.usb-support {
  position: fixed;
  right: 1.1rem;
  bottom: 1.1rem;
  z-index: 80;
  font-family: Inter, "Segoe UI", system-ui, sans-serif;
}

.usb-support-toggle {
  display: inline-flex;
  align-items: center;
  gap: 0.55rem;
  border: 0;
  border-radius: 999px;
  padding: 0.7rem 1.05rem;
  color: #fff;
  font-weight: 700;
  letter-spacing: 0.04em;
  cursor: pointer;
  background: linear-gradient(90deg, #7a3dff 0%, #3d8bff 100%);
  box-shadow: 0 10px 28px rgba(90, 60, 255, 0.35);
}

.usb-support-toggle:hover { filter: brightness(1.08); }

.usb-support-badge {
  min-width: 1.15rem;
  height: 1.15rem;
  padding: 0 0.3rem;
  border-radius: 999px;
  background: #ff6b6b;
  color: #fff;
  font-size: 0.72rem;
  line-height: 1.15rem;
  text-align: center;
}

.usb-support-panel {
  display: none;
  width: min(380px, calc(100vw - 1.6rem));
  height: min(520px, calc(100vh - 6rem));
  margin-bottom: 0.7rem;
  flex-direction: column;
  overflow: hidden;
  background: rgba(12, 14, 24, 0.96);
  border: 1px solid rgba(155, 124, 255, 0.28);
  border-radius: 16px;
  box-shadow: 0 18px 50px rgba(0, 0, 0, 0.45);
  color: #f4f7ff;
}

.usb-support.is-open .usb-support-panel { display: flex; }

.usb-support-head {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 0.75rem;
  padding: 0.9rem 1rem 0.75rem;
  border-bottom: 1px solid rgba(255, 255, 255, 0.06);
}

.usb-support-head strong { display: block; font-size: 0.98rem; }
.usb-support-head span { color: #8b93a7; font-size: 0.78rem; }

.usb-support-close {
  background: none;
  border: 0;
  color: #9aa3b8;
  font-size: 1.2rem;
  cursor: pointer;
  line-height: 1;
}

.usb-support-body {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.usb-support-inbox {
  overflow-y: auto;
  padding: 0.45rem;
}

.usb-support-item {
  width: 100%;
  text-align: left;
  border: 0;
  background: rgba(255, 255, 255, 0.03);
  color: inherit;
  border-radius: 10px;
  padding: 0.7rem 0.75rem;
  margin-bottom: 0.4rem;
  cursor: pointer;
}

.usb-support-item:hover,
.usb-support-item.is-on { background: rgba(122, 61, 255, 0.16); }

.usb-support-item b { display: block; font-size: 0.88rem; }
.usb-support-item em {
  display: block;
  font-style: normal;
  color: #8b93a7;
  font-size: 0.75rem;
  margin-top: 0.15rem;
}

.usb-support-thread {
  flex: 1;
  min-height: 0;
  display: flex;
  flex-direction: column;
}

.usb-support-log {
  flex: 1;
  overflow-y: auto;
  padding: 0.85rem 0.9rem;
  display: flex;
  flex-direction: column;
  gap: 0.55rem;
}

.usb-support-msg {
  max-width: 85%;
  padding: 0.55rem 0.7rem;
  border-radius: 12px;
  font-size: 0.9rem;
  line-height: 1.4;
}

.usb-support-msg small {
  display: block;
  font-size: 0.68rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: 0.2rem;
  opacity: 0.75;
}

.usb-support-msg.is-me {
  align-self: flex-end;
  background: linear-gradient(90deg, rgba(122, 61, 255, 0.35), rgba(61, 139, 255, 0.28));
}

.usb-support-msg.is-them {
  align-self: flex-start;
  background: rgba(255, 255, 255, 0.06);
}

.usb-support-form {
  display: flex;
  gap: 0.45rem;
  padding: 0.7rem;
  border-top: 1px solid rgba(255, 255, 255, 0.06);
}

.usb-support-form input {
  flex: 1;
  border: 1px solid rgba(255, 255, 255, 0.12);
  background: #0c0e16;
  color: #f4f7ff;
  border-radius: 10px;
  padding: 0.55rem 0.7rem;
  font: inherit;
}

.usb-support-form button {
  border: 0;
  border-radius: 10px;
  padding: 0.55rem 0.8rem;
  font-weight: 700;
  color: #fff;
  cursor: pointer;
  background: linear-gradient(90deg, #7a3dff 0%, #3d8bff 100%);
}

.usb-support-back {
  border: 0;
  background: none;
  color: #3ecbff;
  font-size: 0.78rem;
  font-weight: 600;
  cursor: pointer;
  padding: 0.45rem 0.9rem 0;
  text-align: left;
}

.usb-support-empty {
  color: #8b93a7;
  font-size: 0.88rem;
  padding: 1rem;
}