/* =========================
   Base / Variables
========================= */

:root {
  --bg1: #d8eaff;
  --bg2: #b0d6f0;
  --primary: #007bff;
  --primary-dark: #0056b3;
  --accent: #17a2b8;
  --accent-dark: #117a8b;
  --ok: #28a745;
  --bad: #dc3545;
  --text: #333;
  --card: #ffffff;
  --border: #cfcfcf;

  --shadow: 0 10px 26px rgba(0, 0, 0, 0.12);
  --shadow-strong: 0 22px 60px rgba(0, 0, 0, 0.25);
  --radius: 12px;
}

* {
  box-sizing: border-box;
}

body {
  font-family: "Poppins", Arial, sans-serif;
  background: linear-gradient(135deg, var(--bg1), var(--bg2));
  padding: 20px;
  margin: 0;
  color: var(--text);
}

.credits-top {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 8px;
  margin: 0 auto 18px;
  color: #34506c;
  font-size: 0.95rem;
  font-weight: 700;
}

.credits-top a {
  color: var(--primary);
  text-decoration: none;
}

.credits-top a:hover {
  text-decoration: underline;
}

.credits-separator {
  opacity: 0.55;
}

/* Hide elements using HTML hidden */
[hidden] {
  display: none !important;
}

/* =========================
   Header
========================= */

.page-header {
  text-align: center;
  margin-bottom: 14px;
}

.page-header h1 {
  font-size: 2.5rem;
  color: #1d4ed8;
  margin: 0 0 10px 0;
}

.page-header p {
  font-size: 1.2rem;
  margin: 0;
}

/* =========================
   Language bar
========================= */

.language-bar {
  text-align: center;
  margin-bottom: 18px;
}

.language-bar label {
  font-size: 1.15rem;
  margin-right: 8px;
  font-weight: 600;
}

.language-bar select {
  font-size: 1.1rem;
  padding: 10px 12px;
  border: 2px solid var(--primary);
  border-radius: 10px;
  background-color: var(--card);
  box-shadow: 0 2px 0 rgba(0,0,0,0.06);
}

/* =========================
   Meta bar
========================= */

.meta-bar {
  width: 80%;
  max-width: 520px;
  margin: 0 auto 10px auto;
  text-align: center;
  font-size: 0.95rem;
  opacity: 0.85;
}

/* =========================
   Question cards
========================= */

#questions-container {
  margin-top: 10px;
}

.question-container {
  margin: 16px auto;
  padding: 18px;
  width: 80%;
  max-width: 520px;
  background-color: var(--card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  transition: transform 0.2s, box-shadow 0.2s;
}

.question-container:hover {
  transform: translateY(-1px);
  box-shadow: 0 14px 32px rgba(0,0,0,0.14);
}

/* =========================
   Answer buttons
========================= */

.choice-btn {
  width: 100%;
  padding: 14px 14px;
  margin: 10px 0;
  background-color: var(--primary);
  color: white;
  font-size: 1.06rem;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: background-color 0.2s, box-shadow 0.2s, transform 0.05s;
}

.choice-btn:hover {
  background-color: var(--primary-dark);
  box-shadow: 0 8px 14px rgba(0,0,0,0.18);
}

.choice-btn:active {
  transform: translateY(1px);
}

.choice-btn:disabled {
  cursor: not-allowed;
  background-color: #d3d3d3;
  color: #333;
  box-shadow: none;
}

.choice-btn.selected {
  outline: 3px solid #1d4ed8;
  outline-offset: 2px;
}

/* =========================
   Hint area
========================= */

.hint-section {
  margin-top: 10px;
  display: flex;
  align-items: center;
  gap: 10px;
  flex-wrap: wrap;
}

.hint-btn {
  padding: 10px 16px;
  font-size: 1rem;
  background-color: var(--accent);
  color: white;
  border: none;
  border-radius: 10px;
  cursor: pointer;
  transition: background-color 0.2s, box-shadow 0.2s;
}

.hint-btn:hover {
  background-color: var(--accent-dark);
  box-shadow: 0 6px 12px rgba(0,0,0,0.14);
}

.hint-btn:disabled {
  background-color: #d3d3d3;
  color: #777;
  cursor: not-allowed;
  box-shadow: none;
}

/* clickable grammar link */
.case-link {
  color: #1d4ed8;
  font-weight: 700;
  text-decoration: underline;
  text-underline-offset: 3px;
}

.case-link:hover {
  text-decoration: none;
}

/* =========================
   Feedback
========================= */

.feedback {
  margin-top: 10px;
  font-size: 1.02rem;
  font-weight: 650;
  line-height: 1.35;
}

.correct {
  color: var(--ok);
}

.incorrect {
  color: var(--bad);
}

/* =========================
   Score section
========================= */

.score,
#score-display {
  background-color: var(--card);
  padding: 20px;
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  width: 80%;
  max-width: 520px;
  margin: 26px auto;
  text-align: center;
}

#score-display h2 {
  margin: 0 0 8px 0;
}

/* =========================
   Try again button
========================= */

.try-again-btn {
  padding: 12px 22px;
  font-size: 1.15rem;
  background-color: var(--primary);
  color: white;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  display: block;
  margin: 0 auto 14px;
  transition: background-color 0.2s, box-shadow 0.2s, transform 0.05s;
}

.try-again-btn:hover {
  background-color: var(--primary-dark);
  box-shadow: 0 10px 18px rgba(0,0,0,0.18);
}

.try-again-btn:active {
  transform: translateY(1px);
}

.try-again-btn.visible {
  display: block;
}

/* =========================
   Modal – Grammar rules
========================= */

.modal[aria-hidden="true"] {
  display: none;
}

.modal {
  position: fixed;
  inset: 0;
  z-index: 9999;
}

.modal__backdrop {
  position: absolute;
  inset: 0;
  background: rgba(0,0,0,0.45);
  backdrop-filter: blur(3px);
}

.modal__card {
  position: relative;
  width: min(760px, calc(100% - 32px));
  margin: 8vh auto;
  background: var(--card);
  border-radius: 16px;
  box-shadow: var(--shadow-strong);
  border: 1px solid rgba(0,0,0,0.1);
  overflow: hidden;
}

.modal__header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 14px 18px;
  background: linear-gradient(135deg, var(--bg1), var(--bg2));
  border-bottom: 1px solid rgba(0,0,0,0.08);
}

.modal__title {
  margin: 0;
  font-size: 1.25rem;
  color: #1d4ed8;
  font-weight: 800;
}

.modal__close {
  border: none;
  background: rgba(255,255,255,0.4);
  font-size: 1.25rem;
  cursor: pointer;
  padding: 6px 10px;
  border-radius: 10px;
}

.modal__close:hover {
  background: rgba(255,255,255,0.7);
}

.modal__body {
  padding: 18px;
  max-height: 60vh;
  overflow: auto;
  color: var(--text);
}

.modal__footer {
  padding: 14px 18px 18px;
  display: flex;
  justify-content: flex-end;
}

.modal__ok {
  padding: 10px 18px;
  font-size: 1rem;
  background-color: var(--primary);
  color: white;
  border: none;
  border-radius: 12px;
  cursor: pointer;
  transition: background-color 0.2s, box-shadow 0.2s;
}

.modal__ok:hover {
  background-color: var(--primary-dark);
  box-shadow: 0 10px 18px rgba(0,0,0,0.16);
}

/* Tables inside modal */
.modal__body table {
  width: 100%;
  border-collapse: collapse;
  margin-top: 12px;
  font-size: 0.95rem;
}

.modal__body th,
.modal__body td {
  border: 1px solid rgba(0,0,0,0.12);
  padding: 9px 8px;
  text-align: center;
}

.modal__body th {
  background: #f3f7ff;
  font-weight: 800;
}

/* =========================
   Mobile
========================= */

@media screen and (max-width: 768px) {
  .page-header h1 {
    font-size: 2rem;
  }

  .page-header p {
    font-size: 1.05rem;
  }

  .question-container {
    width: 92%;
    padding: 16px;
  }

  .choice-btn {
    font-size: 1rem;
    padding: 12px;
  }

  .language-bar select {
    font-size: 1.05rem;
  }

  .modal__card {
    margin: 6vh auto;
  }
}