:root{
  --bg: #f6f7fb;
  --card: rgba(255,255,255,.86);
  --card-solid: #ffffff;
  --stroke: rgba(17,24,39,.10);
  --stroke-strong: rgba(17,24,39,.18);
  --text: #0f172a;
  --muted: rgba(15,23,42,.70);

  --brand: #2b6cff;
  --brand2: #8a5cff;

  --shadow: 0 14px 40px rgba(17,24,39,.10);
  --shadow-sm: 0 8px 24px rgba(17,24,39,.08);

  --radius: 18px;
  --radius-sm: 14px;

  --composer-h: 64px; /* JS sẽ cập nhật */
  --kbd-offset: 0px;
}

html, body{ height:100%; }

body{
  margin:0;
  color: var(--text);
  font-family: system-ui, -apple-system, Segoe UI, Roboto, Arial, sans-serif;
  background:
    radial-gradient(1200px 800px at 20% -10%, rgba(43,108,255,.20), transparent 60%),
    radial-gradient(900px 700px at 110% 10%, rgba(138,92,255,.16), transparent 55%),
    var(--bg);
  padding-bottom: calc(var(--composer-h) + env(safe-area-inset-bottom, 0px));
}

.wrap{
  max-width: 980px;
  margin: 0 auto;
  padding: 14px;
  min-height: 100dvh;
  display:flex;
  flex-direction:column;
  gap: 12px;
}

/* ===== topbar ===== */
.topbar{
  position: sticky;
  top: 10px;
  z-index: 40;
  display:flex;
  align-items:center;
  justify-content: space-between;
  gap: 12px;
  padding: 12px 14px;
  border-radius: var(--radius);
  background: var(--card);
  border: 1px solid var(--stroke);
  box-shadow: var(--shadow-sm);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.topbar__left{ display:flex; align-items:center; gap: 12px; min-width: 0; }
.topbar__avatar{
  width: 40px; height: 40px;
  border-radius: 999px;
  display:grid; place-items:center;
  font-weight: 800;
  color:#fff;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
  box-shadow: 0 10px 26px rgba(43,108,255,.20);
  flex: 0 0 auto;
}
.topbar__title{ font-weight: 800; letter-spacing: .2px; line-height: 1.1; }
.topbar__sub{ font-size: 12px; color: var(--muted); display:flex; align-items:center; gap: 8px; }
.dot{ width:8px; height:8px; border-radius:999px; background:#22c55e; box-shadow:0 0 0 4px rgba(34,197,94,.16); }

.topbar__actions{ display:inline-flex; gap: 10px; align-items:center; }
.clear-top{
  display:inline-flex;
  align-items:center;
  gap: 8px;
  padding: 9px 12px;
  border-radius: 999px;
  border: 1px solid var(--stroke-strong);
  background: rgba(255,255,255,.9);
  color: var(--text);
  cursor:pointer;
  font-size: 13px;
  line-height: 1;
}
.clear-top .ico{ width: 16px; height: 16px; fill: currentColor; opacity: .85; }
.clear-top:active{ transform: translateY(1px); }

.scroll-bottom{
  width: 40px;
  height: 40px;
  border-radius: 999px;
  border: 1px solid var(--stroke);
  background: rgba(255,255,255,.85);
  color: var(--text);
  display:grid;
  place-items:center;
  box-shadow: 0 10px 26px rgba(17,24,39,.08);
  opacity: 0;
  pointer-events: none;
  transition: opacity .18s ease;
}
.scroll-bottom.show{ opacity: 1; pointer-events: auto; }
.scroll-bottom svg{ width: 20px; height: 20px; }

/* ===== chat ===== */
.chat{
  flex: 1;
  min-height: 0;
  overflow:auto;
  padding: 14px;
  border-radius: var(--radius);
  background: rgba(255,255,255,.80);
  border: 1px solid var(--stroke);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  padding-bottom: calc(14px + var(--composer-h) + var(--kbd-offset) + env(safe-area-inset-bottom, 0px));
}

.msgrow{ display:flex; margin: 10px 0; }
.msgrow.me{ justify-content:flex-end; }
.msgrow.bot{ justify-content:flex-start; }

.bubble{
  position: relative;
  max-width: 100%;
  border-radius: var(--radius);
  padding: 12px 12px;
  line-height: 1.45;
  font-size: 14px;
  overflow-wrap: anywhere;
  word-break: break-word;
}

.me .bubble{
  max-width: 70%;
  color:#fff;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
  border-bottom-right-radius: 8px;
  box-shadow: 0 16px 36px rgba(43,108,255,.18);
}

.bot .bubble{
background: rgba(240,242,247,.92);
border: 1px solid rgba(17,24,39,.06);
color: var(--text);
border-bottom-left-radius: 8px;
padding: 14px 16px;
padding-right: 44px;
max-width: 100%;
}

/* copy button */
.copy-btn{
  position:absolute;
  top: 10px;
  right: 10px;
  width: 28px;
  height: 28px;
  border-radius: 10px;
  border: 1px solid rgba(17,24,39,.10);
  background: rgba(255,255,255,.75);
  color: rgba(15,23,42,.78);
  display:grid;
  place-items:center;
  cursor:pointer;
  padding: 0;
  transition: transform .12s ease, opacity .12s ease;
}
.copy-btn:hover{ transform: translateY(-1px); }
.copy-btn:active{ transform: translateY(0); opacity: .8; }
.copy-btn svg{ width: 16px; height: 16px; }

/* code blocks */
pre{ margin: 10px 0 0; }
pre code{
  display:block;
  padding: 14px;
  border-radius: 14px;
  background:#0b1020;
  color:#d7def5;
  font-size:13px;
  line-height:1.45;

  overflow-x:auto;
  white-space:pre;
}

/* MathJax */
.bot mjx-container{
  max-width: 100% !important;
  overflow-x: auto !important;
  overflow-y: hidden !important;
  display:block;
  -webkit-overflow-scrolling: touch;
}

/* ===== status ===== */
.status{
  padding: 10px 12px;
  border-radius: 14px;
  background: rgba(255,243,205,.92);
  border: 1px solid rgba(0,0,0,.08);
  font-size: 13px;
  box-shadow: 0 10px 26px rgba(17,24,39,.08);
}

/* ===== composer ===== */
#composer{
  position: fixed;
  left: 0; right: 0; bottom: 0;
  z-index: 60;
  transform: translateY(calc(-1 * var(--kbd-offset)));
  background: rgba(246,247,251,.90);
  border-top: 1px solid rgba(17,24,39,.08);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

.composer-inner{
  max-width: 980px;
  margin: 0 auto;
  padding: 12px 14px;
  padding-bottom: calc(12px + env(safe-area-inset-bottom, 0px));
  display:flex;
  gap: 10px;
  align-items:flex-end;
}

.iconbtn{
  width: 44px;
  height: 44px;
  border-radius: 14px;
  border: 1px solid rgba(17,24,39,.10);
  background: rgba(255,255,255,.92);
  color: var(--text);
  display:grid;
  place-items:center;
  cursor:pointer;
  padding: 0;
}
.iconbtn .ico{ width: 20px; height: 20px; }
.iconbtn:active{ transform: translateY(1px); }

.textwrap{
  flex: 1;
  min-width: 0;
  border-radius: 16px;
  border: 1px solid rgba(17,24,39,.10);
  background: rgba(255,255,255,.96);
  box-shadow: 0 10px 26px rgba(17,24,39,.06);
  padding: 10px 12px;
}



#msg{
resize:none;
overflow-y:auto;
min-height:40px;
max-height:180px;
}

.sendbtn{
  width: 72px;
  height: 44px;
  border-radius: 14px;
  border: none;
  background: linear-gradient(135deg, var(--brand), var(--brand2));
  color:#fff;
  font-weight: 800;
  cursor:pointer;
  box-shadow: 0 14px 30px rgba(43,108,255,.20);
}
.sendbtn:disabled{ opacity: .6; cursor:not-allowed; }
.sendbtn:active{ transform: translateY(1px); }

/* dropdown */
.dropdown-menu{
  border-radius: 16px;
  border: 1px solid rgba(17,24,39,.10);
  box-shadow: 0 18px 50px rgba(17,24,39,.18);
  padding: 8px;
}
.dropdown-item{
  display:flex;
  align-items:center;
  gap: 10px;
  border-radius: 12px;
  padding: 10px 12px;
  font-size: 14px;
  color: var(--text);
}
.dropdown-item:active{ background: rgba(17,24,39,.06); }
.menu-ico{ width: 20px; height: 20px; flex: 0 0 auto; }

/* attachments */
.attachments{ margin-top: 8px; display:flex; gap: 8px; flex-wrap: wrap; }
.atchip{
  font-size: 12px;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(17,24,39,.06);
  border: 1px solid rgba(17,24,39,.10);
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}



/* image preview in attachments */
.atimg{
  position: relative;
  width: 84px;
  height: 84px;
  border-radius: 10px;
  border: 1px solid rgba(17,24,39,.12);
  overflow: hidden;
  background: rgba(17,24,39,.03);
}
.atimg img{
  width: 100%;
  height: 100%;
  object-fit: cover;
  display: block;
}
.atremove{
  position: absolute;
  top: 4px;
  right: 4px;
  width: 22px;
  height: 22px;
  border: 0;
  border-radius: 999px;
  background: rgba(0,0,0,.6);
  color: #fff;
  cursor: pointer;
  line-height: 22px;
  padding: 0;
}

/* images/files inside sent user messages */
.usertxt{ white-space: pre-wrap; }
.msgatts{
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 8px;
}
.msgimg{
  width: 180px;
  max-width: 100%;
  max-height: 240px;
  height: auto;
  object-fit: cover;
  border-radius: 12px;
  border: 1px solid rgba(255,255,255,.35);
  display: block;
}
.msgfile{
  font-size: 12px;
  padding: 6px 10px;
  border-radius: 999px;
  background: rgba(255,255,255,.16);
  border: 1px solid rgba(255,255,255,.22);
  color: #fff;
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* footer */
.hint{ font-size: 12px; color: rgba(15,23,42,.55); }

/* home button */
.home-btn{
  position: fixed;
  right: 16px;
  bottom: calc(var(--composer-h) + 16px + env(safe-area-inset-bottom, 0px));
  width: 44px;
  height: 44px;
  border-radius: 999px;
  display:grid;
  place-items:center;
  text-decoration:none;
  background: rgba(255,255,255,.92);
  border: 1px solid rgba(17,24,39,.10);
  box-shadow: 0 14px 36px rgba(17,24,39,.12);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  z-index: 55;
}
#loginBox{
  width:300px;
  margin:120px auto;
  text-align:center;
}

#loginBox input{
  width:100%;
  margin:5px 0;
  padding:10px;
}

#loginBox button{
  width:100%;
  padding:10px;
  margin-top:5px;
}

/* ===== responsive ===== */
@media (max-width: 640px){
  .wrap{ padding: 10px; gap: 10px; }
  .topbar{ top: 8px; padding: 10px 12px; }
  .topbar__avatar{ width: 38px; height: 38px; }
  .bubble{ font-size: 14px; }
  .composer-inner{ padding: 10px 10px; }
  .sendbtn{ width: 64px; }
  .home-btn{ right: 12px; }
}
/* layout chat + sidebar */

#chatApp{
display:none;
height:100dvh;
}

#chatApp > .d-flex{
height:100%;
width:100%;
}

/* sidebar */

.sidebar{
width:260px;
min-width:260px;
background:#fff;
border-right:1px solid #ddd;
height:100%;
overflow-y:auto;
transition: transform .3s ease;
}

/* main chat */

.flex-grow-1{
flex:1;
display:flex;
flex-direction:column;
min-width:0;
height:100%;
}

/* chat scroll */

#chat{
flex:1;
overflow:auto;
padding-bottom:140px;
}

.menu-btn{
z-index:3000;
position:relative;
}

/* mobile */
@media (max-width:768px){
.copy-btn {
    padding: 6px 10px;
    font-size: 13px;
}

#sidebar{
position:fixed;
top:0;
left:0;
width:260px;
height:100%;
background:#fff;
z-index:2000;

transform:translateX(-100%);
transition:transform .3s ease;
}

#sidebar.open{
transform:translateX(0);
}

}
.chat-history-item{
padding:10px 12px;
border-bottom:1px solid #eee;
cursor:pointer;
}

.chat-history-item:hover{
background:#f5f5f5;
}

.chat-history-item button{
border:none;
background:none;
font-size:18px;
z-index:2;
}
.chat-title{
cursor:pointer;
flex:1;
}
mjx-container{
font-size: 110%;
margin: 6px 0;
}
/*pre{
background:#0f172a;
color:#e5e7eb;
padding:14px
border-radius:10px;
overflow:auto;
font-size:13px;
}*/

pre code{
font-family: "JetBrains Mono", monospace;
}
pre{
position:relative;
background:#0f172a;
color:#e5e7eb;
padding:16px;
border-radius:10px;

overflow-x:auto;
max-width:100%;
white-space:pre;

-webkit-overflow-scrolling: touch;
}
.bot pre{
width:100%;
}

.copy-btn{
position:absolute;
top:8px;
right:8px;
background:#1e293b;
border:none;
padding:6px 8px;
border-radius:6px;
color:white;
cursor:pointer;
opacity:1;
transition:0.2s;
}

.password-box{
position:relative;
}

.password-box input{
padding-right:40px;
}

.toggle-pass{
position:absolute;
right:12px;
top:50%;
transform:translateY(-50%);
cursor:pointer;
font-size:18px;
color:#555;
}