:root{--alive-green:#25d366;--alive-dark:#111;--alive-bubble:#e7fbe9}
body{background:#f7f7f9}
.navbar-dark .navbar-brand{font-weight:700}
.chat-card{min-height:70vh}
#contactsList{max-height:calc(100vh - 220px)}
#messages{max-height:calc(100vh - 280px)}
.message{display:flex;margin-bottom:.5rem}
.message.me{justify-content:flex-end}
.bubble{max-width:70%;padding:.5rem .75rem;border-radius:1rem}
.message.me .bubble{background:var(--alive-green);color:#fff;border-bottom-right-radius:.2rem}
.message.them .bubble{background:#fff;border:1px solid #eee;border-bottom-left-radius:.2rem}
.msg-time{font-size:.75rem;opacity:.7;margin-top:.25rem}
.list-item{padding:.75rem 1rem;border-bottom:1px solid #eee;cursor:pointer}
.list-item:hover{background:#f5f5f5}
.avatar{font-size:1rem}
.card-header{background:#fff}
.btn-success{background:var(--alive-green);border-color:var(--alive-green)}
@media (max-width: 767.98px){
 .chat-card{min-height:80vh}
 #contactsList{max-height:calc(100vh - 280px)}
 #messages{max-height:calc(100vh - 240px)}
}