.dhcb-floating-btn {
    position: fixed;
    right: 24px;
    bottom: 24px;
    width: 56px;
    height: 56px;
    border-radius: 50%;
    background: #2d2d2d;
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    box-shadow: 0 10px 20px rgba(0,0,0,.25);
    z-index: 9999;
    font-weight: 600;
    user-select: none;
}
.dhcb-panel {
    position: fixed;
    right: 24px;
    bottom: 96px;
    width: min(420px, calc(100% - 48px));
    max-height: 70vh;
    display: none;
    flex-direction: column;
    border-radius: 12px;
    overflow: hidden;
    background: #111;
    color: #f1f1f1;
    border: 1px solid rgba(255,255,255,.08);
    box-shadow: 0 10px 30px rgba(0,0,0,.35);
    z-index: 9999;
}
.dhcb-panel.open { display: flex; }
.dhcb-header {
    padding: 12px 16px;
    background: #1f1f1f;
    font-weight: 700;
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.dhcb-body {
    padding: 12px;
    overflow-y: auto;
    gap: 8px;
    display: flex;
    flex-direction: column;
}
.dhcb-msg {
    padding: 8px 10px;
    border-radius: 8px;
    line-height: 1.4;
    white-space: pre-wrap;
}
.dhcb-msg.user {
    background: #243b55;
    align-self: flex-end;
}
.dhcb-msg.assistant {
    background: #222;
    border: 1px solid rgba(255,255,255,.06);
    align-self: flex-start;
}
.dhcb-footer {
    display: flex;
    gap: 8px;
    padding: 12px;
    background: #1b1b1b;
    border-top: 1px solid rgba(255,255,255,.08);
}
.dhcb-input {
    flex: 1;
    padding: 10px 12px;
    border-radius: 8px;
    border: 1px solid rgba(255,255,255,.12);
    background: #0e0e0e;
    color: #fff;
    outline: none;
}
.dhcb-send {
    padding: 10px 14px;
    border-radius: 8px;
    border: none;
    background: #3b82f6;
    color: #fff;
    font-weight: 700;
    cursor: pointer;
}
.dhcb-close {
    cursor: pointer;
    opacity: .8;
}