:root {
  --bg: #fbf8f1;
  --ink: #2b2b2b;
  --accent: #8a6d3b;
  --accent-soft: #efe7d6;
  --pen: #f3ece0;
  --you: #e7eef5;
  --line: #e3dccb;
}
* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--ink);
}
.hidden { display: none !important; }
.dim { color: #9a8e78; font-size: .85rem; }

/* ---- Auth ---- */
.auth { display: grid; place-items: center; min-height: 100vh; padding: 1.5rem; }
.card {
  background: #fff; border: 1px solid var(--line); border-radius: 16px;
  padding: 2.2rem; width: 100%; max-width: 380px; box-shadow: 0 10px 40px rgba(120,100,60,.08);
}
.card h1 { margin: 0 0 .3rem; font-size: 2rem; }
.tagline { color: #5a4a32; line-height: 1.5; margin: 0 0 1.5rem; }
.tabs { display: flex; gap: .5rem; margin-bottom: 1rem; }
.tab {
  flex: 1; padding: .55rem; border: 1px solid var(--line); background: #faf6ee;
  border-radius: 9px; cursor: pointer; font-size: .92rem; color: #6a5d45;
}
.tab.active { background: var(--accent); color: #fff; border-color: var(--accent); }
form { display: flex; flex-direction: column; gap: .7rem; }
input, textarea {
  font: inherit; padding: .7rem .85rem; border: 1px solid var(--line);
  border-radius: 9px; background: #fff; color: var(--ink);
}
input:focus, textarea:focus { outline: 2px solid var(--accent-soft); border-color: var(--accent); }
button[type=submit] {
  padding: .75rem; border: none; border-radius: 9px; background: var(--accent);
  color: #fff; font-weight: 600; cursor: pointer;
}
button[type=submit]:hover { filter: brightness(1.05); }
.error { color: #b3261e; min-height: 1.2em; font-size: .9rem; margin: .6rem 0 0; }

/* ---- App ---- */
.app { display: flex; flex-direction: column; height: 100vh; max-width: 760px; margin: 0 auto; }
.topbar {
  display: flex; align-items: center; justify-content: space-between;
  padding: .8rem 1rem; border-bottom: 1px solid var(--line); background: #fffdf8;
}
.brand { font-size: 1.2rem; font-weight: 700; }
.actions { display: flex; align-items: center; gap: .6rem; }
.book-title { color: #9a8e78; font-size: .8rem; font-style: italic; }
.ghost {
  background: none; border: 1px solid var(--line); border-radius: 8px;
  padding: .4rem .7rem; cursor: pointer; color: var(--accent); text-decoration: none; font-size: .85rem;
}
.ghost:hover { background: var(--accent-soft); }

.thread { flex: 1; overflow-y: auto; padding: 1.5rem 1rem; display: flex; flex-direction: column; gap: 1rem; }
.msg { max-width: 80%; padding: .8rem 1rem; border-radius: 16px; line-height: 1.55; white-space: pre-wrap; }
.msg.pen { background: var(--pen); border: 1px solid var(--line); align-self: flex-start; border-bottom-left-radius: 4px; }
.msg.you { background: var(--you); align-self: flex-end; border-bottom-right-radius: 4px; }
.msg.typing { color: #9a8e78; font-style: italic; }

.composer { display: flex; gap: .6rem; padding: .8rem 1rem; border-top: 1px solid var(--line); background: #fffdf8; }
.composer textarea { flex: 1; resize: none; max-height: 160px; }
.composer button {
  border: none; border-radius: 10px; background: var(--accent); color: #fff;
  padding: 0 1.3rem; font-weight: 600; cursor: pointer;
}
.composer button:disabled { opacity: .5; cursor: default; }

.toast {
  align-self: center; background: #efe7d6; color: #6a5326; border: 1px solid var(--line);
  padding: .45rem .9rem; border-radius: 20px; font-size: .85rem; margin: 0 1rem;
  transition: opacity .4s;
}