.itfv3-shell {
    display: grid;
    grid-template-columns: 280px 1fr;
    min-height: 640px;
    border: 1px solid #dcdcde;
    background: #ffffff;
    color: #1d2327;
}

.itfv3-shell__sidebar {
    display: flex;
    flex-direction: column;
    gap: 16px;
    padding: 20px;
    border-right: 1px solid #dcdcde;
    background: #f6f7f7;
}

.itfv3-shell__brand {
    font-size: 18px;
    font-weight: 700;
    line-height: 1.3;
}

.itfv3-shell__new-chat {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 100%;
    min-height: 44px;
    padding: 10px 14px;
    border: 1px solid #2271b1;
    background: #2271b1;
    color: #ffffff;
    cursor: pointer;
    border-radius: 6px;
    font-size: 16px;
    font-weight: 600;
}

.itfv3-shell__new-chat:hover {
    background: #135e96;
    border-color: #135e96;
}

.itfv3-shell__new-chat:disabled {
    opacity: 0.7;
    cursor: not-allowed;
}

.itfv3-shell__history {
    flex: 1;
    padding: 12px;
    border: 1px solid #dcdcde;
    background: #ffffff;
    overflow: auto;
    min-height: 200px;
}

.itfv3-history-list {
    list-style: none;
    margin: 0;
    padding: 0;
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.itfv3-history-list__item {
    margin: 0;
    padding: 0;
}

.itfv3-history-list__button {
    display: block;
    width: 100%;
    padding: 12px 14px;
    border: 1px solid #dcdcde;
    border-radius: 6px;
    background: #f6f7f7;
    color: #1d2327;
    text-align: left;
    font-size: 15px;
    line-height: 1.4;
    cursor: pointer;
    word-break: break-word;
}

.itfv3-history-list__button:hover {
    background: #eef4fb;
    border-color: #2271b1;
}

.itfv3-shell__main {
    display: grid;
    grid-template-rows: auto 1fr auto;
    min-width: 0;
}

.itfv3-shell__topbar {
    padding: 20px;
    border-bottom: 1px solid #dcdcde;
    background: #ffffff;
}

.itfv3-shell__title {
    margin: 0;
    font-size: 20px;
    line-height: 1.3;
}

.itfv3-shell__messages {
    padding: 20px;
    background: #ffffff;
    overflow: auto;
}

.itfv3-shell__empty {
    display: flex;
    align-items: center;
    justify-content: center;
    min-height: 320px;
    border: 1px dashed #c3c4c7;
    background: #f6f7f7;
    text-align: center;
    padding: 20px;
}

.itfv3-shell__composer {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 12px;
    padding: 20px;
    border-top: 1px solid #dcdcde;
    background: #ffffff;
}

.itfv3-shell__textarea {
    width: 100%;
    min-height: 96px;
    resize: vertical;
    padding: 12px;
    border: 1px solid #8c8f94;
    border-radius: 6px;
    background: #ffffff;
    color: #1d2327;
}

.itfv3-shell__send {
    min-width: 120px;
    min-height: 44px;
    padding: 10px 16px;
    border: 1px solid #2271b1;
    border-radius: 6px;
    background: #2271b1;
    color: #ffffff;
    cursor: pointer;
    font-size: 16px;
    font-weight: 600;
}

.itfv3-shell__send[disabled],
.itfv3-shell__textarea[disabled] {
    opacity: 0.7;
    cursor: not-allowed;
}

.itfv3-shell--guest,
.itfv3-shell--loading {
    padding: 16px;
    border: 1px solid #dcdcde;
    background: #ffffff;
}

@media (max-width: 900px) {
    .itfv3-shell {
        grid-template-columns: 1fr;
    }

    .itfv3-shell__sidebar {
        border-right: 0;
        border-bottom: 1px solid #dcdcde;
    }

    .itfv3-shell__composer {
        grid-template-columns: 1fr;
    }

    .itfv3-shell__send {
        width: 100%;
    }
}