:root {
  --bg: #0f172a;
  --card: #ffffff;
  --primary: #0ea5e9;
  --primary-d: #0284c7;
  --text: #0f172a;
  --muted: #64748b;
  --border: #e2e8f0;
  --ok: #16a34a;
  --radius: 14px;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  padding: 20px 14px 40px;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: linear-gradient(160deg, #0f172a 0%, #1e293b 60%, #0ea5e9 160%);
  color: var(--text);
}

.card {
  width: 100%;
  max-width: 560px;
  background: var(--card);
  border-radius: var(--radius);
  box-shadow: 0 18px 50px rgba(0, 0, 0, 0.35);
  padding: 24px 22px;
}

.head h1 { margin: 0 0 4px; font-size: 1.3rem; }
.head .sub { margin: 0 0 18px; color: var(--muted); font-size: 0.9rem; }

/* Thanh tab chuyển chức năng */
.tabs {
  display: flex; gap: 6px; margin-bottom: 18px;
  background: #f1f5f9; padding: 4px; border-radius: 10px;
}
.tab {
  flex: 1; padding: 10px 8px; border: none; border-radius: 8px;
  background: transparent; color: var(--muted);
  font-weight: 600; font-size: 0.92rem; cursor: pointer;
}
.tab.active { background: #fff; color: var(--primary-d); box-shadow: 0 1px 4px rgba(0, 0, 0, 0.1); }

/* Nhãn trái — ô nhập phải, cùng 1 dòng cho gọn */
.field { display: flex; align-items: center; gap: 10px; margin-bottom: 12px; }
.field > span { flex: 0 0 132px; font-size: 0.88rem; font-weight: 600; line-height: 1.25; }
.field .optional { display: block; color: var(--muted); font-weight: 400; font-style: normal; font-size: 0.72rem; }

/* Ô khen: textarea cao hơn, nhãn căn lên đầu dòng */
.field-praise { align-items: flex-start; }
.field-praise textarea {
  flex: 1; min-width: 0; height: 88px; resize: vertical;
  padding: 10px 12px; font-size: 0.95rem;
}

select, input[type="text"] {
  flex: 1;
  min-width: 0;
  padding: 11px 12px;
  font-size: 1rem;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #f8fafc;
  color: var(--text);
}
select:focus, input:focus, textarea:focus { outline: 2px solid var(--primary); background: #fff; }

.btn-primary {
  width: 100%;
  padding: 14px;
  font-size: 1.05rem;
  font-weight: 700;
  color: #fff;
  background: var(--primary);
  border: none;
  border-radius: 10px;
  cursor: pointer;
}
.btn-primary:active { background: var(--primary-d); }
.btn-primary:disabled { background: #94a3b8; cursor: not-allowed; }

.result-container { margin-top: 20px; border-top: 1px solid var(--border); padding-top: 16px; }
.result-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 10px; }
.result-header h3 { margin: 0; font-size: 1rem; }

.btn-copy {
  padding: 8px 16px;
  font-size: 0.85rem;
  font-weight: 600;
  color: #fff;
  background: var(--ok);
  border: none;
  border-radius: 8px;
  cursor: pointer;
}
.btn-copy:active { opacity: 0.85; }

textarea {
  width: 100%;
  height: 240px;
  resize: vertical;
  padding: 12px;
  font-size: 1rem;
  font-family: inherit;
  line-height: 1.5;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: #f8fafc;
  color: var(--text);
}

.footer {
  margin-top: 20px;
  padding-top: 14px;
  border-top: 1px solid var(--border);
  text-align: center;
  font-size: 0.8rem;
  color: var(--muted);
}
.footer a { color: var(--primary-d); font-weight: 600; text-decoration: none; }
.footer a:hover { text-decoration: underline; }

.toast {
  position: fixed;
  left: 50%;
  bottom: 28px;
  transform: translateX(-50%);
  background: var(--ok);
  color: #fff;
  padding: 10px 18px;
  border-radius: 999px;
  font-size: 0.88rem;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.3);
  z-index: 9;
}

@media (max-width: 480px) {
  .card { padding: 18px 14px; }
  .field > span { flex-basis: 108px; font-size: 0.82rem; }
  textarea { height: 200px; }
}