* { box-sizing: border-box; }

body {
  margin: 0;
  background: #f7f4ef;
  color: #302d29;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

.app {
  max-width: 760px;
  margin: 0 auto;
  padding: 48px 20px;
}

h1 { font-size: 36px; margin: 0 0 8px; }
header p { color: #77716a; margin-bottom: 32px; }

.card {
  background: white;
  border: 1px solid #e9e1d8;
  border-radius: 18px;
  padding: 24px;
  margin: 16px 0;
}

.card small { color: #98735f; }
.card h2 { margin: 12px 0; }
.card p { color: #77716a; }

.status {
  display: inline-block;
  background: #f3e9df;
  border-radius: 20px;
  padding: 6px 12px;
  font-size: 13px;
}

.check { display: block; margin: 20px 0; }
.card label { display: block; }

textarea {
  display: block;
  width: 100%;
  min-height: 160px;
  margin-top: 10px;
  padding: 14px;
  border: 1px solid #d8d0c7;
  border-radius: 10px;
  font: inherit;
  resize: vertical;
}
#assignmentForm { display: grid; gap: 10px; }

#assignmentForm input {
  width: 100%;
  padding: 12px;
  border: 1px solid #d8d0c7;
  border-radius: 10px;
  font: inherit;
}

button {
  border: 0;
  border-radius: 10px;
  padding: 11px 18px;
  background: #795b49;
  color: white;
  cursor: pointer;
}

#assignmentView {
  margin-top: 24px;
  padding-top: 16px;
  border-top: 1px solid #e9e1d8;
}
.task-columns {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 28px;
}

.task-column {
  background: #faf8f5;
  border: 1px solid #e9e1d8;
  border-radius: 12px;
  padding: 16px;
}

.task-column h3 { margin: 0 0 12px; }

.task-item {
  display: block;
  width: 100%;
  margin: 8px 0;
  padding: 12px;
  text-align: left;
  background: white;
  color: #302d29;
  border: 1px solid #e9e1d8;
}

.task-item.active { border-color: #795b49; }
.task-item strong, .task-item span { display: block; }
.task-item span { margin-top: 5px; color: #77716a; font-size: 13px; }

@media (max-width: 600px) {
  .task-columns { grid-template-columns: 1fr; }
}
/* 未登录：只显示登录框 */
main > header,
main > section:not(#loginCard) {
  display: none;
}

/* 已登录：显示作业页面，但保留原本 hidden 的详情卡片 */
body.signed-in main > header,
body.signed-in main > section:not(#loginCard):not([hidden]) {
  display: block;
}

body.signed-in #loginCard {
  display: none;
}

#loginForm {
  display: grid;
  gap: 10px;
}

#loginForm input {
  padding: 12px;
  border: 1px solid #d8d0c7;
  border-radius: 10px;
  font: inherit;
}