:root {
  --vin-blue: #0b2f6b;
  --vin-blue-dark: #071d47;
  --vin-blue-light: #1a4fa0;
  --vin-red: #d21f3c;
  --vin-gold: #f2b705;
  --bg: #f4f6fb;
  --card-bg: #ffffff;
  --text: #1c2438;
  --text-muted: #62697c;
  --border: #e2e6f0;
  --green: #1f9d55;
  --green-bg: #e8f8ee;
  --red-bg: #fdecee;
  --radius: 14px;
  --shadow: 0 4px 18px rgba(11, 47, 107, 0.08);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  background: linear-gradient(180deg, #eef2fb 0%, #f4f6fb 320px, #f4f6fb 100%);
  color: var(--text);
  min-height: 100vh;
}

.app {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px 18px 60px;
}

header.app-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 22px;
}

.logo-badge {
  width: 46px;
  height: 46px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--vin-blue), var(--vin-blue-light));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 20px;
  flex-shrink: 0;
  box-shadow: var(--shadow);
}

.app-header-title {
  flex: 1;
  min-width: 0;
}

#logout-btn {
  flex-shrink: 0;
  white-space: nowrap;
}

header.app-header h1 {
  font-size: 20px;
  margin: 0;
  color: var(--vin-blue-dark);
}

header.app-header p {
  margin: 2px 0 0;
  font-size: 13px;
  color: var(--text-muted);
}

.user-area {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

.user-greeting {
  font-size: 13px;
  font-weight: 600;
  color: var(--vin-blue-dark);
  max-width: 160px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.btn-sm {
  padding: 7px 12px;
  font-size: 13px;
}

/* Auth screen */
.auth-card {
  max-width: 420px;
  margin: 24px auto 0;
}

.auth-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 18px;
  border-bottom: 1px solid var(--border);
}

.auth-tab {
  flex: 1;
  border: none;
  background: none;
  padding: 10px 8px 12px;
  font-size: 15px;
  font-weight: 700;
  color: var(--text-muted);
  cursor: pointer;
  border-bottom: 3px solid transparent;
  margin-bottom: -1px;
}

.auth-tab.active {
  color: var(--vin-blue);
  border-bottom-color: var(--vin-blue);
}

.auth-form {
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.auth-form input {
  width: 100%;
  padding: 11px 12px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 14.5px;
}

.auth-form input:focus {
  outline: none;
  border-color: var(--vin-blue-light);
  box-shadow: 0 0 0 2px rgba(11, 47, 107, 0.12);
}

.auth-error {
  font-size: 13px;
  color: var(--vin-red);
  min-height: 4px;
  line-height: 1.4;
}

.auth-note {
  margin-top: 16px;
  font-size: 12px;
  color: var(--text-muted);
  line-height: 1.5;
  text-align: center;
}

.card {
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 22px;
  margin-bottom: 18px;
  border: 1px solid var(--border);
}

.section-title {
  font-size: 15px;
  font-weight: 700;
  color: var(--vin-blue-dark);
  margin: 0 0 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.module-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 8px;
}

.module-option {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  cursor: pointer;
  transition: border-color .15s, background .15s;
  font-size: 13.5px;
  line-height: 1.4;
}

.module-option:hover {
  border-color: var(--vin-blue-light);
  background: #f7faff;
}

.module-option input {
  margin-top: 3px;
  accent-color: var(--vin-blue);
  flex-shrink: 0;
}

.module-option .count {
  color: var(--text-muted);
  font-size: 12px;
  white-space: nowrap;
  margin-left: auto;
  padding-left: 8px;
}

.exam-option {
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  gap: 4px;
  width: 100%;
  background: #fff;
  text-align: left;
  font-family: inherit;
}

.exam-option strong {
  color: var(--vin-blue-dark);
  font-size: 14.5px;
}

.exam-option span {
  color: var(--text-muted);
  font-size: 12.5px;
}

.select-all-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.select-all-row button {
  border: none;
  background: none;
  color: var(--vin-blue-light);
  font-size: 13px;
  cursor: pointer;
  text-decoration: underline;
  padding: 0;
}

.row {
  display: flex;
  gap: 16px;
  flex-wrap: wrap;
}

.field {
  flex: 1;
  min-width: 200px;
}

.field label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--vin-blue-dark);
  margin-bottom: 6px;
}

.field input[type="number"] {
  width: 100%;
  padding: 9px 10px;
  border-radius: 8px;
  border: 1px solid var(--border);
  font-size: 14px;
}

.mode-toggle {
  display: flex;
  gap: 10px;
}

.mode-option {
  flex: 1;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  padding: 12px;
  cursor: pointer;
  text-align: center;
  transition: all .15s;
}

.mode-option.active {
  border-color: var(--vin-blue);
  background: #eef4ff;
  box-shadow: 0 0 0 2px rgba(11, 47, 107, 0.12) inset;
}

.mode-option strong {
  display: block;
  font-size: 14px;
  color: var(--vin-blue-dark);
  margin-bottom: 3px;
}

.mode-option span {
  font-size: 12px;
  color: var(--text-muted);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: none;
  border-radius: 10px;
  padding: 12px 20px;
  font-size: 14.5px;
  font-weight: 600;
  cursor: pointer;
  transition: transform .1s, box-shadow .15s, opacity .15s;
}

.btn:active {
  transform: scale(0.98);
}

.btn-primary {
  background: linear-gradient(135deg, var(--vin-blue), var(--vin-blue-light));
  color: #fff;
  box-shadow: 0 6px 16px rgba(11, 47, 107, 0.25);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  box-shadow: none;
}

.btn-secondary {
  background: #fff;
  color: var(--vin-blue-dark);
  border: 1.5px solid var(--border);
}

.btn-danger {
  background: var(--vin-red);
  color: #fff;
}

.btn-block {
  width: 100%;
}

.start-btn-wrap {
  margin-top: 8px;
}

.hint {
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 6px;
}

/* Quiz screen */
.quiz-topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 14px;
  flex-wrap: wrap;
  gap: 10px;
}

.progress-text {
  font-weight: 600;
  color: var(--vin-blue-dark);
  font-size: 14px;
}

.timer-badge {
  background: var(--vin-blue-dark);
  color: #fff;
  padding: 6px 14px;
  border-radius: 20px;
  font-weight: 700;
  font-size: 13px;
  letter-spacing: 0.5px;
}

.timer-badge.warning {
  background: var(--vin-red);
}

.progress-bar {
  height: 7px;
  border-radius: 6px;
  background: var(--border);
  overflow: hidden;
  margin-bottom: 18px;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--vin-blue), var(--vin-gold));
  transition: width .25s;
}

.module-tag {
  display: inline-block;
  font-size: 11.5px;
  font-weight: 700;
  color: var(--vin-blue);
  background: #eaf1ff;
  padding: 3px 10px;
  border-radius: 20px;
  margin-bottom: 10px;
}

.type-badge {
  display: inline-block;
  font-size: 11.5px;
  font-weight: 700;
  color: #8a5a00;
  background: #fff4d9;
  padding: 3px 10px;
  border-radius: 20px;
  margin-bottom: 10px;
  margin-left: 8px;
}

.question-text {
  font-size: 17px;
  font-weight: 600;
  line-height: 1.5;
  margin: 0 0 18px;
  color: var(--text);
}

.options-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.option-btn {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  text-align: left;
  padding: 13px 14px;
  border: 1.5px solid var(--border);
  border-radius: 10px;
  background: #fff;
  cursor: pointer;
  font-size: 14.5px;
  line-height: 1.45;
  transition: border-color .12s, background .12s;
}

.option-btn:hover:not(.disabled) {
  border-color: var(--vin-blue-light);
  background: #f7faff;
}

.option-letter {
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: 1.5px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12.5px;
  font-weight: 700;
  color: var(--text-muted);
}

.option-btn.msq .option-letter {
  border-radius: 6px;
  font-size: 15px;
}

.option-btn.selected {
  border-color: var(--vin-blue);
  background: #eef4ff;
}

.option-btn.selected .option-letter {
  background: var(--vin-blue);
  border-color: var(--vin-blue);
  color: #fff;
}

.option-btn.correct {
  border-color: var(--green);
  background: var(--green-bg);
}

.option-btn.correct .option-letter {
  background: var(--green);
  border-color: var(--green);
  color: #fff;
}

.option-btn.incorrect {
  border-color: var(--vin-red);
  background: var(--red-bg);
}

.option-btn.incorrect .option-letter {
  background: var(--vin-red);
  border-color: var(--vin-red);
  color: #fff;
}

.option-btn.disabled {
  cursor: default;
}

.explanation-box {
  margin-top: 16px;
  padding: 14px;
  border-radius: 10px;
  background: #fbf8ee;
  border: 1px solid #f0e2b0;
  font-size: 13.5px;
  line-height: 1.55;
  color: #5c4a12;
}

.explanation-box strong {
  color: var(--vin-blue-dark);
}

.quiz-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 20px;
  gap: 10px;
  flex-wrap: wrap;
}

.quiz-nav .side-group {
  display: flex;
  gap: 10px;
}

.qnav-dots {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 16px;
}

.qnav-dot {
  width: 30px;
  height: 30px;
  border-radius: 8px;
  border: 1.5px solid var(--border);
  background: #fff;
  font-size: 12px;
  font-weight: 700;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
}

.qnav-dot.current {
  border-color: var(--vin-blue);
  box-shadow: 0 0 0 2px rgba(11, 47, 107, 0.15);
}

.qnav-dot.answered {
  background: #eaf1ff;
  color: var(--vin-blue);
  border-color: var(--vin-blue-light);
}

/* Flashcard screen */
.fc-known-count {
  background: var(--green-bg);
  color: var(--green);
  padding: 6px 14px;
  border-radius: 20px;
  font-weight: 700;
  font-size: 13px;
}

.flashcard {
  perspective: 1600px;
  cursor: pointer;
  margin-bottom: 18px;
  min-height: 340px;
}

.flashcard-inner {
  position: relative;
  width: 100%;
  min-height: 340px;
  transition: transform 0.5s;
  transform-style: preserve-3d;
}

.flashcard-inner.flipped {
  transform: rotateY(180deg);
}

.flashcard-face {
  position: absolute;
  inset: 0;
  -webkit-backface-visibility: hidden;
  backface-visibility: hidden;
  background: var(--card-bg);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
  padding: 22px;
  display: flex;
  flex-direction: column;
}

.flashcard-front {
  border-top: 4px solid var(--vin-blue);
}

.flashcard-back {
  transform: rotateY(180deg);
  border-top: 4px solid var(--green);
  background: #f6fbf7;
}

.fc-hint-top {
  font-size: 11px;
  font-weight: 700;
  letter-spacing: 0.6px;
  color: var(--text-muted);
  margin-bottom: 8px;
  text-transform: uppercase;
}

.fc-question {
  font-size: 17px;
  font-weight: 600;
  line-height: 1.5;
  margin: 4px 0 14px;
  color: var(--text);
}

.fc-options {
  display: flex;
  flex-direction: column;
  gap: 6px;
  margin-bottom: auto;
}

.fc-option-row {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 13.5px;
  line-height: 1.45;
  color: var(--text-muted);
  padding: 4px 0;
}

.fc-opt-letter {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  border: 1.5px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 11.5px;
  font-weight: 700;
}

.fc-answer {
  font-size: 18px;
  font-weight: 700;
  line-height: 1.5;
  color: var(--green);
  margin: 4px 0 14px;
}

.fc-explain {
  font-size: 14px;
  line-height: 1.6;
  color: var(--text);
  background: #fff;
  border: 1px solid #d7ecdd;
  border-radius: 10px;
  padding: 12px 14px;
  margin-bottom: auto;
}

.fc-flip-hint {
  text-align: center;
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 16px;
  font-style: italic;
}

/* Result screen */
.result-hero {
  text-align: center;
  padding: 10px 0 4px;
}

.result-score {
  font-size: 46px;
  font-weight: 800;
  color: var(--vin-blue-dark);
  margin: 6px 0 0;
}

.result-score span {
  font-size: 20px;
  color: var(--text-muted);
  font-weight: 600;
}

.result-percent {
  display: inline-block;
  margin-top: 10px;
  padding: 5px 16px;
  border-radius: 20px;
  font-weight: 700;
  font-size: 13px;
}

.result-percent.pass {
  background: var(--green-bg);
  color: var(--green);
}

.result-percent.fail {
  background: var(--red-bg);
  color: var(--vin-red);
}

.module-breakdown {
  margin-top: 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.module-breakdown-row {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 13px;
}

.module-breakdown-row .name {
  flex: 1;
  color: var(--text);
}

.mini-bar {
  flex: 2;
  height: 8px;
  background: var(--border);
  border-radius: 5px;
  overflow: hidden;
}

.mini-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--vin-blue), var(--vin-gold));
}

.module-breakdown-row .score {
  width: 46px;
  text-align: right;
  color: var(--text-muted);
  font-weight: 600;
}

.result-actions {
  display: flex;
  gap: 10px;
  margin-top: 8px;
  flex-wrap: wrap;
}

.review-item {
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 16px;
  margin-bottom: 12px;
}

.review-item.wrong {
  border-left: 4px solid var(--vin-red);
}

.review-item.right {
  border-left: 4px solid var(--green);
}

.review-q {
  font-weight: 600;
  margin-bottom: 8px;
  font-size: 14.5px;
}

.review-answer-line {
  font-size: 13.5px;
  margin: 3px 0;
}

.review-answer-line.your-wrong {
  color: var(--vin-red);
}

.review-answer-line.your-right {
  color: var(--green);
}

.review-answer-line.correct-line {
  color: var(--green);
}

.review-explain {
  margin-top: 8px;
  font-size: 13px;
  color: var(--text-muted);
  background: #f7f8fb;
  border-radius: 8px;
  padding: 10px 12px;
}

.history-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 12.5px;
}

.history-table th, .history-table td {
  text-align: left;
  padding: 7px 8px;
  border-bottom: 1px solid var(--border);
  color: var(--text-muted);
}

.history-table th {
  color: var(--vin-blue-dark);
  font-weight: 700;
}

.empty-history {
  font-size: 13px;
  color: var(--text-muted);
  text-align: center;
  padding: 10px 0;
}

.history-view-btn {
  padding: 4px 10px;
  font-size: 12px;
}

.hidden {
  display: none !important;
}

footer.app-footer {
  text-align: center;
  font-size: 12px;
  color: var(--text-muted);
  margin-top: 24px;
}

@media (min-width: 640px) {
  .module-grid {
    grid-template-columns: 1fr 1fr;
  }
}