.trig-lead {
  font-size: 1.08rem;
  line-height: 1.75;
  color: var(--muted);
}

.card,
.concept,
.identity-card {
  transition:
    transform 0.25s ease,
    box-shadow 0.25s ease,
    border-color 0.25s ease;
}

.card:hover,
.concept:hover,
.identity-card:hover {
  transform: translateY(-3px);
  border-color: rgba(15, 118, 110, 0.28);
}

.page-hero {
  animation: rise-in 0.55s ease both;
}

.trig-nav {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  margin: 15px 0 26px;
}

.trig-nav a {
  padding: 9px 13px;
  border: 1px solid var(--line);
  border-radius: 999px;
  color: var(--text);
  text-decoration: none;
  font-size: 0.9rem;
}

.trig-nav a:hover,
.trig-nav a.active {
  border-color: var(--accent);
  color: var(--accent);
}

.concept-grid,
.graph-grid,
.identity-grid,
.angle-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.concept {
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.025);
}

.concept h4 {
  margin: 0 0 8px;
}

.concept p {
  margin: 0;
  color: var(--muted);
  line-height: 1.65;
}

.visual-card {
  overflow: hidden;
}

.diagram {
  display: block;
  width: 100%;
  height: auto;
  min-height: 280px;
  border-radius: 18px;
  background: #09131f;
}

.diagram text {
  font-family: "IBM Plex Sans", sans-serif;
}

.diagram .shape {
  fill: rgba(81, 196, 255, 0.08);
  stroke: #62d5ff;
  stroke-width: 3;
}

.diagram .accent-line {
  stroke: #ffca63;
  stroke-width: 5;
}

.diagram .hot-line {
  stroke: #ff7a9d;
  stroke-width: 5;
}

.diagram .guide {
  stroke: #75859c;
  stroke-width: 2;
  stroke-dasharray: 7 7;
}

.diagram .label {
  fill: #e9f2ff;
  font-size: 17px;
  font-weight: 600;
}
.diagram .opposite-label {
  fill: #ff7a9d;
}

.diagram .small-label {
  fill: #aab8cb;
  font-size: 14px;
}

.observer-box {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-top: 18px;
}

.observer-box > div {
  padding: 16px;
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.035);
}

.observer-box strong {
  display: block;
  margin-bottom: 6px;
}

.opposite {
  color: #ff7a9d;
}

.adjacent {
  color: #ffca63;
}

.formula-strip {
  padding: 18px;
  border-left: 4px solid var(--accent);
  background: rgba(87, 197, 255, 0.07);
  font-size: 1.05rem;
}

.graph-card {
  padding: 18px;
}

.graph-card h3 {
  margin: 0 0 4px;
}

.graph-card p {
  min-height: 42px;
  color: var(--muted);
  font-size: 0.92rem;
}

.trig-graph {
  display: block;
  width: 100%;
  height: 230px;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: #08111c;
}

.function-table td:first-child {
  font-weight: 700;
  color: var(--accent);
}

.angle-wheel {
  display: block;
  width: min(520px, 100%);
  margin: auto;
}

.comparison {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

.comparison > div {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
}

.comparison strong {
  display: block;
  color: var(--accent);
  margin-bottom: 6px;
}

.identity-card {
  padding: 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.025);
}

.identity-card h4 {
  margin: 0 0 8px;
  color: var(--accent);
}

.identity-card p {
  color: var(--muted);
  line-height: 1.6;
}

.identity-origin {
  display: grid;
  grid-template-columns: minmax(280px, 0.8fr) 1.2fr;
  gap: 24px;
  align-items: center;
}

.mini-note {
  font-size: 0.9rem;
  color: var(--muted);
}

.lab-grid {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(280px, 0.75fr);
  gap: 22px;
  align-items: start;
}

.lab-canvas {
  display: block;
  width: 100%;
  height: 430px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #08131f;
}

.control-panel {
  display: grid;
  gap: 18px;
}

.slider-control label {
  display: flex;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 8px;
  font-weight: 600;
}

.slider-control output {
  color: var(--primary);
  font-variant-numeric: tabular-nums;
}

.slider-control input[type="range"] {
  width: 100%;
  accent-color: var(--primary);
}

.live-values {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 10px;
}

.live-value {
  padding: 13px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(255, 255, 255, 0.4);
}

.live-value span {
  display: block;
  margin-bottom: 4px;
  color: var(--muted);
  font-size: 0.78rem;
}

.live-value strong {
  color: var(--primary);
  font-size: 1.05rem;
  font-variant-numeric: tabular-nums;
}

.lab-explanation {
  padding: 16px;
  border-left: 4px solid var(--accent);
  border-radius: 8px;
  background: rgba(231, 111, 81, 0.08);
  line-height: 1.65;
}

.projection-legend {
  display: grid;
  gap: 8px;
  font-size: 0.86rem;
}

.projection-legend span {
  display: flex;
  align-items: center;
  gap: 9px;
}

.projection-legend span::before {
  width: 22px;
  height: 4px;
  border-radius: 999px;
  content: "";
}

.projection-legend .legend-x::before {
  background: #ffca63;
}

.projection-legend .legend-y::before {
  background: #ff7a9d;
}

.projection-legend .legend-tan::before {
  background: #8bf0cb;
}

.projection-legend .legend-ray::before {
  height: 2px;
  background: repeating-linear-gradient(
    90deg,
    #94a8bd 0 5px,
    transparent 5px 9px
  );
}

.sync-graphs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 18px;
}

.sync-graph {
  width: 100%;
  height: 150px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #08131f;
}

.learning-dashboard,
.tool-grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 18px;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

.stat-tile {
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
}

.stat-tile span {
  display: block;
  color: var(--muted);
  font-size: 0.82rem;
}

.stat-tile strong {
  display: block;
  margin-top: 5px;
  color: var(--primary);
  font-size: 1.45rem;
}

.progress-track {
  height: 12px;
  overflow: hidden;
  border-radius: 999px;
  background: rgba(15, 118, 110, 0.12);
}

.progress-track span {
  display: block;
  width: 0;
  height: 100%;
  border-radius: inherit;
  background: linear-gradient(90deg, var(--primary), var(--accent));
  transition: width 0.5s ease;
}

.mode-switch,
.answer-line {
  display: flex;
  flex-wrap: wrap;
  gap: 12px;
  align-items: center;
}

.step-toggle {
  padding: 10px 14px;
}

.practice-shell {
  max-width: 850px;
  margin: 22px auto;
}

.practice-meta {
  display: flex;
  justify-content: space-between;
  gap: 18px;
}

.exam-meta {
  text-align: right;
}

.exam-meta span,
.exam-meta strong {
  display: block;
}

.exercise-question {
  min-height: 70px;
  font-size: 1.2rem;
  line-height: 1.7;
}

.answer-form input,
.tool-form input,
.tool-form select {
  min-height: 46px;
  padding: 10px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-soft);
  color: var(--ink);
  font: inherit;
}

.answer-line input {
  flex: 1;
  min-width: 180px;
}

.feedback {
  padding: 14px;
  border-radius: 12px;
}

.feedback.success {
  color: #126044;
  background: #dff7eb;
}

.feedback.error {
  color: #8b2e2e;
  background: #ffe6e3;
}

.solution-steps {
  display: grid;
  gap: 9px;
  padding: 16px 16px 16px 38px;
  border-left: 4px solid var(--primary);
  background: rgba(15, 118, 110, 0.07);
}

.exam-result {
  max-width: 620px;
  margin: 30px auto;
  text-align: center;
}

.exam-result > strong {
  display: block;
  color: var(--primary);
  font-size: 4rem;
}

.tool-form {
  display: grid;
  gap: 10px;
}

.tool-result {
  display: block;
  margin-top: 16px;
  padding: 18px;
  border-radius: 12px;
  background: rgba(15, 118, 110, 0.09);
  color: var(--primary);
  font-size: 1.35rem;
  font-weight: 700;
}

.triangle-simulator {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(260px, 0.8fr);
  gap: 20px;
}

.ratio-visual {
  display: grid;
  grid-template-columns: minmax(0, 1.2fr) minmax(220px, 0.8fr);
  gap: 18px;
  align-items: center;
  margin: 22px 0;
}

.ratio-summary {
  display: grid;
  gap: 12px;
}

.ratio-summary > div {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: rgba(15, 118, 110, 0.06);
}

.ratio-summary span {
  color: var(--muted);
}

.ratio-summary strong {
  color: var(--primary);
}

.slope-lab {
  display: grid;
  grid-template-columns: minmax(0, 1.25fr) minmax(260px, 0.75fr);
  gap: 20px;
  margin-top: 22px;
}

.slope-canvas {
  height: 360px;
}

.slope-values {
  grid-template-columns: repeat(2, 1fr);
}

.slope-exercises {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
  margin-top: 18px;
}

.mini-feedback {
  min-height: 24px;
  margin-bottom: 0;
  font-weight: 600;
}

.mini-feedback.success {
  color: #126044;
}

.mini-feedback.error {
  color: #8b2e2e;
}

.notable-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  margin: 20px 0;
}

.notable-button {
  min-width: 68px;
  padding: 10px 14px;
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--bg-soft);
  color: var(--ink);
  font: inherit;
  font-weight: 700;
  cursor: pointer;
  transition:
    transform 0.2s ease,
    background 0.2s ease,
    color 0.2s ease;
}

.notable-button:hover {
  transform: translateY(-2px);
}

.notable-button.active {
  border-color: var(--primary);
  background: var(--primary);
  color: white;
}

.notable-layout {
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(260px, 0.9fr);
  gap: 20px;
  align-items: center;
}

.notable-circle {
  display: block;
  width: 100%;
  height: 390px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: #08131f;
}

.notable-heading {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 14px;
  margin-bottom: 14px;
}

.notable-heading strong {
  color: var(--primary);
  font-size: 2.2rem;
}

.notable-heading span {
  color: var(--muted);
}

.notable-values {
  display: grid;
  gap: 10px;
}

.notable-values > div {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  padding: 14px;
  border: 1px solid var(--line);
  border-radius: 12px;
}

.notable-values span {
  color: var(--muted);
}

.notable-values strong {
  color: var(--primary);
  font-size: 1.15rem;
}

.notable-graphs {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 14px;
  margin-top: 18px;
}

.notable-graphs canvas {
  width: 100%;
  height: 170px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: #08131f;
}

.memory-strip {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 16px;
  margin-top: 16px;
  padding: 16px;
  border-radius: 14px;
  background: rgba(15, 118, 110, 0.07);
  line-height: 1.6;
}

.quotient-examples {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 14px;
}

.worked-quotient {
  padding: 16px 18px;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--card);
}

.worked-quotient summary {
  color: var(--primary);
  font-size: 1.05rem;
  font-weight: 700;
  cursor: pointer;
}

.worked-quotient p {
  overflow-x: auto;
}

.bank-toolbar {
  display: grid;
  grid-template-columns: minmax(180px, 0.7fr) minmax(180px, 0.7fr) 1fr;
  gap: 18px;
  align-items: end;
}

.bank-toolbar label {
  display: block;
  margin-bottom: 7px;
  font-weight: 700;
}

.bank-toolbar select {
  width: 100%;
  min-height: 46px;
  padding: 9px 12px;
  border: 1px solid var(--line);
  border-radius: 10px;
  background: var(--bg-soft);
  color: var(--ink);
  font: inherit;
}

.bank-progress {
  display: grid;
  gap: 7px;
}

.bank-progress span {
  color: var(--muted);
  font-size: 0.82rem;
}

.exercise-theme {
  padding-top: 24px;
}

.difficulty-group {
  margin: 24px 0;
}

.difficulty-group > h3 {
  display: flex;
  align-items: center;
  gap: 9px;
}

.difficulty-dot {
  width: 11px;
  height: 11px;
  border-radius: 50%;
}

.difficulty-dot.easy {
  background: #45a878;
}

.difficulty-dot.medium {
  background: #d5a229;
}

.difficulty-dot.semihard {
  background: #df7b36;
}

.difficulty-dot.hard {
  background: #c64e55;
}

.plain-exercise-list {
  display: grid;
  gap: 10px;
}

.plain-exercise {
  display: grid;
  grid-template-columns: auto 34px 1fr;
  gap: 12px;
  align-items: start;
  padding: 16px;
  border: 1px solid var(--line);
  border-radius: 14px;
  background: var(--card);
  line-height: 1.55;
  cursor: pointer;
  transition:
    opacity 0.2s ease,
    transform 0.2s ease;
}

.plain-exercise:hover {
  transform: translateX(3px);
}

.plain-exercise input {
  width: 18px;
  height: 18px;
  margin-top: 3px;
  accent-color: var(--primary);
}

.plain-number {
  color: var(--primary);
  font-weight: 700;
}

.plain-exercise.completed {
  opacity: 0.58;
}

.plain-exercise.completed > span:last-child {
  text-decoration: line-through;
}

.interpretation-note {
  border-left: 5px solid var(--primary);
}

.ratio-color-key {
  display: flex;
  flex-wrap: wrap;
  gap: 9px;
  margin-top: 16px;
}

.ratio-chip {
  padding: 8px 12px;
  border-radius: 999px;
  font-size: 0.83rem;
  font-weight: 700;
}

.ratio-chip.sen {
  background: #ffe0e9;
  color: #9d3152;
}

.ratio-chip.cos {
  background: #fff0bd;
  color: #765600;
}

.ratio-chip.tan {
  background: #dff8ed;
  color: #17694b;
}

.ratio-chip.reciprocal {
  background: #e9e1ff;
  color: #594293;
}

.resolved-list {
  display: grid;
  gap: 18px;
}

.resolved-card {
  display: grid;
  grid-template-columns: 56px minmax(0, 1fr);
  gap: 18px;
  padding: 24px;
  border: 1px solid var(--line);
  border-radius: 20px;
  background: var(--card);
  box-shadow: var(--shadow);
}

.resolved-card.identity-resolution {
  border-top: 5px solid #7d65ba;
}

.resolved-card.triangle-resolution {
  border-top: 5px solid var(--primary);
}

.resolved-number {
  display: grid;
  width: 50px;
  height: 50px;
  place-items: center;
  border-radius: 15px;
  background: rgba(15, 118, 110, 0.1);
  color: var(--primary);
  font-weight: 700;
}

.resolved-card h3 {
  margin: 4px 0 14px;
  overflow-x: auto;
}

.method-badge {
  display: inline-flex;
  margin: -4px 0 12px;
  padding: 7px 11px;
  border-radius: 999px;
  font-size: 0.78rem;
  font-weight: 700;
}

.method-badge.function-method {
  background: #dff8ed;
  color: #17694b;
}

.method-badge.algebra-method {
  background: #e9e1ff;
  color: #594293;
}

.math-steps {
  margin: 14px 0;
  padding: 14px 18px;
  overflow-x: auto;
  border-left: 4px solid var(--primary);
  border-radius: 8px;
  background: rgba(15, 118, 110, 0.06);
}

.step-caption {
  display: flex;
  gap: 11px;
  align-items: flex-start;
  margin: 16px 0 6px;
  color: var(--ink);
  font-weight: 700;
}

.step-caption:first-child {
  margin-top: 0;
}

.step-caption span {
  display: grid;
  flex: 0 0 30px;
  height: 30px;
  place-items: center;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  font-size: 0.82rem;
}

.domain-note,
.verification-note {
  padding: 12px 14px;
  border-radius: 11px;
  line-height: 1.55;
}

.domain-note {
  background: #fff1cf;
  color: #6c4d08;
}

.verification-note {
  background: #e4f6ec;
  color: #185f45;
}

.resolved-result {
  padding: 13px 16px;
  border-radius: 12px;
  border: 1px solid rgba(231, 111, 81, 0.24);
  background: rgba(231, 111, 81, 0.12);
  color: var(--ink);
  font-weight: 700;
}

.solved-exercises {
  display: grid;
  gap: 14px;
}

.solved-exercise {
  display: grid;
  grid-template-columns: 54px 1fr;
  gap: 16px;
  padding: 20px;
  border: 1px solid var(--line);
  border-radius: 18px;
  background: var(--card);
}

.exercise-number {
  display: grid;
  width: 46px;
  height: 46px;
  place-items: center;
  border-radius: 14px;
  background: rgba(15, 118, 110, 0.1);
  color: var(--primary);
  font-weight: 700;
}

.exercise-kind {
  color: var(--muted);
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
}

.exercise-kind.practical {
  color: var(--accent);
}

.solved-exercise h3 {
  margin: 5px 0 8px;
}

.solved-exercise details {
  margin-top: 12px;
  border-top: 1px solid var(--line);
}

.solved-exercise summary {
  padding: 13px 0 6px;
  color: var(--primary);
  font-weight: 700;
  cursor: pointer;
}

.solved-exercise li {
  margin: 7px 0;
  line-height: 1.55;
}

.reveal {
  animation: rise-in 0.5s ease both;
}

@keyframes rise-in {
  from {
    opacity: 0;
    transform: translateY(10px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 800px) {
  .concept-grid,
  .graph-grid,
  .identity-grid,
  .angle-grid,
  .identity-origin {
    grid-template-columns: 1fr;
  }

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

  .observer-box {
    grid-template-columns: 1fr;
  }

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

  .sync-graphs,
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .learning-dashboard,
  .tool-grid,
  .triangle-simulator,
  .ratio-visual,
  .slope-lab,
  .notable-layout {
    grid-template-columns: 1fr;
  }

  .slope-exercises,
  .quotient-examples {
    grid-template-columns: 1fr;
  }

  .notable-graphs {
    grid-template-columns: 1fr;
  }

  .bank-toolbar {
    grid-template-columns: 1fr;
  }

  .resolved-card {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 480px) {
  .comparison {
    grid-template-columns: 1fr;
  }

  .lab-canvas {
    height: 340px;
  }

  .live-values {
    grid-template-columns: 1fr;
  }

  .sync-graphs,
  .stats-grid {
    grid-template-columns: 1fr;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}