/* Coach — tối giản, sang, "ánh sáng + khoảng trống" (tinh-art). Tối ưu iPhone. */
:root {
  --bg: #0f1216;
  --panel: #161b22;
  --ink: #e9eef5;
  --muted: #8a94a3;
  --me: #1f6feb;          /* tin nhắn của học viên */
  --coach: #1b2430;       /* tin nhắn của coach */
  --accent: #54d6a6;      /* anchor: xanh ngọc ấm */
  --line: #232b36;
  --radius: 20px;
  --safe-b: env(safe-area-inset-bottom, 0px);
}
* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }
html, body { height: 100%; margin: 0; }
body {
  background: var(--bg); color: var(--ink);
  font: 16px/1.5 -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, system-ui, sans-serif;
  display: flex; flex-direction: column;
  padding-top: env(safe-area-inset-top, 0px);
}

.top {
  display: flex; align-items: center; justify-content: space-between;
  padding: 14px 18px; border-bottom: 1px solid var(--line);
  position: sticky; top: 0; background: rgba(15,18,22,.85); backdrop-filter: blur(12px); z-index: 5;
}
.brand { display: flex; align-items: center; gap: 12px; }
.dot { width: 12px; height: 12px; border-radius: 50%; background: var(--accent);
  box-shadow: 0 0 14px var(--accent); flex: none; }
.top h1 { font-size: 18px; margin: 0; letter-spacing: .2px; }
.top p { margin: 0; font-size: 12px; color: var(--muted); }

.log { flex: 1; overflow-y: auto; padding: 22px 16px 8px; display: flex; flex-direction: column; gap: 14px; }
.msg { max-width: 84%; padding: 12px 15px; border-radius: var(--radius); white-space: pre-wrap; word-wrap: break-word; }
.msg.me { align-self: flex-end; background: var(--me); border-bottom-right-radius: 6px; }
.msg.coach { align-self: flex-start; background: var(--coach); border-bottom-left-radius: 6px; border: 1px solid var(--line); }
.msg .fix { display: block; color: var(--accent); font-weight: 600; margin-bottom: 4px; }
.msg .vi { display: block; color: var(--muted); font-size: 14px; margin-top: 8px;
  padding-top: 8px; border-top: 1px dashed var(--line); }
.msg .replay { margin-top: 8px; font-size: 12px; color: var(--muted); background: none; border: 1px solid var(--line);
  border-radius: 999px; padding: 4px 12px; cursor: pointer; }
.msg.coach.speaking { border-color: var(--accent); }
.typing { align-self: flex-start; color: var(--muted); font-style: italic; padding: 4px 8px; }

.hint { color: var(--muted); font-size: 13px; text-align: center; padding: 4px 24px 10px; }
.hint.strong { color: var(--accent); font-size: 14px; font-weight: 600; }

.bar {
  display: flex; align-items: center; gap: 10px; padding: 12px 14px calc(12px + var(--safe-b));
  border-top: 1px solid var(--line); background: var(--bg);
}
.bar input {
  flex: 1; background: var(--panel); border: 1px solid var(--line); color: var(--ink);
  border-radius: 999px; padding: 13px 18px; font-size: 16px; outline: none;
}
.bar input:focus { border-color: var(--accent); }
.mic, .send {
  flex: none; width: 48px; height: 48px; border-radius: 50%; border: none; cursor: pointer;
  font-size: 20px; display: grid; place-items: center;
}
.mic { background: var(--panel); border: 1px solid var(--line); }
.mic.live { background: var(--accent); color: #04110b; animation: pulse 1.1s infinite; }
.send { background: var(--accent); color: #04110b; font-weight: 700; }
@keyframes pulse { 0%,100% { transform: scale(1); } 50% { transform: scale(1.08); } }

dialog#menu { background: var(--panel); color: var(--ink); border: 1px solid var(--line);
  border-radius: 18px; padding: 20px; width: min(92vw, 380px); }
dialog#menu::backdrop { background: rgba(0,0,0,.5); }
dialog h2 { margin: 0 0 14px; font-size: 16px; }
.row { display: flex; align-items: center; justify-content: space-between; gap: 14px; padding: 10px 0; border-bottom: 1px solid var(--line); }
.meminfo { font-size: 12px; color: var(--muted); padding: 12px 0; }
.actions { display: flex; gap: 10px; justify-content: flex-end; margin-top: 8px; }
button.ghost { background: none; border: 1px solid var(--line); color: var(--ink); border-radius: 12px; padding: 8px 14px; cursor: pointer; }
button.danger { background: #3a1d22; border: 1px solid #5a2a30; color: #ff9aa6; border-radius: 12px; padding: 8px 14px; cursor: pointer; }