:root {
  color-scheme: dark;
  --bg: #06111f;
  --panel: rgba(8, 28, 45, .94);
  --panel-2: #0c263b;
  --line: #174968;
  --line-soft: rgba(35, 215, 255, .2);
  --text: #e9f7ff;
  --muted: #8fb2c7;
  --cyan: #23d7ff;
  --green: #36e7a0;
  --accent: linear-gradient(135deg, var(--cyan), var(--green));
  --danger: #ff6b6b;
}
* { box-sizing: border-box; }
body { margin: 0; min-height: 100vh; overflow: hidden; background: radial-gradient(circle at 70% 10%, #123d61 0, transparent 36%), var(--bg); color: var(--text); font: 14px/1.55 "Microsoft YaHei", "PingFang SC", sans-serif; }
button, input, textarea { font: inherit; }
button { color: inherit; }
.hidden { display: none !important; }
.login-shell { min-height: 100vh; display: grid; place-items: center; padding: 24px; }
.login-card { width: min(410px, 100%); padding: 32px 34px; border: 1px solid var(--line); border-radius: 16px; background: rgba(6, 20, 34, .9); box-shadow: 0 24px 70px #0009, inset 0 0 35px rgba(35,215,255,.025); transition: border-color .25s, box-shadow .25s, transform .25s; }
.login-card:hover { border-color: rgba(35,215,255,.65); box-shadow: 0 24px 75px #000b, 0 0 24px rgba(35,215,255,.12), inset 0 0 35px rgba(54,231,160,.035); transform: translateY(-2px); }
.login-card h1 { margin: 18px 0 4px; font-size: 24px; }
.login-card p { color: var(--muted); margin: 0 0 26px; }
.login-card label { display: grid; gap: 7px; margin: 15px 0; color: #cbe6f5; }
.login-card input { width: 100%; padding: 12px 13px; color: var(--text); background: #061421; border: 1px solid var(--line); border-radius: 9px; outline: none; transition: border-color .2s, box-shadow .2s; }
.login-card input:hover, .login-card input:focus { border-color: var(--cyan); box-shadow: 0 0 0 2px rgba(35,215,255,.1), 0 0 16px rgba(35,215,255,.1); }
.login-card button { width: 100%; margin-top: 10px; padding: 12px; border: 0; border-radius: 9px; background: var(--accent); color: #04111b; font-weight: 700; cursor: pointer; transition: filter .2s, box-shadow .2s, transform .2s; }
.login-card button:hover { filter: brightness(1.08); box-shadow: 0 0 22px rgba(35,215,255,.3); transform: translateY(-1px); }
.error { min-height: 22px; margin-top: 10px; color: var(--danger); }
.logo-stage { display: grid; place-items: center; overflow: hidden; border: 1px solid transparent; transition: border-color .25s, box-shadow .25s, transform .25s; }
.brand-logo { display: block; width: 100%; height: 100%; object-fit: contain; mix-blend-mode: screen; transition: filter .25s, transform .25s; }
.logo-stage:hover { border-color: rgba(35,215,255,.65); box-shadow: 0 0 20px rgba(35,215,255,.16), inset 0 0 18px rgba(54,231,160,.08); transform: translateY(-1px); }
.logo-stage:hover .brand-logo { filter: drop-shadow(0 0 7px rgba(35,215,255,.75)) drop-shadow(0 0 12px rgba(54,231,160,.35)); transform: scale(1.025); }
.login-logo-stage { width: 178px; height: 116px; margin: 0 auto 8px; padding: 5px; border-radius: 12px; }
.sidebar-logo-stage { width: 52px; height: 42px; flex: 0 0 auto; border-radius: 8px; }
.hero-logo-stage { width: 180px; height: 126px; margin: auto; padding: 5px; border-radius: 14px; }
.app-shell { height: 100vh; display: grid; grid-template-columns: 270px 1fr; overflow: hidden; }
.sidebar { position: relative; min-width: 0; display: flex; flex-direction: column; background: rgba(4,15,27,.94); border-right: 1px solid var(--line); transition: border-color .25s, box-shadow .25s; }
.sidebar:hover { border-right-color: rgba(35,215,255,.7); box-shadow: 8px 0 24px rgba(35,215,255,.06); }
.sidebar-head { padding: 16px 14px; }
.brand { display: flex; align-items: center; gap: 10px; margin-bottom: 18px; }
.new-chat, .ghost { width: 100%; padding: 10px 12px; border: 1px solid var(--line); border-radius: 9px; background: var(--panel); text-align: left; cursor: pointer; transition: border-color .2s, box-shadow .2s, color .2s; }
.new-chat:hover, .ghost:hover { border-color: var(--cyan); color: #fff; box-shadow: 0 0 16px rgba(35,215,255,.12), inset 3px 0 0 var(--green); }
.conversation-list { flex: 1; overflow-y: auto; padding: 2px 10px 16px; }
.conversation { position: relative; display: flex; align-items: center; gap: 6px; margin: 3px 0; border: 1px solid transparent; border-radius: 9px; transition: border-color .2s, background .2s, box-shadow .2s; }
.conversation::before { content: ""; position: absolute; left: -1px; top: 18%; bottom: 18%; width: 2px; border-radius: 2px; background: linear-gradient(var(--cyan), var(--green)); opacity: 0; box-shadow: 0 0 9px var(--cyan); transition: opacity .2s; }
.conversation:hover, .conversation.active { border-color: var(--line-soft); background: var(--panel-2); box-shadow: 0 0 14px rgba(35,215,255,.06); }
.conversation:hover::before, .conversation.active::before { opacity: 1; }
.conversation button.title { flex: 1; min-width: 0; padding: 9px 10px; border: 0; background: transparent; color: #dfe2e6; overflow: hidden; white-space: nowrap; text-overflow: ellipsis; text-align: left; cursor: pointer; }
.conversation button.delete { opacity: 0; border: 0; padding: 7px; background: transparent; color: var(--muted); cursor: pointer; }
.conversation:hover button.delete { opacity: 1; }
.sidebar-foot { padding: 14px; border-top: 1px solid var(--line); }
.model-line { display: flex; align-items: center; gap: 8px; margin-bottom: 12px; color: var(--muted); font-size: 12px; }
.status-dot { width: 8px; height: 8px; border-radius: 50%; background: #6b7280; }
.status-dot.online { background: var(--green); box-shadow: 0 0 10px #37c97788; }
.main { min-width: 0; min-height: 0; height: 100vh; overflow: hidden; display: grid; grid-template-rows: auto minmax(0, 1fr) auto; background: var(--bg); }
.topbar { height: 62px; display: flex; align-items: center; gap: 12px; padding: 0 22px; border-bottom: 1px solid var(--line); background: rgba(6,17,31,.52); transition: border-color .25s, box-shadow .25s; }
.topbar:hover { border-bottom-color: rgba(35,215,255,.7); box-shadow: 0 7px 20px rgba(35,215,255,.055); }
.topbar div { display: grid; }
.topbar small { color: var(--muted); }
.menu-toggle { display: none; border: 0; background: transparent; font-size: 20px; }
.messages { min-height: 0; overflow-y: auto; overscroll-behavior: contain; padding: 34px max(24px, calc((100% - 820px)/2)); }
.welcome { max-width: 580px; margin: 12vh auto 0; text-align: center; }
.welcome h2 { margin: 16px 0 5px; font-size: 28px; }
.welcome p { color: var(--muted); }
.message { display: grid; grid-template-columns: 34px 1fr; gap: 12px; margin: 0 0 28px; }
.avatar { width: 32px; height: 32px; display: grid; place-items: center; border: 1px solid var(--line); border-radius: 9px; background: var(--panel-2); color: var(--cyan); font-size: 12px; font-weight: 700; transition: border-color .2s, box-shadow .2s; }
.message:hover .avatar { border-color: var(--cyan); box-shadow: 0 0 12px rgba(35,215,255,.18); }
.message.user .avatar { background: #11354c; color: var(--green); }
.message-content { min-width: 0; padding-top: 5px; white-space: pre-wrap; word-break: break-word; }
.message-content pre { overflow-x: auto; padding: 14px; border: 1px solid var(--line); border-radius: 10px; background: #090a0c; }
.cursor::after { content: ""; display: inline-block; width: 7px; height: 16px; margin-left: 3px; background: #ddd; vertical-align: -3px; animation: blink 1s steps(1) infinite; }
@keyframes blink { 50% { opacity: 0; } }
.composer-wrap { padding: 0 max(18px, calc((100% - 820px)/2)) 14px; background: linear-gradient(transparent, var(--bg) 26%); }
.composer { display: flex; align-items: flex-end; gap: 10px; padding: 10px; border: 1px solid var(--line); border-radius: 16px; background: var(--panel); box-shadow: 0 10px 30px #0005; transition: border-color .2s, box-shadow .2s; }
.composer:hover, .composer:focus-within { border-color: var(--cyan); box-shadow: 0 10px 30px #0006, 0 0 20px rgba(35,215,255,.1), inset 0 -2px 0 rgba(54,231,160,.35); }
.composer textarea { flex: 1; max-height: 180px; resize: none; padding: 8px 4px; color: var(--text); background: transparent; border: 0; outline: none; }
.attach, .send { width: 36px; height: 36px; display: grid; place-items: center; border: 0; border-radius: 10px; cursor: pointer; }
.attach { color: #d5eff9; background: var(--panel-2); border: 1px solid var(--line); font-size: 22px; transition: border-color .2s, box-shadow .2s; }
.attach:hover { border-color: var(--cyan); box-shadow: 0 0 12px rgba(35,215,255,.18); }
.send { background: var(--accent); color: #04111b; font-size: 20px; font-weight: 800; transition: box-shadow .2s, transform .2s; }
.send:hover:not(:disabled) { box-shadow: 0 0 17px rgba(35,215,255,.35); transform: translateY(-1px); }
.send:disabled { opacity: .4; cursor: default; }
.hint { margin: 8px 0 0; color: #747983; font-size: 11px; text-align: center; }
.attachment-bar { display: flex; gap: 8px; margin-bottom: 8px; }
.attachment-chip { padding: 7px 10px; border: 1px solid var(--line); border-radius: 9px; background: var(--panel); color: #dfeaf0; transition: border-color .2s, box-shadow .2s; }
.attachment-chip:hover { border-color: var(--green); box-shadow: 0 0 13px rgba(54,231,160,.14); }
@media (max-width: 760px) {
  .app-shell { grid-template-columns: 1fr; }
  .sidebar { position: fixed; z-index: 10; inset: 0 auto 0 0; width: 280px; transform: translateX(-100%); transition: transform .2s; box-shadow: 16px 0 40px #0008; }
  .sidebar.open { transform: translateX(0); }
  .menu-toggle { display: block; }
  .messages { padding: 24px 18px; }
}