.mobile-bar {
  display: none;
}

@media (max-width: 900px) {
  html {
    scroll-padding-top: 118px;
  }

  body {
    overflow-x: hidden;
  }

  .mobile-bar {
    position: sticky;
    top: 0;
    z-index: 50;
    display: block;
    padding: 10px 14px 9px;
    background: rgba(7, 17, 27, .96);
    border-bottom: 1px solid #263c4e;
    backdrop-filter: blur(16px);
  }

  .mobile-brand {
    display: flex;
    align-items: center;
    gap: 9px;
    margin-bottom: 8px;
    font-size: 14px;
    font-weight: 800;
  }

  .mobile-brand b {
    display: grid;
    place-items: center;
    width: 28px;
    height: 28px;
    border-radius: 8px;
    background: #ff8426;
    color: #211004;
  }

  .mobile-bar nav {
    display: flex;
    gap: 7px;
    overflow-x: auto;
    padding-bottom: 2px;
    scrollbar-width: none;
  }

  .mobile-bar nav::-webkit-scrollbar {
    display: none;
  }

  .mobile-bar nav a {
    flex: 0 0 auto;
    padding: 7px 11px;
    border: 1px solid #2a4154;
    border-radius: 999px;
    background: #10202d;
    color: #c1ced8;
    font-size: 12px;
  }

  main {
    width: 100%;
    padding: 0 18px;
  }

  header {
    padding: 38px 0 30px;
  }

  header p {
    font-size: 16px;
  }

  .intro {
    padding: 22px 0;
  }

  .goal,
  .warning {
    padding: 18px;
  }

  .chapter-title {
    align-items: flex-start;
    margin-bottom: 14px;
  }

  .step {
    grid-template-columns: minmax(0, 1fr);
    gap: 20px;
    padding: 30px 0;
  }

  .copy {
    padding-left: 47px;
  }

  .copy p,
  .copy li {
    font-size: 16px;
    line-height: 1.65;
  }

  .shot,
  .stack {
    min-width: 0;
    max-width: 100%;
  }

  .shot img {
    max-width: 100%;
    height: auto;
  }

  .shot.natural {
    width: max-content;
    max-width: 100%;
    margin-inline: auto;
  }

  .target {
    width: 31px;
    height: 31px;
    border-width: 3px;
    font-size: 13px;
  }

  .arrow {
    width: 55px;
    height: 4px;
  }

  .arrow::after {
    top: -7px;
    border-left-width: 15px;
    border-top-width: 9px;
    border-bottom-width: 9px;
  }

  footer {
    margin-bottom: 35px;
  }
}

@media (max-width: 480px) {
  main {
    padding: 0 14px;
  }

  h1 {
    font-size: 36px;
  }

  .chapter {
    padding: 42px 0;
  }

  .chapter-title > span {
    width: 40px;
    height: 40px;
    flex: 0 0 40px;
  }

  .chapter-title h2 {
    font-size: 22px;
  }

  .copy h3 {
    font-size: 21px;
  }

  .number {
    width: 33px;
    height: 33px;
  }

  .result,
  .tip,
  .danger,
  .success {
    font-size: 14px;
  }

  footer {
    padding: 22px;
  }
}