:root {
  color-scheme: light;
  font-family: "Noto Sans JP", "Hiragino Kaku Gothic ProN", "Yu Gothic", sans-serif;
  color: #172b4d;
  background: #f4f8ff;
  font-synthesis: none;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  font-weight: 500;
}

* {
  box-sizing: border-box;
}

body {
  min-width: 320px;
  min-height: 100vh;
  margin: 0;
  background:
    radial-gradient(ellipse at 8% 8%, rgba(193, 225, 255, 0.5), transparent 34rem),
    #f4f8ff;
}

button,
input,
select {
  font: inherit;
}

.app {
  width: min(100% - 32px, 620px);
  margin: 0 auto;
  padding: 38px 0 24px;
}

.page-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 28px;
}

.brand-mark {
  display: grid;
  width: 52px;
  height: 52px;
  place-items: center;
  border-radius: 17px;
  background: #4b7bec;
  color: white;
  font-size: 2rem;
  font-weight: 800;
  box-shadow: 0 7px 16px rgba(75, 123, 236, 0.22);
}

.eyebrow {
  margin: 0 0 4px;
  color: #6680a3;
  font-size: 0.76rem;
  font-weight: 700;
  letter-spacing: 0.08em;
}

h1 {
  margin: 0;
  font-size: clamp(1.2rem, 4vw, 1.55rem);
  font-weight: 800;
  letter-spacing: 0.015em;
}

.practice-card {
  padding: clamp(22px, 6vw, 38px);
  border: 1px solid #e5ecf7;
  border-radius: 24px;
  background: #fff;
  box-shadow: 0 18px 50px rgba(51, 83, 129, 0.09);
}

.card-heading {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 28px;
}

h2 {
  margin: 0;
  font-size: 1.25rem;
  font-weight: 800;
}

.score {
  display: flex;
  align-items: center;
  gap: 7px;
  padding: 9px 13px;
  border-radius: 14px;
  background: #fff7da;
  color: #805e00;
  white-space: nowrap;
}

.score-icon {
  font-size: 1.25rem;
}

.score strong {
  font-size: 1.08rem;
}

.score-unit {
  padding-left: 3px;
  font-size: 0.75rem;
}

.grade-label,
.answer-label {
  display: block;
  margin-bottom: 8px;
  font-size: 0.9rem;
  font-weight: 750;
}

select,
input {
  width: 100%;
  min-height: 52px;
  border: 1.5px solid #d9e3f1;
  border-radius: 13px;
  background: #fff;
  color: #172b4d;
  outline: none;
}

select {
  padding: 0 15px;
  cursor: pointer;
}

select:focus,
input:focus {
  border-color: #4b7bec;
  box-shadow: 0 0 0 4px rgba(75, 123, 236, 0.13);
}

.question-panel {
  display: grid;
  min-height: 174px;
  align-content: center;
  justify-items: center;
  margin: 22px 0;
  padding: 20px;
  border-radius: 18px;
  background: #f2f7ff;
  text-align: center;
}

.question-label {
  margin: 0 0 12px;
  color: #6680a3;
  font-size: 0.85rem;
  font-weight: 700;
}

.question {
  margin: 0;
  color: #244a91;
  font-size: clamp(2rem, 9vw, 3.25rem);
  font-weight: 800;
  letter-spacing: 0.04em;
  overflow-wrap: anywhere;
}

.answer-row {
  display: flex;
  gap: 10px;
}

input {
  min-width: 0;
  padding: 0 14px;
  font-size: 1.05rem;
}

input::placeholder {
  color: #9aa9bd;
}

.button {
  display: inline-flex;
  min-height: 52px;
  align-items: center;
  justify-content: center;
  gap: 8px;
  border: 0;
  border-radius: 13px;
  cursor: pointer;
  font-weight: 750;
  transition: background-color 120ms ease, transform 120ms ease;
}

.button:not(:disabled):active {
  transform: translateY(1px);
}

.button:focus-visible {
  outline: 3px solid #172b4d;
  outline-offset: 3px;
}

.button-check {
  flex: 0 0 auto;
  padding: 0 17px;
  background: #4b7bec;
  color: #fff;
}

.button-check:hover {
  background: #3569dc;
}

.help-text {
  margin: 9px 0 0;
  color: #74869e;
  font-size: 0.8rem;
}

.feedback {
  min-height: 26px;
  margin: 14px 0 10px;
  font-weight: 750;
}

.feedback.correct {
  color: #17804a;
}

.feedback.incorrect,
.feedback.error {
  color: #bd3d48;
}

.button-next {
  width: 100%;
  background: #eaf0f8;
  color: #344b6b;
}

.button-next:not(:disabled) {
  background: #e3f5eb;
  color: #176b3f;
}

.button-next:not(:disabled):hover {
  background: #d1efdd;
}

.button:disabled {
  cursor: not-allowed;
  opacity: 0.65;
}

footer {
  padding: 22px 8px 0;
  color: #71839d;
  font-size: 0.86rem;
  text-align: center;
}

@media (max-width: 480px) {
  .app {
    width: min(100% - 24px, 620px);
    padding-top: 24px;
  }

  .page-header {
    margin-bottom: 20px;
  }

  .brand-mark {
    width: 46px;
    height: 46px;
    border-radius: 15px;
  }

  .card-heading {
    align-items: flex-start;
  }

  .score {
    padding: 7px 9px;
  }

  .answer-row {
    flex-direction: column;
  }

  .button-check {
    width: 100%;
  }
}

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