/*
  老师端 h5 样式：手机上改作业，电脑上开会，两种都要能用。
  只做排版，不做主题系统——大屏的配色在 board-web 里。
*/
:root {
  --bg: #f5f6f4;
  --card: #ffffff;
  --line: #dfe3df;
  --text: #23302b;
  --muted: #6f7c76;
  --brand: #2f6049;
  --brand-ink: #ffffff;
  --warn: #c0392b;
  --radius: 10px;
}

* { box-sizing: border-box; }

/* hidden 属性必须赢过 .tabs/.screen 这些带 display 的规则 */
[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font: 15px/1.55 -apple-system, "Segoe UI", "Microsoft YaHei", system-ui, sans-serif;
}

.topbar {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 10px 16px;
  background: var(--brand);
  color: var(--brand-ink);
  position: sticky;
  top: 0;
  z-index: 5;
}

.brand { font-weight: 600; letter-spacing: .04em; }
.who { flex: 1; font-size: 14px; opacity: .92; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.link {
  background: none;
  border: 0;
  color: inherit;
  font: inherit;
  opacity: .85;
  cursor: pointer;
  padding: 4px 6px;
}
.link:hover { opacity: 1; text-decoration: underline; }

.tabs {
  display: flex;
  gap: 4px;
  padding: 8px 12px 0;
  background: var(--brand);
}
.tab {
  border: 0;
  border-radius: 8px 8px 0 0;
  background: rgba(255, 255, 255, .14);
  color: var(--brand-ink);
  padding: 8px 18px;
  font: inherit;
  cursor: pointer;
}
.tab.is-on { background: var(--bg); color: var(--text); }

main { padding: 16px; }

/* 登录屏：内容整体水平居中，宽度与表单一致（.form 的 420px） */
#screen-login { max-width: 420px; margin: 0 auto; }

.screen[hidden] { display: none; }
.welcome { font-size: 20px; margin: 8px 0 4px; }
.note { color: var(--muted); font-size: 13px; margin: 6px 0; }

.card {
  background: var(--card);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  padding: 14px 16px;
  margin-bottom: 12px;
}
.card-title { font-size: 15px; margin: 0 0 10px; }

/* 登录 */
.panes { margin-top: 14px; }
.pane { display: none; }
.pane.is-on { display: block; }

/* 首屏只有两个选择：创建班级 / 进入班级 */
.entry { display: grid; gap: 12px; grid-template-columns: repeat(2, minmax(0, 1fr)); margin-top: 16px; }
.entry-btn {
  display: grid;
  gap: 4px;
  text-align: left;
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: var(--radius);
  background: var(--card);
  color: var(--text);
  font: inherit;
  cursor: pointer;
}
.entry-btn:hover { border-color: var(--brand); }
.entry-title { font-size: 16px; font-weight: 600; color: var(--brand); }
.entry-note { font-size: 13px; color: var(--muted); }

.link.back { color: var(--brand); opacity: .7; font-size: 13px; padding: 0; margin-bottom: 10px; }

.class-code {
  margin: 14px 0 0;
  font-size: 20px;
  font-weight: 600;
  letter-spacing: .12em;
  color: var(--brand);
}

.form { display: grid; gap: 10px; max-width: 420px; }
.form label { display: grid; gap: 6px; font-size: 13px; color: var(--muted); }

input, textarea, select {
  width: 100%;
  padding: 9px 10px;
  border: 1px solid var(--line);
  border-radius: 8px;
  background: #fff;
  color: var(--text);
  font: inherit;
}
input:focus, textarea:focus, select:focus { outline: 2px solid rgba(47, 96, 73, .35); border-color: var(--brand); }
textarea { resize: vertical; }

button.primary {
  padding: 10px 16px;
  border: 0;
  border-radius: 8px;
  background: var(--brand);
  color: var(--brand-ink);
  font: inherit;
  cursor: pointer;
}
button.primary:disabled { opacity: .55; cursor: default; }
button.ghost {
  padding: 8px 14px;
  border: 1px solid var(--brand);
  border-radius: 8px;
  background: #fff;
  color: var(--brand);
  font: inherit;
  cursor: pointer;
}

.pane-switch { display: flex; flex-wrap: wrap; gap: 14px; margin-top: 14px; }
.pane-switch .link { color: var(--brand); opacity: .7; font-size: 13px; }
.pane-switch .link.is-on { opacity: 1; font-weight: 600; }

.msg { margin: 12px 0 0; font-size: 13px; color: var(--muted); }
.msg.is-error { color: var(--warn); }

/* 发布 */
.split { display: grid; gap: 12px; grid-template-columns: minmax(0, 1fr) 300px; align-items: start; }
@media (max-width: 860px) { .split { grid-template-columns: minmax(0, 1fr); } }

.editor { display: grid; gap: 0; }
.aside { position: sticky; top: 60px; }
.device-list { font-size: 13px; color: var(--muted); margin: 8px 0 0; }
.inline { display: flex; gap: 8px; }
.inline input { flex: 1; }

.savebar { display: flex; align-items: center; gap: 12px; }
.save-state { flex: 1; font-size: 13px; color: var(--muted); }

/* 任课老师与登录码 */
.teacher-list { list-style: none; margin: 10px 0 0; padding: 0; display: grid; gap: 8px; }
.teacher-row { display: flex; align-items: center; gap: 8px; font-size: 13px; }
.teacher-name { flex: 1; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.teacher-code { font-family: ui-monospace, Consolas, monospace; letter-spacing: .1em; color: var(--brand); }
.teacher-code.is-off { color: var(--muted); }

.field { display: grid; gap: 5px; margin-bottom: 10px; }
.field-label { font-size: 13px; color: var(--muted); }
.field-count { font-size: 12px; color: var(--muted); text-align: right; }
.field-count.is-over { color: var(--warn); font-weight: 600; }
.field-count.is-over::after { content: " 超了"; }

/* 预览 */
.screen-preview .frame-wrap {
  border: 1px solid var(--line);
  border-radius: var(--radius);
  overflow: hidden;
  background: #000;
  aspect-ratio: 16 / 9;
}
.screen-preview iframe { display: block; width: 100%; height: 100%; border: 0; }

.toast {
  position: fixed;
  left: 50%;
  bottom: 28px;
  transform: translateX(-50%);
  background: rgba(30, 42, 37, .94);
  color: #fff;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 14px;
  max-width: min(90vw, 520px);
  z-index: 20;
}
.toast.is-error { background: rgba(160, 48, 38, .96); }