:root {
  --bg: #f5f7fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --accent: #2563eb;
  --border: #d6deeb;
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  font-family: "Manrope", "Segoe UI", sans-serif;
  color: var(--text);
  background: radial-gradient(circle at top right, #e9f0ff 0%, var(--bg) 45%, #f9fbff 100%);
}

.app-header {
  padding: 1.2rem 1.5rem 0.4rem;
}

.app-header h1 {
  margin: 0;
  font-size: clamp(1.4rem, 2vw, 2rem);
  font-weight: 700;
  color: #111827;
}

.app-main {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
  padding: 1rem 1.5rem 1.5rem;
  min-height: calc(100vh - 76px);
}

.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 16px;
  box-shadow: 0 10px 25px rgba(17, 24, 39, 0.06);
  padding: 1rem;
}

.panel h2 {
  margin: 0 0 0.8rem;
  font-size: 1rem;
  font-weight: 700;
}

.teacher-setup {
  display: grid;
  gap: 0.38rem;
  margin-bottom: 1rem;
  padding: 0.8rem;
  border: 1px solid var(--border);
  border-radius: 12px;
  background: #fbfcff;
}

.teacher-setup label {
  font-size: 0.79rem;
  color: #475569;
  font-weight: 600;
}

.teacher-setup input {
  border: 1px solid #d4dfef;
  border-radius: 8px;
  padding: 0.5rem 0.56rem;
  font: 500 0.84rem "Manrope", sans-serif;
  color: #0f172a;
  background: #fff;
  margin-bottom: 0.32rem;
}

.teacher-setup input:focus {
  outline: 2px solid #d5e4ff;
  border-color: #90b4ff;
}

.teacher-setup input[readonly] {
  background: #f8fbff;
  color: #334155;
}

.generator-controls {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.45rem;
}

.generator-controls select,
.generator-controls input {
  width: 100%;
  border: 1px solid #d4dfef;
  border-radius: 8px;
  padding: 0.5rem 0.56rem;
  font: 500 0.84rem "Manrope", sans-serif;
  color: #0f172a;
  background: #fff;
}

#autoGenerateBtn {
  width: 100%;
  margin-bottom: 0.25rem;
}

.checkbox-row {
  display: flex;
  align-items: center;
  gap: 0.55rem;
  margin: 0.2rem 0 0.35rem;
  cursor: pointer;
}

.checkbox-row input {
  margin: 0;
  width: auto;
  transform: translateY(1px);
}

.standards-selector {
  border: 1px solid #d4dfef;
  border-radius: 10px;
  background: #ffffff;
  padding: 0.45rem;
  max-height: 360px;
  overflow: auto;
}

.standards-selector-hint {
  margin: 0;
  border: 1px dashed #cddbf5;
  border-radius: 10px;
  background: #f8fbff;
  color: #475569;
  padding: 0.7rem 0.8rem;
  font-size: 0.8rem;
}

.standards-quick-filters {
  display: grid;
  gap: 0.4rem;
  margin-bottom: 0.1rem;
}

.standards-filter-actions,
.standards-grade-pills {
  display: flex;
  flex-wrap: wrap;
  gap: 0.35rem;
}

.standards-filter-btn,
.standards-grade-pill {
  border: 1px solid #c8d7f3;
  border-radius: 999px;
  background: #ffffff;
  color: #1e293b;
  padding: 0.34rem 0.7rem;
  font: 600 0.75rem "Manrope", sans-serif;
  cursor: pointer;
}

.standards-filter-btn:hover,
.standards-grade-pill:hover {
  background: #eef4ff;
  border-color: #9eb8ec;
  transform: none;
}

.standards-grade-pill.active {
  background: #dbeafe;
  border-color: #7aa2ea;
  color: #1d4ed8;
}

.standards-group {
  border: 1px solid #e1e8f5;
  border-radius: 8px;
  padding: 0.36rem 0.42rem;
  margin-bottom: 0.36rem;
}

.standards-group.preferred-grade {
  border-color: #a8c3f5;
  background: #f8fbff;
}

.standards-group summary {
  cursor: pointer;
  font-size: 0.81rem;
  font-weight: 700;
  color: #1f2937;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 0.5rem;
}

.standards-group summary::after {
  content: attr(data-count);
  font-size: 0.7rem;
  font-weight: 700;
  color: #64748b;
  background: #eff5ff;
  border: 1px solid #d8e5fb;
  border-radius: 999px;
  padding: 0.08rem 0.45rem;
}

.standards-grid {
  margin-top: 0.36rem;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.2rem 0.55rem;
}

.standards-option {
  display: flex;
  align-items: flex-start;
  gap: 0.3rem;
  font-size: 0.75rem;
  color: #334155;
}

.standards-option input {
  margin: 0.12rem 0 0;
}

.standard-code {
  display: block;
  font-weight: 700;
  color: #1e293b;
}

.standard-desc {
  display: block;
  color: #475569;
  line-height: 1.25;
}

.selected-summary {
  margin: 0.15rem 0 0;
  font-size: 0.76rem;
  color: #334155;
}

.standards-import {
  border: 1px solid #d4dfef;
  border-radius: 8px;
  min-height: 78px;
  resize: vertical;
  padding: 0.45rem 0.56rem;
  font: 500 0.8rem/1.35 ui-monospace, "Cascadia Code", "Courier New", monospace;
}

.standards-actions {
  display: flex;
  gap: 0.4rem;
}

.standards-actions button {
  flex: 1;
  padding: 0.45rem 0.5rem;
  font-size: 0.77rem;
}

.editor-shell {
  display: flex;
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  height: min(58vh, 640px);
  background: #fbfcff;
}

.json-editor-section {
  margin-top: 0.2rem;
}

.json-editor-note {
  margin: 0 0 0.55rem;
  font-size: 0.8rem;
  color: #64748b;
}

.line-numbers {
  margin: 0;
  width: 54px;
  padding: 0.8rem 0.45rem;
  text-align: right;
  color: #94a3b8;
  background: #f1f5ff;
  border-right: 1px solid #dbe5f6;
  overflow: hidden;
  font: 500 0.85rem/1.5 ui-monospace, "Cascadia Code", "Courier New", monospace;
  user-select: none;
}

#jsonInput {
  width: calc(100% - 54px);
  border: none;
  resize: none;
  outline: none;
  padding: 0.8rem;
  font: 500 0.88rem/1.5 ui-monospace, "Cascadia Code", "Courier New", monospace;
  color: #111827;
  background: transparent;
  overflow: auto;
}

.status {
  margin: 0.7rem 0 0;
  font-size: 0.86rem;
  color: var(--muted);
}

.status.error {
  color: #b91c1c;
}

.button-row {
  margin-top: 0.9rem;
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 0.55rem;
}

button {
  border: 1px solid #b9cbf1;
  border-radius: 10px;
  background: linear-gradient(180deg, #ffffff 0%, #edf4ff 100%);
  color: #0f172a;
  padding: 0.65rem 0.6rem;
  font: 600 0.84rem "Manrope", sans-serif;
  cursor: pointer;
  transition: transform 0.12s ease, background 0.12s ease, border-color 0.12s ease;
}

button:hover {
  transform: translateY(-1px);
  border-color: #97b4ef;
  background: linear-gradient(180deg, #ffffff 0%, #dbe8ff 100%);
}

button:active {
  transform: translateY(0);
}

.preview-panel {
  overflow: auto;
}

.worksheet-preview {
  background: #ffffff;
  border: 1px solid #e3e8f2;
  border-radius: 12px;
  padding: 1.2rem;
  min-height: 64vh;
}

.preview-template {
  display: grid;
  gap: 1rem;
  align-content: start;
  min-height: 100%;
}

.preview-template-badge {
  display: inline-flex;
  width: fit-content;
  border-radius: 999px;
  background: #e0edff;
  color: #1d4ed8;
  padding: 0.3rem 0.7rem;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.02em;
}

.preview-template h3 {
  margin: 0;
  font-size: 1.45rem;
  color: #0f172a;
}

.preview-template p {
  margin: 0;
  max-width: 42rem;
  color: #475569;
  line-height: 1.6;
}

.preview-template-grid {
  display: grid;
  gap: 0.8rem;
  grid-template-columns: repeat(3, minmax(0, 1fr));
}

.preview-template-card {
  display: grid;
  gap: 0.35rem;
  border: 1px solid #d8e5fb;
  border-radius: 14px;
  background: linear-gradient(180deg, #fbfdff 0%, #f3f8ff 100%);
  padding: 0.95rem;
}

.preview-template-card strong {
  color: #0f172a;
  font-size: 0.9rem;
}

.preview-template-card span {
  color: #64748b;
  font-size: 0.82rem;
  line-height: 1.5;
}

.worksheet-sheet {
  max-width: 100%;
}

.ws-header h3 {
  margin: 0 0 0.6rem;
  font-size: 1.2rem;
}

.meta-row {
  margin-bottom: 0.8rem;
  display: flex;
  gap: 0.45rem;
  flex-wrap: wrap;
}

.meta-pill {
  font-size: 0.76rem;
  background: #eff5ff;
  color: #1e3a8a;
  border: 1px solid #cfddfa;
  padding: 0.22rem 0.48rem;
  border-radius: 999px;
}

.student-row {
  display: grid;
  grid-template-columns: 1fr auto 220px;
  gap: 1rem;
  margin-bottom: 1rem;
  font-size: 0.92rem;
}

.line {
  border-bottom: 1px solid #111827;
  display: inline-block;
  min-width: 100px;
  transform: translateY(-2px);
}

.problem-list {
  margin: 0;
  padding-left: 1.35rem;
}

.problem {
  margin-bottom: 1.3rem;
  break-inside: avoid;
  page-break-inside: avoid;
}

.problem-body {
  margin-bottom: 0.55rem;
  line-height: 1.45;
}

.problem-standard {
  margin: 0.1rem 0 0.48rem;
  font-size: 0.74rem;
  color: #1d4ed8;
}

.graph-wrap {
  margin: 0.4rem 0;
  padding: 0.55rem;
  border-radius: 10px;
  border: 1px solid #d8e0ef;
  display: inline-block;
  max-width: 100%;
  background: #fcfdff;
  break-inside: avoid;
  page-break-inside: avoid;
}

.graph-wrap svg {
  display: block;
  width: min(100%, 360px);
  height: auto;
}

.graph-caption {
  margin-top: 0.35rem;
  font-size: 0.76rem;
  color: #475569;
}

.workspace-lines div {
  border-bottom: 1px dashed #c6cfdd;
  height: 18px;
}

.answer-block {
  border-top: 2px solid #d3def5;
  margin-top: 1.2rem;
  padding-top: 0.9rem;
}

.desmos-link {
  display: inline-block;
  margin-top: 0.35rem;
  font-size: 0.82rem;
  color: var(--accent);
  text-decoration: none;
}

.desmos-link:hover {
  text-decoration: underline;
}

@media (max-width: 980px) {
  .app-main {
    grid-template-columns: 1fr;
  }

  .editor-shell {
    height: 42vh;
  }

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

  .generator-controls {
    grid-template-columns: 1fr;
  }

  .student-row {
    grid-template-columns: 1fr;
    gap: 0.5rem;
  }

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

  .graph-wrap {
    display: block;
  }
}

@media print {
  body {
    background: #ffffff;
  }

  .worksheet-preview {
    border: none;
    border-radius: 0;
    padding: 0;
    min-height: auto;
  }

  .problem,
  .graph-wrap,
  .workspace-lines,
  .answer-block {
    break-inside: avoid;
    page-break-inside: avoid;
  }
}