#btc-bubble {
    position: fixed;
    bottom: 28px;
    right: 28px;
    width: 62px;
    height: 62px;
    background: #185FA5;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    z-index: 99999;
    box-shadow: 0 4px 16px rgba(24,95,165,0.4);
    transition: transform 0.2s, box-shadow 0.2s;
}

#btc-bubble:hover {
    transform: scale(1.08);
    box-shadow: 0 6px 20px rgba(24,95,165,0.5);
}

#btc-bubble i {
    font-size: 26px;
    color: #fff;
}

#btc-window {
    position: fixed;
    bottom: 104px;
    right: 28px;
    width: 350px;
    height: 500px;
    background: #fff;
    border-radius: 16px;
    border: 0.5px solid rgba(0,0,0,0.12);
    box-shadow: 0 8px 32px rgba(24,95,165,0.15);
    display: none;
    flex-direction: column;
    z-index: 99998;
    overflow: hidden;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    transition: opacity 0.2s, transform 0.2s;
}

#btc-window.open {
    display: flex;
}

#btc-header {
    background: #185FA5;
    padding: 14px 16px;
    display: flex;
    align-items: center;
    gap: 10px;
}

#btc-header-avatar {
    width: 38px;
    height: 38px;
    background: #E6F1FB;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

#btc-header-avatar i {
    font-size: 18px;
    color: #185FA5;
}

#btc-header-info { flex: 1; }

#btc-header-name {
    font-size: 14px;
    font-weight: 500;
    color: #fff;
    margin: 0;
}

#btc-header-status {
    font-size: 11px;
    color: #B5D4F4;
    margin: 0;
    display: flex;
    align-items: center;
    gap: 4px;
}

.btc-dot {
    width: 6px;
    height: 6px;
    background: #5DCAA5;
    border-radius: 50%;
}

#btc-header button {
    background: none;
    border: none;
    color: #B5D4F4;
    font-size: 20px;
    cursor: pointer;
    padding: 0;
    line-height: 1;
}

#btc-messages {
    flex: 1;
    overflow-y: auto;
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 10px;
    background: #F4F8FD;
}

#btc-messages::-webkit-scrollbar { width: 4px; }
#btc-messages::-webkit-scrollbar-track { background: transparent; }
#btc-messages::-webkit-scrollbar-thumb { background: #B5D4F4; border-radius: 4px; }

.btc-bot-msg, .btc-user-msg, .btc-typing-msg {
    max-width: 82%;
    padding: 10px 14px;
    border-radius: 14px;
    font-size: 13.5px;
    line-height: 1.55;
}

.btc-bot-msg {
    background: #fff;
    color: #1a1a2e;
    border: 0.5px solid rgba(24,95,165,0.15);
    border-bottom-left-radius: 4px;
    align-self: flex-start;
}

.btc-user-msg {
    background: #185FA5;
    color: #fff;
    border-bottom-right-radius: 4px;
    align-self: flex-end;
}

.btc-typing-msg {
    background: #fff;
    border: 0.5px solid rgba(24,95,165,0.15);
    border-bottom-left-radius: 4px;
    align-self: flex-start;
    padding: 12px 16px;
}

.btc-dots {
    display: flex;
    gap: 5px;
    align-items: center;
}

.btc-dots span {
    width: 7px;
    height: 7px;
    background: #185FA5;
    border-radius: 50%;
    animation: btcBounce 1.2s infinite;
}

.btc-dots span:nth-child(2) { animation-delay: 0.2s; }
.btc-dots span:nth-child(3) { animation-delay: 0.4s; }

@keyframes btcBounce {
    0%, 60%, 100% { transform: translateY(0); }
    30% { transform: translateY(-6px); }
}

#btc-footer {
    display: flex;
    padding: 12px;
    gap: 8px;
    align-items: center;
    border-top: 0.5px solid rgba(24,95,165,0.12);
    background: #fff;
}

#btc-input {
    flex: 1;
    padding: 10px 14px;
    border: 0.5px solid rgba(24,95,165,0.25);
    border-radius: 24px;
    font-size: 13px;
    outline: none;
    background: #F4F8FD;
    color: #1a1a2e;
    transition: border-color 0.2s;
}

#btc-input:focus {
    border-color: #185FA5;
    background: #fff;
}

#btc-send-btn {
    width: 40px;
    height: 40px;
    background: #185FA5;
    border: none;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    cursor: pointer;
    transition: background 0.2s, transform 0.1s;
    flex-shrink: 0;
}

#btc-send-btn:hover { background: #0C447C; }
#btc-send-btn:active { transform: scale(0.95); }

#btc-send-btn i {
    font-size: 16px;
    color: #fff;
}

#btc-branding {
    text-align: center;
    font-size: 10px;
    color: #aaa;
    padding: 5px 0 4px;
    background: #fff;
}

@media (max-width: 400px) {
    #btc-window {
        width: calc(100vw - 24px);
        right: 12px;
        bottom: 96px;
    }
    #btc-bubble { right: 16px; bottom: 20px; }
}