body {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1.5rem;
}

.login-card {
  width: 100%;
  max-width: 380px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 2rem 1.75rem;
  box-shadow: var(--shadow);
}

.login-hdr {
  text-align: center;
  margin-bottom: 1.5rem;
}
.login-hdr .course-name {
  font-size: 18px;
  margin-bottom: 8px;
}

.login-title {
  font-size: 14px;
  color: var(--text-secondary);
  text-align: center;
  margin-bottom: 1.25rem;
}

.error-msg {
  background: var(--error-bg);
  border: 1px solid var(--error-border);
  color: var(--error-text);
  padding: 8px 12px;
  border-radius: 8px;
  font-size: 13px;
  margin-bottom: 1rem;
  display: none;
}
.error-msg.show { display: block; }

.field {
  margin-bottom: 0.85rem;
}
.field label {
  display: block;
  font-size: 12px;
  color: var(--text-secondary);
  margin-bottom: 5px;
  font-weight: 500;
}
.field input {
  width: 100%;
  padding: 9px 12px;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: var(--bg);
  color: var(--text);
  font-size: 14px;
  font-family: inherit;
  outline: none;
  transition: border-color 0.15s;
}
.field input:focus {
  border-color: var(--accent);
}

.login-btn {
  width: 100%;
  padding: 10px;
  margin-top: 0.5rem;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: #fff;
  font-size: 14px;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.15s;
}
.login-btn:hover {
  background: var(--accent-hover);
}