/* ===== base ===== */
body {
  background:lightblue;
  color: #fff;
  font-family: "Inter", "Helvetica Neue", Arial, sans-serif;
  letter-spacing: 0.03em;
}

/* ===== layout ===== */
.menu-wrapper {
  max-width: 960px;
  margin: 12vh auto 0;
  padding: 0 4%;
}

.menu-list {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 24px;
  justify-items: center;
}

/* ===== chapter card ===== */
.chapter {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  max-width: 200px;
  height: 120px;

  font-weight: 600;
  font-size: 1.1rem;
  color: #fff;
  text-decoration: none;

  border-radius: 18px;
  backdrop-filter: blur(6px);
  box-shadow:
    0 10px 25px rgba(0, 0, 0, 0.45),
    inset 0 0 0 1px rgba(255, 255, 255, 0.08);

  transition:
    transform 0.25s ease,
    box-shadow 0.25s ease,
    filter 0.25s ease;
}

.chapter:hover {
  transform: translateY(-6px);
  box-shadow:
    0 18px 40px rgba(0, 0, 0, 0.6),
    inset 0 0 0 1px rgba(255, 255, 255, 0.15);
  filter: brightness(1.05);
}

/* ===== color themes ===== */
.English {
  background: linear-gradient(135deg, #7f5af0, #6246ea);
}

.Politics {
  background: linear-gradient(135deg, #ff8f00, #ff6f00);
}

.JapaneseHistory {
  background: linear-gradient(135deg, #e63946, #c1121f);
}

.WorldHistory {
  background: linear-gradient(135deg, #43aa8b, #277da1);
}

/* ===== message ===== */
.message {
  margin-top: 6vh;
  text-align: center;
  font-size: 1.1rem;
  color: rgba(255, 255, 255, 0.75);
}

/* ===== footer ===== */
footer {
  margin-top: 12vh;
  text-align: center;
  font-size: 0.9rem;
  color: rgba(255, 255, 255, 0.4);
}

/* ===== responsive ===== */
@media screen and (min-width: 768px) {
  .chapter {
    height: 140px;
    font-size: 1.2rem;
  }

  .message {
    font-size: 1.2rem;
  }
}

@media screen and (min-width: 1024px) {
  .chapter {
    height: 160px;
    font-size: 1.3rem;
  }
}