.6;
}

/* Thread Detail */
.tnb-detail-container {
    display: flex;
    flex-direction: column;
    height: 100%;
    min-height: 0;
    overflow: hidden;
    background: linear-gradient(180deg, #ffffff 0%, #f8fbff 100%);
}

.tnb-detail-header {
    padding: 18px 24px;
    border-bottom: 1px solid var(--tnb-border-light);
    flex-shrink: 0;
    background: rgba(255, 255, 255, 0.92);
    backdrop-filter: blur(10px);
    position: sticky;
    top: 0;
    z-index: 5;
}

.tnb-detail-header-top {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 16px;
}

.tnb-detail-subject-row {
    display: flex;
    align-items: center;
    gap: 10px;
    flex: 1;
    min-width: 0;
    flex-wrap: wrap;
}

.tnb-detail-subject {
    font-size: 20px;
    font-weight: 700;
    color: var(--tnb-text-primary);
    margin: 0;
    line-height: 1.3;
    letter-spacing: -0.3px;
}

.tnb-detail-actions {
    display: flex;
    align-items: center;
    gap: 2px;
    flex-shrink: 0;
}

.tnb-action-btn {
    width: 34px;
    height: 34px;
    border: none;
    background: transparent;
    color: var(--tnb-text-secondary);
    cursor: pointer;
    border-radius: var(--tnb-radius);
    display: flex;
    align-items: center;
    justify-content: center;
    transition: var(--tnb-transition-fast);
}

.tnb-action-btn:hover { background: var(--tnb-bg); color: var(--tnb-text-primary); }
.tnb-flag-btn.flagged { color: var(--tnb-danger); background: var(--tnb-danger-light); }
.tnb-pin-btn.pinned { color: var(--tnb-accent); background: var(--tnb-accent-light); }

/* Dropdown */
.tnb-dropdown { position: relative; }
.tnb-dropdown-menu {
    display: none; position: absolute; right: 0; top: 100%;
    background: var(--tnb-white); border: 1px solid var(--tnb-border);
    border-radius: var(--tnb-radius); box-shadow: var(--tnb-shadow-md);
    min-width: 180px; z-index: 100; padding: 6px 0;
}
.tnb-dropdown.open .tnb-dropdown-menu { display: block; }
.tnb-dropdown-item {
    display: flex; align-items: center; gap: 8px;
    padding: 9px 16px; font-size: 13px; color: var(--tnb-text-primary);
    text-decoration: none; transition: var(--tnb-transition-fast);
}
.tnb-dropdown-item:hover { background: var(--tnb-danger-light); color: var(--tnb-danger); text-decoration: none; }

/* Participants strip */
.tnb-participants-strip {
    display: flex; align-items: center; gap: 8px;
    margin-top: 10px; font-size: 12.5px; color: var(--tnb-text-secondary);
}
.tnb-participants-names { white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }

/* Labels */
.tnb-label {
    display: inline-flex; align-items: center;
    font-size: 11px; font-weight: 600; padding: 3px 10px;
    border-radius: 20px; text-transform: uppercase; letter-spacing: 0.3px;
}

.tnb-label-thong_bao, .tnb-thread-label-thong_bao { background: #DBEAFE; color: #1E40AF; }
.tnb-label-bao_cao, .tnb-thread-label-bao_cao { background: #D1FAE5; color: #065F46; }
.tnb-label-don_tu, .tnb-thread-label-don_tu { background: #FEF3C7; color: #92400E; }
.tnb-label-noi_quy, .tnb-thread-label-noi_quy { background: #FCE7F3; color: #9D174D; }
.tnb-label-hop, .tnb-thread-label-hop { background: #EDE9FE; color: #5B21B6; }
.tnb-label-khac, .tnb-thread-label-khac { background: var(--tnb-bg); color: var(--tnb-text-secondary); }

.tnb-pin-badge { color: var(--tnb-accent); }

/* === MESSAGES AREA === */
.tnb-messages-area {
    flex: 1;
    min-height: 0;
    overflow-y: auto;
    padding: 20px 24px 28px;
    background: linear-gradient(180deg, #f8fbff 0%, #f4f7fb 100%);
    scroll-behavior: smooth;
    overscroll-behavior: contain;
    scrollbar-gutter: stable;
}

.tnb-messages-area::-webkit-scrollbar { width: 7px; }
.tnb-messages-area::-webkit-scrollbar-thumb {
    background: #cfd8e3;
    border-radius: 999px;
    border: 2px solid transparent;
    background-clip: padding-box;
}

.tnb-message-item {
    display: flex; gap: 12px; margin-bottom: 20px;
    animation: tnbFadeIn 0.3s ease;
    align-items: flex-start;
}

@keyframes tnbFadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.tnb-message-own {
    flex-direction: row-reverse;
}

.tnb-message-avatar { flex-shrink: 0; padding-top: 2px; }
.tnb-message-own .tnb-message-avatar { margin-left: 4px; }
.tnb-message-other .tnb-message-avatar { margin-right: 4px; }

.tnb-avatar-md { width: 38px; height: 38px; border-radius: 50%; object-fit: cover; box-shadow: var(--tnb-shadow-xs); }
.tnb-avatar-sm { width: 32px; height: 32px; border-radius: 50%; object-fit: cover; }
.tnb-avatar-xs { width: 26px; height: 26px; border-radius: 50%; object-fit: cover; }

.tnb-message-body {
    flex: 1; min-width: 0; max-width: 80%;
    background: var(--tnb-white); border-radius: 18px;
    padding: 14px 18px; box-shadow: var(--tnb-shadow-sm);
    border: 1px solid var(--tnb-border-light); position: relative;
}

.tnb-message-own .tnb-message-body {
    background: linear-gradient(135deg, #eef4ff 0%, #e0ecff 100%);
    border-color: #bfd5ff;
    box-shadow: 0 10px 24px rgba(37, 99, 235, 0.10);
}

.tnb-message-other .tnb-message-body {
    background: #ffffff;
}

.tnb-message-meta {
    display: flex; align-items: center; gap: 8px;
    margin-bottom: 8px; flex-wrap: wrap;
}

.tnb-message-person {
    display: inline-flex; align-items: center; gap: 8px; flex-wrap: wrap;
}

.tnb-message-own .tnb-message-meta {
    justify-content: flex-end;
}

.tnb-message-author { font-size: 13.5px; font-weight: 700; color: var(--tnb-text-primary); }
.tnb-message-badge {
    display: inline-flex; align-items: center; padding: 3px 8px;
    border-radius: 999px; font-size: 10.5px; font-weight: 700; letter-spacing: .2px;
}
.tnb-message-badge-own {
    color: #1d4ed8; background: rgba(37, 99, 235, 0.12);
}
.tnb-message-badge-other {
    color: #0f766e; background: rgba(13, 148, 136, 0.12);
}
.tnb-message-role { font-size: 11px; color: var(--tnb-text-muted); background: var(--tnb-bg); padding: 2px 8px; border-radius: 999px; font-weight: 500; }
.tnb-message-time { font-size: 11px; color: var(--tnb-text-muted); margin-left: auto; }
.tnb-message-own .tnb-message-time { margin-left: 0; }

.tnb-message-content {
    font-size: 14px; color: var(--tnb-text-primary); line-height: 1.7;
    word-wrap: break-word; overflow-wrap: break-word;
}

.tnb-message-own .tnb-message-content {
    color: #0f172a;
}

.tnb-message-content p { margin: 0 0 8px 0; }
.tnb-message-content p:last-child { margin-bottom: 0; }
.tnb-message-content strong, .tnb-message-content b { color: var(--tnb-accent-hover); }
.tnb-message-content ul, .tnb-message-content ol { margin: 6px 0; padding-left: 20px; }
.tnb-message-content img { max-width: 100%; border-radius: 12px; margin: 8px 0; box-shadow: 0 6px 20px rgba(15,23,42,0.08); }
.tnb-message-content a { color: var(--tnb-accent); text-decoration: underline; }
.tnb-message-content blockquote {
    border-left: 3px solid var(--tnb-accent);
    padding-left: 12px; margin: 8px 0;
    color: var(--tnb-text-secondary); font-style: italic;
}

/* Message Actions */
.tnb-message-actions-menu { position: relative; display: inline-flex; }
.tnb-msg-action-btn {
    width: 26px; height: 26px; border: none; background: transparent;
    color: var(--tnb-text-muted); cursor: pointer; border-radius: 4px;
    display: flex; align-items: center; justify-content: center;
    opacity: 0; transition: var(--tnb-transition-fast);
}
.tnb-message-item:hover .tnb-msg-action-btn { opacity: 1; }
.tnb-msg-action-btn:hover { background: var(--tnb-bg); color: var(--tnb-text-primary); }

.tnb-msg-dropdown {
    display: none; position: absolute; right: 0; top: 100%;
    background: var(--tnb-white); border: 1px solid var(--tnb-border);
    border-radius: 6px; box-shadow: var(--tnb-shadow-md);
    min-width: 130px; z-index: 50; padding: 4px 0;
}
.tnb-msg-dropdown.show { display: block; }
.tnb-msg-dropdown-item {
    display: flex; align-items: center; gap: 6px;
    padding: 7px 14px; font-size: 12px; color: var(--tnb-danger);
    text-decoration: none; transition: var(--tnb-transition-fast);
}
.tnb-msg-dropdown-item:hover { background: var(--tnb-danger-light); text-decoration: none; color: var(--tnb-danger); }

/* Image & File Attachments */
.tnb-message-images {
    margin-top: 12px;
    display: grid;
    grid-template-columns: 1fr;
    gap: 8px;
}

.tnb-message-images-grid {
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
}

.tnb-image-attachment {
    display: block;
    overflow: hidden;
    border-radius: 14px;
    border: 1px solid var(--tnb-border-light);
    background: #f8fafc;
    box-shadow: 0 6px 18px rgba(15, 23, 42, 0.06);
}

.tnb-image-attachment img {
    display: block;
    width: 100%;
    max-height: 260px;
    object-fit: cover;
}

.tnb-message-files { margin-top: 12px; display: flex; flex-wrap: wrap; gap: 6px; }

.tnb-file-attachment {
    display: inline-flex; align-items: center; gap: 5px;
    padding: 6px 12px; background: var(--tnb-bg); border-radius: 999px;
    color: var(--tnb-accent); font-size: 12px; text-decoration: none;
    border: 1px solid var(--tnb-border); transition: var(--tnb-transition-fast); font-weight: 500;
}
.tnb-file-attachment:hover {
    background: var(--tnb-accent-light); text-decoration: none;
    color: var(--tnb-accent-hover); border-color: var(--tnb-accent-soft);
}

/* === REPLY BOX === */
.tnb-reply-box {
    padding: 16px 24px;
    border-top: 1px solid var(--tnb-border);
    background: rgba(255, 255, 255, 0.96);
    backdrop-filter: blur(12px);
    flex-shrink: 0;
    position: sticky;
    bottom: 0;
    z-index: 6;
    box-shadow: 0 -10px 25px rgba(15, 23, 42, 0.06);
}

.tnb-reply-editor-container { display: flex; gap: 12px; align-items: flex-start; }
.tnb-reply-avatar { flex-shrink: 0; margin-top: 6px; }

.tnb-reply-input-wrapper {
    flex: 1; border: 1.5px solid var(--tnb-border);
    border-radius: var(--tnb-radius-lg); transition: var(--tnb-transition);
    overflow: hidden; background: var(--tnb-white);
}

.tnb-reply-input-wrapper:focus-within {
    border-color: var(--tnb-accent);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

.tnb-reply-actions {
    display: flex; align-items: center; justify-content: space-between;
    padding: 8px 12px; background: var(--tnb-bg); border-top: 1px solid var(--tnb-border-light);
}

.tnb-reply-actions-left { display: flex; gap: 4px; }

/* Summernote inside reply */
.tnb-reply-input-wrapper .note-editor { border: none !important; box-shadow: none !important; }
.tnb-reply-input-wrapper .note-toolbar {
    background: var(--tnb-bg) !important;
    border-bottom: 1px solid var(--tnb-border-light) !important;
    padding: 4px 8px !important;
}
.tnb-reply-input-wrapper .note-editable {
    min-height: 80px !important; max-height: 200px !important;
    padding: 12px 16px !important; font-size: 14px !important;
    line-height: 1.6 !important; color: var(--tnb-text-primary) !important;
    font-family: var(--tnb-font) !important;
}
.tnb-reply-input-wrapper .note-statusbar { display: none !important; }

.tnb-toolbar-btn {
    width: 32px; height: 32px; border: none; background: transparent;
    color: var(--tnb-text-secondary); cursor: pointer; border-radius: 6px;
    display: flex; align-items: center; justify-content: center;
    transition: var(--tnb-transition-fast);
}
.tnb-toolbar-btn:hover { background: var(--tnb-white); color: var(--tnb-accent); }

.tnb-btn-send {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 8px 20px; border: none; background: var(--tnb-accent);
    color: var(--tnb-white); font-size: 13px; font-weight: 600;
    border-radius: var(--tnb-radius); cursor: pointer;
    transition: var(--tnb-transition); font-family: var(--tnb-font);
    box-shadow: 0 1px 3px rgba(37,99,235,0.25);
}

.tnb-btn-send:hover {
    background: var(--tnb-accent-hover);
    box-shadow: 0 4px 12px rgba(37,99,235,0.3);
    transform: translateY(-1px);
}

.tnb-btn-send:disabled { opacity: 0.5; cursor: not-allowed; transform: none; box-shadow: none; }

/* === RIGHT SIDEBAR === */
.tnb-sidebar-right {
    width: var(--tnb-info-width); min-width: var(--tnb-info-width);
    border-left: 1px solid var(--tnb-border); background: var(--tnb-white);
    overflow-y: auto; transition: var(--tnb-transition);
}

.tnb-sidebar-right::-webkit-scrollbar { width: 4px; }
.tnb-sidebar-right::-webkit-scrollbar-thumb { background: var(--tnb-border); border-radius: 4px; }

.tnb-info-panel { padding: 0; }
.tnb-info-header {
    display: flex; align-items: center; justify-content: space-between;
    padding: 16px 20px; border-bottom: 1px solid var(--tnb-border-light);
}
.tnb-info-title { font-size: 15px; font-weight: 700; color: var(--tnb-text-primary); margin: 0; }

.tnb-info-section { padding: 16px 20px; border-bottom: 1px solid var(--tnb-border-light); }

.tnb-info-section-header {
    display: flex; align-items: center; justify-content: space-between;
    margin-bottom: 12px;
}

.tnb-info-section-title {
    font-size: 11.5px; font-weight: 700; color: var(--tnb-text-secondary);
    text-transform: uppercase; letter-spacing: 0.8px; margin: 0;
    display: flex; align-items: center; gap: 6px;
}

.tnb-count-badge {
    background: var(--tnb-accent-light); color: var(--tnb-accent);
    font-size: 10px; font-weight: 700; padding: 1px 7px;
    border-radius: 10px; line-height: 18px;
}

.tnb-btn-add-participant {
    width: 28px; height: 28px; border: none;
    background: var(--tnb-accent-light); color: var(--tnb-accent);
    cursor: pointer; border-radius: 6px;
    display: flex; align-items: center; justify-content: center;
    transition: var(--tnb-transition-fast);
}
.tnb-btn-add-participant:hover { background: var(--tnb-accent); color: var(--tnb-white); }

/* Participants list */
.tnb-participant-item {
    display: flex; align-items: center; justify-content: space-between;
    padding: 8px 0; border-bottom: 1px solid var(--tnb-border-light);
}
.tnb-participant-item:last-child { border-bottom: none; }

.tnb-participant-info { display: flex; align-items: center; gap: 10px; flex: 1; min-width: 0; }
.tnb-participant-details { display: flex; flex-direction: column; min-width: 0; }
.tnb-participant-name { font-size: 13px; font-weight: 500; color: var(--tnb-text-primary); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.tnb-participant-role { font-size: 11px; color: var(--tnb-text-muted); }

.tnb-btn-remove-participant {
    width: 24px; height: 24px; border: none; background: transparent;
    color: var(--tnb-text-muted); cursor: pointer; border-radius: 4px;
    display: flex; align-items: center; justify-content: center;
    opacity: 0; transition: var(--tnb-transition-fast);
}
.tnb-participant-item:hover .tnb-btn-remove-participant { opacity: 1; }
.tnb-btn-remove-participant:hover { background: var(--tnb-danger-light); color: var(--tnb-danger); }

/* Read status */
.tnb-read-item { display: flex; align-items: center; gap: 10px; padding: 6px 0; }
.tnb-read-details { display: flex; flex-direction: column; }
.tnb-read-name { font-size: 12.5px; font-weight: 500; color: var(--tnb-text-primary); }
.tnb-read-time { font-size: 11px; display: flex; align-items: center; gap: 4px; }

/* Settings */
.tnb-settings-row { margin-bottom: 10px; }
.tnb-settings-row label { font-size: 12px; color: var(--tnb-text-secondary); margin-bottom: 5px; display: block; font-weight: 500; }
.tnb-label-change-select {
    width: 100%; padding: 6px 10px;
    border: 1.5px solid var(--tnb-border); border-radius: 6px;
    font-size: 12.5px; outline: none; font-family: var(--tnb-font);
}

/* Add participant form */
.tnb-add-participant-form {
    margin-bottom: 12px; padding: 12px;
    background: var(--tnb-bg); border-radius: var(--tnb-radius);
    border: 1px solid var(--tnb-border-light);
}

.tnb-user-select {
    width: 100%; padding: 8px 10px;
    border: 1.5px solid var(--tnb-border); border-radius: 6px;
    font-size: 13px; font-family: var(--tnb-font);
}

.tnb-add-participant-actions { display: flex; gap: 6px; }

/* === BUTTONS === */
.tnb-btn-primary {
    display: inline-flex; align-items: center; gap: 7px;
    padding: 9px 20px; border: none; background: var(--tnb-accent);
    color: var(--tnb-white); font-size: 13.5px; font-weight: 600;
    border-radius: var(--tnb-radius); cursor: pointer;
    transition: var(--tnb-transition); font-family: var(--tnb-font);
    box-shadow: 0 1px 3px rgba(37,99,235,0.25);
}
.tnb-btn-primary:hover {
    background: var(--tnb-accent-hover);
    box-shadow: 0 4px 12px rgba(37,99,235,0.3);
    transform: translateY(-1px);
}

.tnb-btn-light {
    display: inline-flex; align-items: center; gap: 7px;
    padding: 9px 20px; border: 1.5px solid var(--tnb-border);
    background: var(--tnb-white); color: var(--tnb-text-secondary);
    font-size: 13.5px; font-weight: 500; border-radius: var(--tnb-radius);
    cursor: pointer; transition: var(--tnb-transition); font-family: var(--tnb-font);
}
.tnb-btn-light:hover { background: var(--tnb-bg); color: var(--tnb-text-primary); border-color: var(--tnb-text-muted); }

.tnb-btn-sm { padding: 5px 14px; font-size: 12px; }

/* === COMPOSE MODAL === */
.tnb-compose-dialog { max-width: 980px; }
.tnb-compose-dialog .modal-content {
    border: 0; border-radius: 20px; overflow: hidden;
    box-shadow: 0 30px 80px rgba(15, 23, 42, 0.24);
}

.tnb-modal-header {
    border-bottom: 1px solid var(--tnb-border-light);
    padding: 18px 24px;
    background: linear-gradient(135deg, #f8fbff 0%, #ffffff 65%, #eef4ff 100%);
}

.tnb-modal-header .modal-title {
    font-size: 17px; font-weight: 700; color: var(--tnb-text-primary);
    display: flex; align-items: center; gap: 10px; letter-spacing: -0.2px;
}

.tnb-modal-subtitle {
    margin-top: 4px; font-size: 12.5px; color: var(--tnb-text-muted);
}

.tnb-modal-body {
    padding: 24px; background: linear-gradient(180deg, #fafcff 0%, #f8fafc 100%);
    max-height: 75vh; overflow-y: auto;
}

.tnb-compose-panel {
    background: #fff;
    border: 1px solid var(--tnb-border-light);
    border-radius: 18px;
    padding: 18px;
    box-shadow: 0 10px 30px rgba(15, 23, 42, 0.05);
}

.tnb-modal-footer {
    padding: 14px 24px; border-top: 1px solid var(--tnb-border-light);
    background: var(--tnb-bg); display: flex; justify-content: flex-end; gap: 10px;
}

/* === QUICK GROUP CHIPS === */
.tnb-section-head {
    display: flex; align-items: flex-end; justify-content: space-between;
    gap: 12px; margin-bottom: 8px;
}

.tnb-section-note,
.tnb-recipient-hint {
    font-size: 11.5px; color: var(--tnb-text-muted);
}

.tnb-quick-groups {
    display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 12px;
}

.tnb-group-chip {
    display: inline-flex; align-items: center; gap: 8px;
    padding: 7px 12px; border: 1px solid #dbe5f2;
    background: #fff; color: #334155;
    font-size: 12.5px; font-weight: 600; border-radius: 999px;
    cursor: pointer; transition: var(--tnb-transition-fast);
    font-family: var(--tnb-font); white-space: nowrap;
    box-shadow: 0 1px 2px rgba(15, 23, 42, 0.05);
}

.tnb-chip-icon {
    width: 22px; height: 22px; border-radius: 50%;
    display: inline-flex; align-items: center; justify-content: center;
    background: #eff6ff; color: var(--tnb-accent);
}

.tnb-chip-text {
    max-width: 200px; overflow: hidden; text-overflow: ellipsis;
}

.tnb-group-chip:hover {
    border-color: var(--tnb-accent); color: var(--tnb-accent);
    background: var(--tnb-accent-light); transform: translateY(-1px);
}

.tnb-group-chip.active {
    border-color: var(--tnb-accent); background: var(--tnb-accent);
    color: var(--tnb-white); box-shadow: 0 8px 20px rgba(37, 99, 235, 0.22);
}

.tnb-group-chip.active .tnb-chip-icon {
    background: rgba(255,255,255,0.16); color: #fff;
}

.tnb-group-count {
    font-size: 10px; background: rgba(15,23,42,0.08);
    padding: 0 6px; border-radius: 999px; line-height: 18px; font-weight: 700;
}

.tnb-group-chip.active .tnb-group-count { background: rgba(255,255,255,0.22); }

/* === FORM ELEMENTS === */
.tnb-form-group { margin-bottom: 18px; }

.tnb-form-row { display: flex; gap: 16px; }
.tnb-form-group-flex { flex: 1; min-width: 0; }
.tnb-form-group-label { width: 220px; flex-shrink: 0; }

.tnb-form-label {
    display: block; font-size: 13px; font-weight: 700;
    color: var(--tnb-text-primary); margin-bottom: 7px;
}

.tnb-form-input,
.tnb-form-select,
.tnb-modal-body textarea.tnb-summernote-editor {
    width: 100%; padding: 10px 14px;
    border: 1.5px solid var(--tnb-border); border-radius: 12px;
    font-size: 14px; color: var(--tnb-text-primary);
    background: var(--tnb-white); outline: none;
    transition: var(--tnb-transition); font-family: var(--tnb-font);
}

.tnb-modal-body textarea.tnb-summernote-editor {
    min-height: 240px; resize: vertical;
}

.tnb-form-input:focus, .tnb-form-select:focus, .tnb-modal-body textarea.tnb-summernote-editor:focus {
    border-color: var(--tnb-accent);
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

/* Summernote in compose modal */
.tnb-modal-body .note-editor {
    border: 1.5px solid var(--tnb-border) !important;
    border-radius: 14px !important;
    overflow: hidden;
    background: #fff;
    box-shadow: 0 2px 4px rgba(15, 23, 42, 0.03);
}

.tnb-modal-body .note-editor.note-frame:focus-within {
    border-color: var(--tnb-accent) !important;
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1) !important;
}

.tnb-modal-body .note-toolbar {
    background: #f8fafc !important;
    border-bottom: 1px solid var(--tnb-border-light) !important;
    padding: 8px 10px !important;
}

.tnb-modal-body .note-toolbar .note-btn {
    border-radius: 8px !important;
}

.tnb-modal-body .note-editable {
    min-height: 220px !important; padding: 14px 16px !important;
    font-size: 14px !important; line-height: 1.7 !important;
    color: var(--tnb-text-primary) !important;
    font-family: var(--tnb-font) !important;
}

.tnb-modal-body .note-statusbar { display: none !important; }

/* Select2 Override */
.tnb-modal-body .select2-container { width: 100% !important; }

.tnb-modal-body .select2-container .select2-selection--multiple {
    border: 1.5px solid var(--tnb-border) !important;
    border-radius: 12px !important;
    min-height: 46px; background: var(--tnb-white);
    padding: 6px 8px !important;
}

.tnb-modal-body .select2-container--focus .select2-selection--multiple {
    border-color: var(--tnb-accent) !important;
    box-shadow: 0 0 0 3px rgba(37,99,235,0.1) !important;
}

.tnb-modal-body .select2-container .select2-selection--multiple .select2-selection__choice {
    background: var(--tnb-accent-light) !important;
    border: 1px solid var(--tnb-accent-soft) !important;
    border-radius: 999px !important; padding: 4px 9px !important;
    font-size: 12.5px !important; color: var(--tnb-accent) !important;
    font-weight: 600 !important;
}

/* File Upload */
.tnb-file-upload-area {
    position: relative; border: 2px dashed #cdd9ea;
    border-radius: 16px; padding: 24px;
    text-align: center; transition: var(--tnb-transition);
    cursor: pointer; background: linear-gradient(180deg, #fbfdff 0%, #f8fbff 100%);
}

.tnb-file-upload-area:hover {
    border-color: var(--tnb-accent);
    background: var(--tnb-accent-light);
}

.tnb-file-input {
    position: absolute; top: 0; left: 0;
    width: 100%; height: 100%; opacity: 0; cursor: pointer;
}

.tnb-file-upload-label {
    display: flex; flex-direction: column; align-items: center;
    gap: 6px; color: var(--tnb-text-muted); font-size: 13px;
}

.tnb-upload-title {
    font-weight: 600; color: var(--tnb-text-secondary);
}

.tnb-upload-caption {
    color: var(--tnb-text-muted); font-size: 11.5px;
}

.tnb-file-list { margin-top: 10px; display: flex; flex-wrap: wrap; gap: 6px; }
.tnb-file-chip {
    display: inline-flex; align-items: center; gap: 6px;
    padding: 6px 10px; border-radius: 999px;
    background: #fff; border: 1px solid var(--tnb-border-light);
    color: var(--tnb-text-secondary); font-size: 12px; font-weight: 500;
}

/* Loading */
.tnb-loading { display: flex; align-items: center; justify-content: center; padding: 50px 0; }

/* === RESPONSIVE === */
@media (max-width: 1400px) {
    :root { --tnb-sidebar-width: 340px; --tnb-info-width: 280px; }
}

@media (max-width: 1200px) {
    :root { --tnb-sidebar-width: 320px; --tnb-info-width: 280px; }
    .tnb-sidebar-right {
        position: fixed; right: 0; top: 60px;
        height: calc(100vh - 60px); z-index: 1050;
        box-shadow: var(--tnb-shadow-lg);
        transform: translateX(100%);
        transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    }
    .tnb-sidebar-right.tnb-sidebar-open { transform: translateX(0); }
    .tnb-sidebar-overlay {
        display: none; position: fixed; top: 60px; left: 0; right: 0; bottom: 0;
        background: rgba(0,0,0,0.3); z-index: 1040;
    }
    .tnb-sidebar-overlay.active { display: block; }
    .tnb-form-row { flex-direction: column; gap: 0; }
    .tnb-form-group-label { width: 100%; }
}

@media (max-width: 992px) {
    :root { --tnb-sidebar-width: 300px; }
    .tnb-detail-header { padding: 14px 16px; }
    .tnb-messages-area { padding: 16px; }
    .tnb-reply-box { padding: 12px 16px; }
    .tnb-detail-subject { font-size: 17px; }
}

@media (max-width: 768px) {
    .tnb-container {
        flex-direction: column;
        height: calc(100vh - 60px);
        min-height: calc(100vh - 60px);
    }

    .tnb-sidebar-left {
        width: 100% !important; min-width: 100% !important;
        max-height: 45vh; border-right: none;
        border-bottom: 2px solid var(--tnb-border);
    }

    .tnb-container.tnb-thread-active .tnb-sidebar-left { display: none; }
    .tnb-container.tnb-thread-active .tnb-main-content { min-height: calc(100vh - 60px); }

    .tnb-mobile-back {
        display: inline-flex !important;
        align-items: center; gap: 4px; padding: 6px 12px;
        border: none; background: var(--tnb-bg);
        color: var(--tnb-text-secondary); border-radius: 6px;
        cursor: pointer; font-size: 12px; font-weight: 500; margin-right: 8px;
    }

    .tnb-main-content { min-height: 0; flex: 1; }

    .tnb-sidebar-right {
        width: 100% !important; min-width: 100% !important;
        position: fixed; left: 0; right: 0; top: 60px;
        height: calc(100vh - 60px); z-index: 1050;
        border-left: none; border-top: 1px solid var(--tnb-border);
        transform: translateX(100%);
    }
    .tnb-sidebar-right.tnb-sidebar-open { transform: translateX(0); }

    .tnb-detail-subject { font-size: 16px; }
    .tnb-reply-box { padding: 10px 12px; }
    .tnb-reply-editor-container { gap: 8px; }
    .tnb-reply-avatar { display: none; }

    .tnb-modal-body { padding: 16px; }
    .tnb-modal-header { padding: 14px 16px; }
    .tnb-modal-footer { padding: 10px 16px; }

    .tnb-quick-groups { gap: 4px; }
    .tnb-group-chip { padding: 4px 10px; font-size: 11px; }
}

.tnb-mobile-back { display: none; }

@media (max-width: 480px) {
    .tnb-sidebar-header { padding: 14px 14px 10px; }
    .tnb-detail-header { padding: 12px; }
    .tnb-messages-area { padding: 12px; }
    .tnb-detail-actions { gap: 0; }
    .tnb-action-btn { width: 30px; height: 30px; }
}

/* === SELECT2 SIDEBAR === */
.tnb-add-participant-form .select2-container { width: 100% !important; }
.tnb-add-participant-form .select2-container .select2-selection--single {
    border: 1.5px solid var(--tnb-border); border-radius: 6px; height: 34px;
}

/* === HIDDEN UTILITIES === */
.tnb-compose-editor { display: none; }