:root {
  --bg: #f4f2ec;
  --panel: #ffffff;
  --ink: #1f2933;
  --ink-soft: #52606d;
  --accent: #0f766e;
  --accent-soft: #d8f3ee;
  --warning: #b91c1c;
  --border: #d9d7cf;
  --shadow: 0 10px 24px rgba(20, 24, 28, 0.08);
  --radius: 12px;
  --font-main: "Source Sans 3", "Segoe UI", sans-serif;
  --font-mono: "JetBrains Mono", "Consolas", monospace;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: var(--font-main);
  color: var(--ink);
  background: radial-gradient(circle at top right, #efe5d3 0%, var(--bg) 40%, #f8f7f2 100%);
}

code {
  font-family: var(--font-mono);
}

.topbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.9rem 1.3rem;
  background: #1e293b;
  color: #f8fafc;
  border-bottom: 2px solid #0f172a;
}

.brand {
  font-size: 1.1rem;
  font-weight: 700;
}

.topbar-right {
  display: flex;
  align-items: center;
  gap: 0.7rem;
}

.language-switch {
  display: flex;
  gap: 0.35rem;
}

.lang-btn {
  border: 1px solid rgba(255, 255, 255, 0.35);
  background: rgba(255, 255, 255, 0.12);
  color: #f8fafc;
  border-radius: 999px;
  padding: 0.2rem 0.5rem;
  font-size: 0.76rem;
  font-weight: 700;
  cursor: pointer;
}

.lang-btn.active {
  background: #f8fafc;
  color: #0f172a;
  border-color: #f8fafc;
}

.user-chip {
  background: rgba(255, 255, 255, 0.12);
  padding: 0.35rem 0.65rem;
  border-radius: 999px;
  font-size: 0.9rem;
}

.page {
  padding: 1.2rem;
}

.card {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 1rem;
}

.layout-student,
.layout-teacher {
  display: grid;
  grid-template-columns: 300px minmax(0, 1fr);
  gap: 1rem;
}

.main-col {
  display: grid;
  gap: 1rem;
}

.sidebar {
  max-height: calc(100vh - 5.8rem);
  overflow: auto;
}

.student-list,
.exercise-list {
  display: grid;
  gap: 0.5rem;
}

.exercise-group-label {
  margin-top: 0.75rem;
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--ink-soft);
}

.exercise-item,
.student-item {
  width: 100%;
  border: 1px solid var(--border);
  background: #faf9f5;
  border-radius: 8px;
  padding: 0.6rem;
  text-align: left;
  cursor: pointer;
}

.exercise-item:hover,
.student-item:hover {
  border-color: var(--accent);
}

.exercise-item.active,
.student-item.active {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.exercise-title,
.student-name {
  font-weight: 700;
}

.exercise-title-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.45rem;
}

.exercise-status-chip {
  font-size: 0.75rem;
  padding: 0.08rem 0.4rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  background: #f8fafc;
  color: var(--ink-soft);
}

.exercise-status-chip.passed {
  background: #ecfdf5;
  color: #065f46;
  border-color: #a7f3d0;
}

.exercise-status-chip.failed {
  background: #fff1f2;
  color: #9f1239;
  border-color: #fecdd3;
}

.exercise-status-chip.needs_review {
  background: #fff7ed;
  color: #9a3412;
  border-color: #fed7aa;
}

.exercise-meta,
.muted {
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.card-header-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.8rem;
}

.grade-panel {
  margin-top: 0.55rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.4rem;
  align-items: center;
}

.grade-panel .pill {
  font-weight: 700;
}

.grade-status-passed {
  color: #065f46;
  background: #ecfdf5;
  border-color: #6ee7b7;
}

.grade-status-failed {
  color: #9f1239;
  background: #fff1f2;
  border-color: #fda4af;
}

.grade-status-needs_review {
  color: #9a3412;
  background: #fff7ed;
  border-color: #fdba74;
}

.grade-status-ungraded {
  color: #334155;
  background: #f8fafc;
  border-color: #cbd5e1;
}

.session-banner {
  margin-top: 0.6rem;
  margin-bottom: 0.6rem;
  border: 1px solid #8fd3c9;
  border-radius: 10px;
  background: #f0fdfa;
  padding: 0.6rem;
  display: grid;
  gap: 0.4rem;
}

.session-title-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.6rem;
}

.session-summary {
  margin-top: 0.55rem;
  margin-bottom: 0.55rem;
  color: var(--ink-soft);
  font-size: 0.88rem;
}

.inline-check {
  display: flex;
  align-items: center;
  gap: 0.45rem;
  min-width: 220px;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.45rem 0.55rem;
  color: var(--ink-soft);
}

.inline-check input {
  width: auto;
}

.pill {
  padding: 0.2rem 0.55rem;
  border-radius: 999px;
  border: 1px solid var(--border);
  color: var(--ink-soft);
  font-size: 0.8rem;
  white-space: nowrap;
}

textarea,
input,
select {
  width: 100%;
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.55rem 0.6rem;
  font-size: 0.95rem;
  font-family: var(--font-main);
}

textarea {
  font-family: var(--font-mono);
  resize: vertical;
  margin-top: 0.6rem;
}

.toolbar {
  margin-top: 0.7rem;
  display: flex;
  flex-wrap: wrap;
  gap: 0.55rem;
}

.toolbar-tight {
  margin-top: 0;
  gap: 0.4rem;
}

.toolbar-tight > * {
  flex: 0 0 auto;
  min-width: auto;
}

.toolbar > * {
  flex: 1;
  min-width: 140px;
}

.btn {
  background: var(--accent);
  color: #ffffff;
  border: 1px solid var(--accent);
  border-radius: 8px;
  padding: 0.55rem 0.7rem;
  font-weight: 600;
  cursor: pointer;
}

.btn:hover {
  filter: brightness(0.95);
}

.btn-outline {
  background: transparent;
  color: var(--accent);
}

.btn-small {
  padding: 0.35rem 0.5rem;
  font-size: 0.82rem;
  min-width: auto;
}

.exercise-item:disabled {
  opacity: 0.65;
  cursor: not-allowed;
  border-style: dashed;
}

.result-wrap {
  border: 1px dashed var(--border);
  border-radius: 8px;
  padding: 0.6rem;
  background: #fcfcfa;
  overflow: auto;
}

#schema-card.collapsed #schema-body {
  display: none;
}

#sandbox-browser-card.collapsed #sandbox-browser-body {
  display: none;
}

.result-step {
  margin-bottom: 0.9rem;
  border-bottom: 1px solid #ece8df;
  padding-bottom: 0.7rem;
}

.result-step:last-child {
  border-bottom: none;
  margin-bottom: 0;
}

.result-sql {
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: #334155;
  background: #f5f7f8;
  border-radius: 6px;
  padding: 0.4rem;
  white-space: pre-wrap;
}

.result-ok {
  color: #166534;
}

.result-error {
  color: var(--warning);
}

.table-wrap {
  overflow: auto;
}

.preview-table {
  min-width: 520px;
}

table {
  width: 100%;
  border-collapse: collapse;
  min-width: 720px;
}

th,
td {
  border-bottom: 1px solid #ece8df;
  text-align: left;
  padding: 0.45rem;
  font-size: 0.85rem;
  vertical-align: top;
}

th {
  background: #f6f8f9;
  font-size: 0.8rem;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: #516170;
}

.sql-cell {
  font-family: var(--font-mono);
  max-width: 480px;
  white-space: pre-wrap;
  word-break: break-word;
}

.alert {
  margin-top: 0.7rem;
  border-radius: 8px;
  padding: 0.55rem 0.65rem;
  border: 1px solid #9ca3af;
  background: #f3f4f6;
  color: #111827;
}

.alert.error {
  border-color: #f5c2c2;
  background: #fff1f1;
  color: #8a1c1c;
}

.alert.success {
  border-color: #a7f3d0;
  background: #ecfdf5;
  color: #065f46;
}

.hidden {
  display: none;
}

.form-grid {
  display: grid;
  gap: 0.7rem;
}

.form-grid.compact {
  gap: 0.45rem;
}

.login-wrap {
  min-height: calc(100vh - 5rem);
  display: grid;
  place-items: center;
  padding: 1rem;
}

.login-card {
  width: 100%;
  max-width: 420px;
}

.login-home-link {
  display: flex;
  justify-content: center;
  margin-top: 0.75rem;
  text-decoration: none;
}

.hint {
  margin-top: 0.7rem;
  font-size: 0.85rem;
  color: var(--ink-soft);
}

/* ── Teacher tab bar ── */
.teacher-tabs {
  display: flex;
  gap: 0.35rem;
  margin-bottom: 0.8rem;
}

.tab-btn {
  background: transparent;
  border: 1px solid var(--border);
  border-bottom: none;
  border-radius: 8px 8px 0 0;
  padding: 0.5rem 1rem;
  font-weight: 700;
  font-size: 0.92rem;
  cursor: pointer;
  color: var(--ink-soft);
  font-family: var(--font-main);
}

.tab-btn.active {
  background: var(--panel);
  color: var(--accent);
  border-color: var(--accent);
}

.tab-content {
  display: none;
}

.tab-content.active {
  display: grid;
}

/* ── Course-editor layout ── */
.layout-editor {
  grid-template-columns: 280px minmax(0, 1fr);
  gap: 1rem;
}

.editor-bilingual-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.6rem;
  align-items: start;
}

.editor-bilingual-row > .inline-check {
  grid-column: span 2;
  justify-self: start;
}

.mono-input {
  font-family: var(--font-mono) !important;
  font-size: 0.88rem;
}

/* ── Module cards ── */
.editor-module-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.7rem;
  margin-top: 0.55rem;
  background: #faf9f5;
}

.editor-module-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 0.5rem;
}

.editor-module-header h4 {
  margin: 0;
  font-size: 0.95rem;
}

.editor-module-actions {
  display: flex;
  gap: 0.3rem;
  align-items: center;
  flex-shrink: 0;
}

.editor-module-body {
  margin-top: 0.5rem;
}

.editor-module-form {
  display: grid;
  gap: 0.45rem;
  margin-bottom: 0.5rem;
}

.editor-module-exercises {
  display: grid;
  gap: 0.35rem;
  margin-top: 0.45rem;
}

.editor-module-exercise-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.35rem 0.5rem;
  background: var(--panel);
  font-size: 0.88rem;
}

.editor-module-exercise-item .exercise-title {
  font-weight: 600;
}

.editor-module-exercise-actions {
  display: flex;
  gap: 0.25rem;
}

/* Small icon-style buttons inside modules */
.btn-icon {
  background: transparent;
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 0.2rem 0.4rem;
  cursor: pointer;
  font-size: 0.8rem;
  line-height: 1;
  color: var(--ink-soft);
  font-family: var(--font-main);
}

.btn-icon:hover {
  border-color: var(--accent);
  color: var(--accent);
}

.btn-danger {
  color: var(--warning);
  border-color: var(--warning);
  background: transparent;
}

.btn-danger:hover {
  background: #fff1f1;
}

/* ── Add-exercise picker inside module ── */
.editor-add-ex-picker {
  display: flex;
  gap: 0.35rem;
  margin-top: 0.4rem;
}

.editor-add-ex-picker select {
  flex: 1;
  font-size: 0.85rem;
  padding: 0.3rem 0.4rem;
}

/* ── Editor sidebar toggle ── */
#editor-sidebar .toolbar-tight {
  margin-bottom: 0.5rem;
}

/* ── Responsive ── */
@media (max-width: 980px) {
  .layout-student,
  .layout-teacher,
  .layout-editor {
    grid-template-columns: 1fr;
  }

  .sidebar {
    max-height: none;
  }

  table {
    min-width: 620px;
  }

  .editor-bilingual-row {
    grid-template-columns: 1fr;
  }
}

/* Quiz Question Styles */
.quiz-question-form {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 16px;
  margin: 12px 0;
}

.quiz-question-form h4 {
  margin: 0 0 12px;
  font-size: 14px;
  color: var(--ink-soft);
}

.quiz-question-form .form-row {
  margin-bottom: 12px;
}

.quiz-question-form .form-row label {
  display: block;
  font-size: 12px;
  color: var(--ink-soft);
  margin-bottom: 4px;
}

.quiz-question-form textarea,
.quiz-question-form input[type="text"],
.quiz-question-form select {
  width: 100%;
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 13px;
  background: #ffffff;
  color: #111111;
}

.quiz-question-form fieldset {
  border: 1px solid var(--border);
  border-radius: 4px;
  padding: 12px;
  margin: 12px 0;
}

.quiz-question-form fieldset legend {
  font-size: 12px;
  color: var(--ink-soft);
  padding: 0 4px;
}

.quiz-option-row {
  display: grid;
  grid-template-columns: 24px minmax(180px, 1fr) minmax(180px, 1fr);
  align-items: center;
  column-gap: 8px;
  row-gap: 6px;
  margin-bottom: 8px;
}

.quiz-option-row input[type="radio"] {
  flex-shrink: 0;
}

.quiz-option-row input[type="text"] {
  width: 100%;
  min-width: 0;
  padding: 6px 8px;
  border: 1px solid var(--border);
  border-radius: 4px;
  font-size: 12px;
  background: #ffffff;
  color: #111111 !important;
  -webkit-text-fill-color: #111111 !important;
  opacity: 1 !important;
  caret-color: #111111;
}

.form-actions {
  display: flex;
  gap: 8px;
  margin-top: 12px;
}

.quiz-question-item {
  background: var(--panel);
  border: 1px solid var(--border);
  border-radius: 6px;
  padding: 12px;
  margin-bottom: 8px;
}

.quiz-q-header {
  display: flex;
  align-items: center;
  gap: 8px;
}

.quiz-q-number {
  font-weight: bold;
  color: var(--accent);
}

.quiz-q-text {
  flex: 1;
  font-size: 13px;
}

.quiz-q-diff {
  font-size: 11px;
  padding: 2px 6px;
  background: #f1f5f9;
  border-radius: 4px;
  color: var(--ink-soft);
}

.quiz-q-actions {
  display: flex;
  gap: 6px;
  margin-top: 8px;
}

.quiz-q-meta {
  margin-top: 6px;
  font-size: 12px;
  color: var(--ink-soft);
}

.empty-state {
  color: var(--ink-soft);
  font-size: 13px;
  font-style: italic;
  padding: 16px;
  text-align: center;
}

/* Student quiz navigation + dedicated page */
.quiz-nav-item .exercise-title {
  font-weight: 700;
}

#student-quiz-page {
  display: grid;
  gap: 0.9rem;
}

.quiz-progress {
  display: grid;
  gap: 0.4rem;
}

.progress-bar {
  height: 8px;
  border-radius: 999px;
  background: #e2e8f0;
  overflow: hidden;
}

.progress-fill {
  height: 100%;
  background: var(--accent);
  transition: width 0.25s ease;
}

.quiz-question h3 {
  margin: 0 0 0.7rem;
}

.quiz-options {
  display: grid;
  gap: 0.5rem;
}

.quiz-option-btn {
  width: 100%;
  display: grid;
  grid-template-columns: 28px 1fr;
  gap: 0.55rem;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: 8px;
  background: #ffffff;
  color: var(--ink);
  padding: 0.55rem 0.65rem;
  text-align: left;
  cursor: pointer;
}

.quiz-option-btn:hover {
  border-color: var(--accent);
}

.quiz-option-btn:disabled {
  opacity: 0.75;
  cursor: default;
}

.option-letter {
  display: grid;
  place-items: center;
  width: 24px;
  height: 24px;
  border-radius: 999px;
  background: #f1f5f9;
  font-weight: 700;
  color: #334155;
}

.quiz-feedback {
  margin-top: 0.8rem;
  display: grid;
  gap: 0.6rem;
}

.feedback-content {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.55rem 0.65rem;
}

.feedback-content.correct {
  border-color: #86efac;
  background: #f0fdf4;
}

.feedback-content.incorrect {
  border-color: #fda4af;
  background: #fff1f2;
}

.quiz-result {
  display: grid;
  gap: 0.5rem;
  justify-items: start;
}

.score-display .score-number {
  font-size: 2rem;
  font-weight: 800;
  color: var(--accent);
}

.certificates-list {
  display: grid;
  gap: 0.55rem;
}

.certificate-card {
  border: 1px solid var(--border);
  border-radius: 8px;
  padding: 0.55rem 0.65rem;
  background: #faf9f5;
}

.certificate-card h4 {
  margin: 0 0 0.25rem;
}

.landing-page {
  display: grid;
  gap: 1.1rem;
}

.landing-hero {
  display: grid;
  grid-template-columns: 1.1fr 1fr;
  gap: 1.2rem;
  align-items: center;
  background: linear-gradient(135deg, #f3fbf9, #f2f2ff);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.4rem;
}

.landing-kicker {
  letter-spacing: 0.08em;
  text-transform: uppercase;
  font-size: 0.76rem;
  color: #0f766e;
  margin-bottom: 0.4rem;
  font-weight: 700;
}

.landing-hero h1 {
  margin: 0;
  font-size: 2rem;
  line-height: 1.15;
}

.landing-hero p {
  color: var(--ink-soft);
  max-width: 58ch;
}

.landing-actions {
  display: flex;
  gap: 0.6rem;
  margin-top: 0.7rem;
}

.landing-hero-art svg {
  width: 100%;
  height: auto;
  border-radius: 12px;
  box-shadow: var(--shadow);
}

.landing-grid {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 0.9rem;
}

.landing-card {
  background: #ffffff;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 1rem;
}

.landing-card h3 {
  margin: 0 0 0.45rem;
}

.landing-card p {
  margin: 0;
  color: var(--ink-soft);
}

@media (max-width: 980px) {
  .landing-hero {
    grid-template-columns: 1fr;
    padding: 1rem;
  }

  .landing-hero h1 {
    font-size: 1.6rem;
  }

  .landing-grid {
    grid-template-columns: 1fr;
  }
}