.problem {
  padding: var(--space-24) 0;
  background: var(--color-bg);
  border-top: 1px solid var(--color-border);
  border-bottom: 1px solid var(--color-border);
}

.problem__head {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: var(--space-16);
  align-items: center;
  margin-bottom: var(--space-16);
}

.problem__chart-wrap {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-5);
}

.problem__chart-title {
  font-size: var(--text-sm);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  text-align: center;
}

.chart-donut { width: 100%; max-width: 220px; }

.chart-donut__legend {
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  width: 100%;
  max-width: 240px;
}

.chart-donut__item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
}

.chart-donut__dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  flex-shrink: 0;
  margin-right: var(--space-2);
}

.chart-donut__label {
  display: flex;
  align-items: center;
  flex: 1;
}

.chart-donut__pct {
  font-weight: 700;
  color: var(--color-text-primary);
}

.problem__title {
  font-size: clamp(28px, 3.5vw, 42px);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.1;
  color: var(--color-text-primary);
  margin-bottom: var(--space-5);
}

.problem__sub {
  font-size: var(--text-lg);
  line-height: 1.7;
  color: var(--color-text-secondary);
}

.problem__grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--space-4);
}

.problem-card__stat {
  font-size: clamp(22px, 2vw, 28px);
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1;
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
}

.problem-card__title {
  font-size: var(--text-md);
  font-weight: 700;
  color: var(--color-text-primary);
  margin-bottom: var(--space-3);
}

.problem-card__desc {
  font-size: var(--text-base);
  line-height: 1.7;
  color: var(--color-text-secondary);
}

@media (max-width: 960px) {
  .problem__grid { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 760px) {
  .problem__head { grid-template-columns: 1fr; gap: var(--space-10); }
  .problem__chart-wrap { max-width: 280px; margin: 0 auto; }
}

@media (max-width: 480px) {
  .problem { padding: var(--space-16) 0; }
  .problem__grid { grid-template-columns: 1fr; }
  .problem__title { font-size: clamp(24px, 7vw, 32px); }
}