:root {
  --bg: #f5f7fb;
  --panel: #ffffff;
  --line: #d7ddea;
  --ink: #1f2a44;
  --muted: #5f6b85;
  --primary: #3a7afe;
  --danger: #d64545;
}
* {
  box-sizing: border-box;
  font-family: "SF Pro Text","PingFang SC","Helvetica Neue",Arial,sans-serif;
}
body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  min-height: 100vh;
}
.site {
  max-width: 1280px;
  margin: 0 auto;
  padding: 14px 18px 18px;
}
.topbar {
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 14px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 12px;
  margin-bottom: 12px;
  box-shadow: 0 4px 18px rgba(28, 43, 79, 0.06);
}
.title {
  margin: 0;
  font-size: 22px;
  font-weight: 700;
}
.auth {
  display: flex;
  align-items: center;
  gap: 8px;
}
.user-badge {
  font-size: 13px;
  color: var(--muted);
  padding: 4px 10px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: #f8faff;
  display: none;
}
button, .subject-tab {
  border: 1px solid var(--line);
  background: #fff;
  border-radius: 8px;
  padding: 8px 10px;
  font-size: 13px;
  cursor: pointer;
  color: var(--ink);
  text-decoration: none;
  display: inline-block;
}
button.primary, .subject-tab.active {
  border-color: var(--primary);
  color: #fff;
  background: var(--primary);
}
button.danger {
  border-color: var(--danger);
  color: var(--danger);
  background: #fff;
}
.subject-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 12px;
}
.modal-wrap {
  position: fixed;
  inset: 0;
  display: none;
  align-items: center;
  justify-content: center;
  background: rgba(20, 30, 54, 0.34);
  z-index: 20;
}
.modal-wrap.show {
  display: flex;
}
.modal {
  width: min(420px, calc(100vw - 24px));
  background: #fff;
  border: 1px solid var(--line);
  border-radius: 12px;
  box-shadow: 0 10px 28px rgba(28, 43, 79, 0.2);
  padding: 14px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.modal-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 16px;
  font-weight: 600;
}
.field {
  display: flex;
  flex-direction: column;
  gap: 6px;
  font-size: 13px;
  color: var(--muted);
}
.field input {
  border: 1px solid var(--line);
  border-radius: 8px;
  padding: 9px 10px;
  font-size: 14px;
  outline: none;
}
.msg {
  min-height: 18px;
  font-size: 12px;
  color: var(--danger);
}
.modal-foot {
  display: flex;
  justify-content: flex-end;
  gap: 8px;
}