/* ============================================================================
   Design tokens dùng chung cho toàn site Hán Ngữ Tuệ Văn.
   Tái sử dụng nguyên vẹn bộ CSS variables + reset cơ bản từ project HSK4
   mock test hiện tại — giữ nhất quán hình ảnh thương hiệu (tông xanh lá).
   ============================================================================ */

:root {
  --green: #0f9d58;
  --green-dark: #0b7a43;
  --green-light: #e6f6ec;
  --bg: #f5faf7;
  --white: #ffffff;
  --text: #1b2a22;
  --muted: #5b6b62;
  --red: #d64545;
  --radius: 16px;
  --shadow: 0 4px 18px rgba(15, 157, 88, 0.10);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "PingFang SC", "Microsoft YaHei", "Noto Sans SC", system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
}

.container {
  max-width: 960px;
  margin: 0 auto;
  padding: 24px 16px 80px;
}

.card {
  background: var(--white);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 32px;
}

.btn {
  display: inline-block;
  background: var(--green);
  color: #fff;
  border: none;
  border-radius: 999px;
  padding: 14px 28px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  transition: transform .1s, background .15s;
}
.btn:hover { background: var(--green-dark); }
.btn:active { transform: scale(.97); }
.btn.secondary { background: #fff; color: var(--green-dark); border: 2px solid var(--green); }
.btn.danger { background: var(--red); }
.btn.block { width: 100%; }
.btn:disabled { opacity: .5; cursor: not-allowed; }

.error-msg { color: var(--red); margin: 10px 0; font-size: 14px; }
.small-muted { color: var(--muted); font-size: 13px; }
.hidden { display: none !important; }
a.linklike { color: var(--green-dark); cursor: pointer; font-weight: 600; }

/* ---- Header / Nav (dùng bởi shared/nav.js) ---- */
#site-header {
  background: var(--white);
  box-shadow: 0 2px 10px rgba(15, 157, 88, 0.06);
  position: sticky;
  top: 0;
  z-index: 10;
}
.nav-inner {
  display: flex;
  align-items: center;
  gap: 20px;
  padding-top: 14px;
  padding-bottom: 14px;
  flex-wrap: wrap;
}
.brand {
  font-weight: 800;
  font-size: 18px;
  color: var(--green-dark);
  text-decoration: none;
  margin-right: auto;
}
.nav-links {
  display: flex;
  gap: 4px;
  flex-wrap: wrap;
}
.nav-link {
  color: var(--text);
  text-decoration: none;
  font-size: 14px;
  font-weight: 600;
  padding: 8px 12px;
  border-radius: 999px;
}
.nav-link:hover { background: var(--green-light); }
.nav-link.active { background: var(--green-light); color: var(--green-dark); }
.nav-auth { display: flex; align-items: center; gap: 8px; }
.btn.small { padding: 8px 18px; font-size: 14px; }

/* ---- Footer ---- */
#site-footer {
  border-top: 1px solid #e2ede6;
  margin-top: 40px;
}
.footer-inner {
  padding-top: 24px;
  padding-bottom: 24px;
  text-align: center;
}

/* ---- Grid dùng chung cho các trang khung (Khóa học/Ôn tập/Bài tập/Thi...) ---- */
.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 16px;
  margin-top: 20px;
}
.badge {
  display: inline-block;
  background: var(--green-light);
  color: var(--green-dark);
  font-size: 12px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 999px;
  margin-bottom: 8px;
}
.badge.locked { background: #fdecec; color: var(--red); }
.page-hero { padding: 28px 0 8px; }
.page-hero h1 { font-size: 28px; margin-bottom: 6px; }
.note-box {
  background: var(--green-light);
  border-radius: var(--radius);
  padding: 16px 20px;
  font-size: 14px;
  color: var(--green-dark);
  margin: 20px 0;
}

/* ---- Màn hình làm bài (tái sử dụng từ HSK4 mock test) ---- */
.exam-header { position: sticky; top: 0; background: var(--white); z-index: 10; box-shadow: 0 2px 8px rgba(0,0,0,.06); }
.exam-header-inner { max-width: 960px; margin: 0 auto; padding: 12px 16px; display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
.timer { font-size: 22px; font-weight: 700; color: var(--green-dark); background: var(--green-light); padding: 6px 16px; border-radius: 999px; }
.timer.warn { color: var(--red); background: #fdeaea; }
.tabs { display: flex; gap: 8px; }
.tab { padding: 8px 16px; border-radius: 999px; background: var(--bg); cursor: pointer; font-weight: 600; color: var(--muted); }
.tab.active { background: var(--green); color: #fff; }
.qnav { display: flex; flex-wrap: wrap; gap: 6px; padding: 14px 16px; background: var(--white); border-bottom: 1px solid #eef3f0; }
.qnav button { width: 34px; height: 34px; border-radius: 8px; border: 1px solid #d7e9de; background: #fff; cursor: pointer; font-size: 13px; color: var(--text); }
.qnav button.answered { background: var(--green-light); border-color: var(--green); }
.qnav button.current { background: var(--green); color: #fff; }
.question-block { background: var(--white); border-radius: var(--radius); box-shadow: var(--shadow); padding: 24px; margin: 16px 0; }
.qid { display: inline-block; background: var(--green); color: #fff; border-radius: 8px; padding: 2px 10px; font-weight: 700; margin-right: 8px; }
.options { display: grid; gap: 10px; margin-top: 14px; }
.option { border: 2px solid #e3eee7; border-radius: 12px; padding: 12px 16px; cursor: pointer; display: flex; gap: 10px; align-items: center; }
.option:hover { border-color: var(--green); }
.option.selected { border-color: var(--green); background: var(--green-light); font-weight: 600; }
.option .key { font-weight: 700; color: var(--green-dark); min-width: 20px; }
.passage { background: var(--bg); border-radius: 12px; padding: 16px; margin-bottom: 14px; line-height: 1.9; color: var(--text); }
.cloze-blank { display: inline-block; font-weight: 700; color: var(--muted); padding: 0 2px; }
.cloze-blank.current { color: var(--green-dark); background: var(--green-light); border-radius: 6px; padding: 0 6px; }
.wordbank { display: flex; flex-wrap: wrap; gap: 8px; margin-bottom: 16px; }
.instruction { color: var(--muted); font-size: 14px; margin-bottom: 10px; }
textarea { width: 100%; min-height: 70px; border: 2px solid #e3eee7; border-radius: 12px; padding: 12px; font-size: 16px; font-family: inherit; resize: vertical; }
textarea:focus { outline: none; border-color: var(--green); }
.words-pool { display: flex; flex-wrap: wrap; gap: 8px; margin: 10px 0; }
.words-pool span { background: var(--green-light); border-radius: 8px; padding: 6px 12px; font-weight: 600; }
img.qimg { max-width: 260px; border-radius: 12px; display: block; margin-bottom: 14px; box-shadow: 0 2px 10px rgba(0,0,0,.08); }
.footer-actions { position: sticky; bottom: 0; background: var(--white); border-top: 1px solid #eef3f0; padding: 14px 16px; display: flex; justify-content: space-between; gap: 12px; }
.modal-overlay { position: fixed; inset: 0; background: rgba(0,0,0,.4); display: flex; align-items: center; justify-content: center; z-index: 100; }
.modal { background: #fff; border-radius: var(--radius); padding: 28px; max-width: 400px; text-align: center; }
.modal .btn-row { display: flex; gap: 10px; margin-top: 20px; }
.modal .btn-row .btn { flex: 1; }
.score-grid { display: grid; grid-template-columns: repeat(auto-fit,minmax(140px,1fr)); gap: 14px; margin: 20px 0; }
.score-card { background: var(--green-light); border-radius: 14px; padding: 16px; text-align: center; }
.score-card .num { font-size: 28px; font-weight: 800; color: var(--green-dark); }
.score-card .lbl { color: var(--muted); font-size: 13px; }
.status-pill { padding: 3px 10px; border-radius: 999px; font-size: 12px; font-weight: 700; }
.status-in_progress { background: #fff4d6; color: #8a6d00; }
.status-submitted, .status-auto_submitted { background: var(--green-light); color: var(--green-dark); }
.status-pending { background: #fff4d6; color: #8a6d00; }