:root {
  --color-bg: #fbfbfc;
  --color-bg-block: #fff;
  --color-text: #555;
  --color-sub-text: #888;
  --color-accent: #89c1ee;
  --color-border: #d9d9d9;
  --color-bg-copyright: #444;
  /* 差分ハイライト用 */
  --color-diff-ins-bg: #dcfce7;
  --color-diff-ins-text: #166534;
  --color-diff-del-bg: #fee2e2;
  --color-diff-del-text: #991b1b;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #101a24;
    --color-bg-block: #162030;
    --color-text: #e0e8f0;
    --color-sub-text: #888;
    --color-accent: #1e8fcf;
    --color-border: #283848;
    --color-bg-copyright: #444;
    --color-diff-ins-bg: #162e1e;
    --color-diff-ins-text: #7ed99a;
    --color-diff-del-bg: #3c1a1a;
    --color-diff-del-text: #f87171;
  }
}

* {
  box-sizing: border-box;
}

body {
  background: var(--color-bg);
  font-family: "Helvetica Neue", Arial, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
  line-height: 1.6;
  color: var(--color-text);
  margin: 0;
}

a {
  color: var(--color-accent);
  text-decoration: none;
}

a:hover {
  opacity: .7;
}

.br-sp {
  display: none;
}

@media (max-width: 767px) {
  .br-sp {
    display: block;
  }
}

.container {
  width: 100%;
  padding-left: 20px;
  padding-right: 20px;
  padding-top: 40px;
  padding-bottom: 40px;
  margin-left: auto;
  margin-right: auto;
}

@media (min-width: 768px) {
  .container {
    width: 1200px;
  }
}

.header-title {
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 22px;
  line-height: 1.5;
  letter-spacing: 0.12em;
  color: var(--color-text);
  font-weight: 700;
}

@media (max-width: 767px) {
  .header-title {
    font-size: 18px;
  }
}

.header-description {
  font-size: 13px;
  line-height: 2;
  text-align: center;
  letter-spacing: 0.04em;
  color: var(--color-sub-text);
  margin-bottom: 1.2rem;
}

@media (max-width: 767px) {
  .header-description {
    font-size: 11px;
  }
}

.diff-input-group {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
}

@media (min-width: 768px) {
  .diff-input-group {
    grid-template-columns: 1fr 1fr;
  }
}

.input-block {
  display: flex;
  flex-direction: column;
}

.label {
  font-size: 14px;
  margin-bottom: 8px;
}

.editable {
  width: 100%;
  min-height: 300px;
  font-size: 14px;
  line-height: 1.6;
  color: var(--color-text);
  white-space: pre-wrap;
  word-break: break-all;
  overflow-y: auto;
  background: var(--color-bg-block);
  border: 1px solid var(--color-border);
  border-radius: 4px;
  padding: 12px;
}

@media (min-width: 768px) {
  .editable {
    min-height: 700px;
  }
}

.editable:focus {
  border-color: var(--color-accent);
  outline: none;
}

.editable:empty::before {
  content: attr(data-placeholder);
  color: var(--color-border);
}

.button-container {
  text-align: center;
  margin-top: 30px;
  margin-bottom: 30px;
}

.btn-compare {
  display: inline-block;
  width: 200px;
  background: var(--color-accent);
  border: none;
  border-radius: 4px;
  color: #fff;
  font-size: 16px;
  font-weight: bold;
  letter-spacing: .1em;
  cursor: pointer;
  padding-top: 12px;
  padding-bottom: 12px;
}

@media (min-width: 768px) {
  .btn-compare {
    transition: opacity 0.2s;
  }
}

@media (min-width: 768px) {
  .btn-compare:hover {
    opacity: 0.8;
  }
}

.diff-ins {
  background: var(--color-diff-ins-bg);
  color: var(--color-diff-ins-text);
}

.diff-del {
  background: var(--color-diff-del-bg);
  color: var(--color-diff-del-text);
  text-decoration: line-through;
}

.sample-container {
  text-align: center;
  margin-bottom: 2rem;
}

.btn-sample {
  display: inline-block;
  background: none;
  border: 1px solid var(--color-border);
  border-radius: 4px;
  color: var(--color-text);
  font-size: 13px;
  cursor: pointer;
  padding-top: 8px;
  padding-bottom: 8px;
  padding-left: 16px;
  padding-right: 16px;
}

@media (min-width: 768px) {
  .btn-sample {
    transition: background 0.2s;
  }
}

@media (min-width: 768px) {
  .btn-sample:hover {
    background: var(--color-border);
  }
}

.editable .diff-row {
  border-radius: 2px;
}

@media (min-width: 768px) {
  .editable .diff-row {
    transition: background 0.1s;
  }
}

@media (min-width: 768px) {
  .editable .diff-row.is-hovered {
    background: rgba(128, 128, 128, 0.08);
  }
}

/* ===== フッター ===== */
.attention {
  text-align: center;
  padding-left: 20px;
  padding-right: 20px;
  padding-top: 56px;
  padding-bottom: 56px;
}

@media (max-width: 767px) {
  .attention {
    padding-top: 40px;
    padding-bottom: 40px;
  }
}

.attention-text {
  font-size: 12px;
  line-height: 2;
  letter-spacing: 0.04em;
  color: var(--color-sub-text);
}

@media (max-width: 767px) {
  .attention-text {
    font-size: 10px;
  }
}

.attention-text--brand {
  margin-top: 20px;
  letter-spacing: 0.1em;
}

.attention-text--brand::before {
  content: '';
  display: block;
  width: 20px;
  height: 1px;
  background: var(--color-text);
  margin: 2rem auto 1rem;
}

.service-link-text {
  font-size: 13px;
  line-height: 2;
  text-align: center;
  letter-spacing: 0.04em;
  color: var(--color-sub-text);
  margin-bottom: 1.2rem;
}

@media (max-width: 767px) {
  .service-link-text {
    font-size: 11px;
  }
}

.footer {
  text-align: center;
  background: var(--color-bg-copyright);
  padding-top: 20px;
  padding-bottom: 20px;
}

.footer-copyright {
  display: block;
  font-size: 11px;
  letter-spacing: 0.08em;
  color: #fff;
}

@media (max-width: 767px) {
  .footer-copyright {
    font-size: 10px;
  }
}