/* =========================================================
   ひびきの音楽教室
   色や余白を変更したいときは、まずこの「基本設定」を調整してください。
   ========================================================= */

:root {
  --color-ink: #3d352f;
  --color-brown: #725946;
  --color-brown-dark: #48362a;
  --color-cream: #fffdf8;
  --color-sand: #f4eee4;
  --color-sage: #dfe9dc;
  --color-white: #ffffff;
  --color-line: #ddd2c3;
  --shadow: 0 14px 35px rgba(61, 53, 47, 0.1);
  --font-serif: "Hiragino Mincho ProN", "Yu Mincho", "Noto Serif JP", serif;
  --font-sans: "Hiragino Kaku Gothic ProN", "Yu Gothic", "Noto Sans JP", sans-serif;
  --content-width: 1120px;
}

* {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: 88px;
}

body {
  margin: 0;
  color: var(--color-ink);
  background: var(--color-cream);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.9;
}

img {
  display: block;
  width: 100%;
  height: auto;
}

a {
  color: inherit;
}

button,
a {
  -webkit-tap-highlight-color: transparent;
}

/* キーボード操作時に、現在選んでいる場所が見えるようにします。 */
:focus-visible {
  outline: 3px solid #b46a36;
  outline-offset: 4px;
}

.container {
  width: min(calc(100% - 40px), var(--content-width));
  margin-inline: auto;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.skip-link {
  position: fixed;
  top: 10px;
  left: 10px;
  z-index: 20;
  padding: 8px 14px;
  color: var(--color-white);
  background: var(--color-brown-dark);
  transform: translateY(-150%);
}

.skip-link:focus {
  transform: translateY(0);
}

/* 見出し共通 */
h1,
h2,
h3,
p {
  margin-top: 0;
}

h1,
h2,
h3 {
  font-family: var(--font-serif);
  font-weight: 600;
  line-height: 1.45;
}

h2 {
  margin-bottom: 28px;
  font-size: clamp(1.8rem, 3vw, 2.5rem);
}

h3 {
  font-size: 1.3rem;
}

.eyebrow {
  margin-bottom: 8px;
  color: var(--color-brown);
  font-family: var(--font-sans);
  font-size: 0.74rem;
  font-weight: 700;
  letter-spacing: 0.15em;
}

.section {
  padding: 112px 0;
}

.section--soft {
  background: var(--color-sand);
}

.section--accent {
  background: var(--color-sage);
}

.section-heading {
  margin-bottom: 48px;
  text-align: center;
}

.section-heading h2 {
  margin-bottom: 0;
}

/* 固有名詞や意味のまとまりの途中で改行されないようにします。 */
.no-break {
  white-space: nowrap;
}

/* ボタン共通 */
.button {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-height: 52px;
  padding: 12px 24px;
  border: 1px solid transparent;
  border-radius: 999px;
  text-decoration: none;
  font-weight: 700;
  line-height: 1.4;
  transition: transform 0.2s ease, background-color 0.2s ease;
}

.button:hover {
  transform: translateY(-2px);
}

.button--primary,
.button--small {
  color: var(--color-white);
  background: var(--color-brown-dark);
}

.button--small {
  min-height: 42px;
  padding: 9px 16px;
  font-size: 0.86rem;
}

.button--light {
  color: var(--color-brown-dark);
  background: var(--color-white);
}

/* ヘッダー */
.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: rgba(255, 253, 248, 0.94);
  border-bottom: 1px solid rgba(114, 89, 70, 0.15);
  backdrop-filter: blur(10px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  min-height: 76px;
  gap: 24px;
}

.site-logo {
  display: inline-flex;
  flex-direction: column;
  color: var(--color-brown-dark);
  font-family: var(--font-serif);
  font-size: 1.25rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  line-height: 1.35;
  text-decoration: none;
}

.site-logo__small {
  font-family: var(--font-sans);
  font-size: 0.58rem;
  letter-spacing: 0.13em;
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 24px;
  font-size: 0.9rem;
}

.site-nav > a:not(.button) {
  text-decoration: none;
}

.site-nav > a:not(.button):hover {
  color: var(--color-brown);
}

.menu-button {
  display: none;
}

/* ファーストビュー */
.hero {
  position: relative;
  min-height: min(650px, calc(100vh - 76px));
  overflow: hidden;
  color: var(--color-white);
  display: grid;
  align-items: center;
}

.hero__image {
  position: absolute;
  inset: 0;
  background:
    linear-gradient(90deg, rgba(41, 33, 25, 0.78) 0%, rgba(41, 33, 25, 0.58) 35%, rgba(41, 33, 25, 0.1) 72%),
    url("../images/hero-classroom.png") center / cover no-repeat;
}

.hero__content {
  position: relative;
  padding-top: 50px;
  padding-bottom: 50px;
}

.hero .eyebrow {
  color: #f6ddba;
}

.hero h1 {
  margin-bottom: 22px;
  font-size: clamp(2.3rem, 5vw, 4.3rem);
  letter-spacing: 0.04em;
}

.hero__lead {
  margin-bottom: 34px;
  font-size: clamp(1rem, 1.7vw, 1.2rem);
}

.hero .button--primary {
  color: var(--color-brown-dark);
  background: var(--color-white);
}

/* 教室について */
.split-layout,
.teacher {
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: clamp(40px, 7vw, 90px);
}

.split-layout__image img,
.teacher__image img {
  aspect-ratio: 4 / 3;
  object-fit: cover;
  border-radius: 4px;
  box-shadow: var(--shadow);
}

.split-layout__content p:not(.eyebrow),
.teacher__content p:not(.eyebrow) {
  margin-bottom: 20px;
}

/* 3つの特長 */
.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

.feature-card {
  min-height: 295px;
  padding: 34px 30px;
  background: var(--color-cream);
  border-top: 4px solid var(--color-brown);
}

.feature-card__number {
  display: block;
  margin-bottom: 26px;
  color: #a78e78;
  font-family: var(--font-serif);
  font-size: 1.2rem;
}

.feature-card h3 {
  margin-bottom: 18px;
}

.feature-card p {
  margin-bottom: 0;
  font-size: 0.94rem;
}

/* レッスン */
.lesson-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.lesson-card {
  overflow: hidden;
  background: var(--color-white);
  box-shadow: var(--shadow);
}

.lesson-card img {
  aspect-ratio: 3 / 2;
  object-fit: cover;
}

.lesson-card__body {
  padding: 28px 30px 32px;
}

.lesson-card__body h3 {
  margin-bottom: 12px;
}

.lesson-card__body p {
  margin-bottom: 0;
}

/* 「おすすめ」と「流れ」 */
.guide-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: clamp(48px, 10vw, 150px);
}

.guide-grid h2 {
  font-size: clamp(1.55rem, 2.5vw, 2rem);
}

.check-list,
.steps {
  padding: 0;
  margin: 0;
  list-style: none;
}

.check-list li {
  position: relative;
  padding: 11px 0 11px 32px;
  border-bottom: 1px solid rgba(61, 53, 47, 0.15);
}

.check-list li::before {
  position: absolute;
  top: 10px;
  left: 0;
  content: "✓";
  color: var(--color-brown);
  font-weight: 700;
}

.steps {
  counter-reset: step;
}

.steps li {
  display: flex;
  align-items: center;
  gap: 16px;
  padding: 10px 0;
}

.steps span {
  display: grid;
  width: 30px;
  height: 30px;
  flex: 0 0 30px;
  place-items: center;
  color: var(--color-white);
  background: var(--color-brown);
  border-radius: 50%;
  font-size: 0.78rem;
  font-weight: 700;
}

/* 講師より */
.teacher__image img {
  object-position: 80% center;
}

.note {
  padding: 13px 16px;
  background: var(--color-sand);
  color: #685d54;
  font-size: 0.88rem;
}

/* よくある質問 */
.faq-container {
  max-width: 800px;
}

.faq-list {
  border-top: 1px solid var(--color-line);
}

.faq-list details {
  border-bottom: 1px solid var(--color-line);
}

.faq-list summary {
  position: relative;
  padding: 20px 48px 20px 8px;
  cursor: pointer;
  font-weight: 700;
  list-style: none;
}

.faq-list summary::-webkit-details-marker {
  display: none;
}

.faq-list summary::after {
  position: absolute;
  top: 18px;
  right: 8px;
  content: "+";
  color: var(--color-brown);
  font-size: 1.6rem;
  font-weight: 400;
  line-height: 1;
}

.faq-list details[open] summary::after {
  content: "−";
}

.faq-list details p {
  padding: 0 8px 22px;
  margin-bottom: 0;
}

/* お問い合わせ */
.contact {
  padding: 96px 0;
  color: var(--color-white);
  background: var(--color-brown-dark);
  text-align: center;
}

.contact .eyebrow {
  color: #e7bd85;
}

.contact h2 {
  margin-bottom: 18px;
}

.contact__inner > p:not(.eyebrow):not(.contact__note) {
  max-width: 640px;
  margin: 0 auto 30px;
}

.contact__note {
  margin: 16px 0 0;
  color: #e6dace;
  font-size: 0.8rem;
}

/* フッター */
.site-footer {
  padding: 28px 0;
  background: #2f251f;
  color: #f5efe7;
}

.footer-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
}

.site-logo--footer {
  color: #f5efe7;
  font-size: 1rem;
}

.footer-inner p {
  margin: 0;
}

/* =========================================================
   スマホ表示（画面幅 760px 以下）
   ========================================================= */
@media (max-width: 760px) {
  html {
    scroll-padding-top: 70px;
  }

  .container {
    width: min(calc(100% - 32px), var(--content-width));
  }

  .section {
    padding: 76px 0;
  }

  .section-heading {
    margin-bottom: 34px;
  }

  .header-inner {
    min-height: 65px;
  }

  .site-logo {
    font-size: 1.05rem;
  }

  .menu-button {
    display: grid;
    width: 42px;
    height: 42px;
    padding: 10px;
    place-content: center;
    gap: 5px;
    background: transparent;
    border: 1px solid var(--color-line);
    border-radius: 2px;
    cursor: pointer;
  }

  .menu-button span[aria-hidden="true"] {
    display: block;
    width: 20px;
    height: 2px;
    background: var(--color-brown-dark);
    transition: transform 0.2s ease, opacity 0.2s ease;
  }

  /* 先頭のspanは読み上げ用テキストなので、2〜4番目が3本線です。 */
  .menu-button[aria-expanded="true"] span[aria-hidden="true"]:nth-of-type(2) {
    transform: translateY(7px) rotate(45deg);
  }

  .menu-button[aria-expanded="true"] span[aria-hidden="true"]:nth-of-type(3) {
    opacity: 0;
  }

  .menu-button[aria-expanded="true"] span[aria-hidden="true"]:nth-of-type(4) {
    transform: translateY(-7px) rotate(-45deg);
  }

  .site-nav {
    position: absolute;
    top: 65px;
    right: 0;
    left: 0;
    display: none;
    padding: 18px 16px 22px;
    background: var(--color-cream);
    border-bottom: 1px solid var(--color-line);
    box-shadow: 0 12px 18px rgba(61, 53, 47, 0.08);
  }

  .site-nav.is-open {
    display: grid;
    gap: 2px;
  }

  .site-nav > a:not(.button) {
    padding: 10px 6px;
  }

  .site-nav .button {
    margin-top: 8px;
  }

  .hero {
    min-height: 590px;
  }

  .hero__image {
    background:
      linear-gradient(90deg, rgba(41, 33, 25, 0.73) 0%, rgba(41, 33, 25, 0.38) 100%),
      url("../images/hero-classroom.png") 66% center / cover no-repeat;
  }

  .hero__content {
    padding-top: 68px;
  }

  .hero h1 {
    /* 1行目と2行目がそれぞれ収まるサイズにし、単語の途中で折り返さないようにします。 */
    font-size: clamp(1.4rem, 7vw, 2.25rem);
    letter-spacing: 0;
    line-height: 1.5;
  }

  /* 長い見出しも画面幅に合わせて、行の長さが偏らないようにします。 */
  h2 {
    font-size: clamp(1.55rem, 7vw, 2rem);
    letter-spacing: 0;
    text-wrap: balance;
  }

  /* カード見出しは、スマホでは十分な横幅があるため1行で読みやすく表示します。 */
  .feature-card h3 br {
    display: none;
  }

  .hero__lead br {
    display: none;
  }

  /* 教室についての見出しを、意図した位置で読みやすく改行します。 */
  .section--about h2 {
    font-size: clamp(1.4rem, 7vw, 2.1rem);
    letter-spacing: 0;
    line-height: 1.5;
  }

  .split-layout,
  .teacher,
  .guide-grid,
  .lesson-grid,
  .feature-grid {
    grid-template-columns: 1fr;
  }

  .split-layout,
  .teacher {
    gap: 34px;
  }

  .split-layout__image {
    order: 2;
  }

  .feature-grid {
    gap: 16px;
  }

  .feature-card {
    min-height: auto;
    padding: 27px 24px;
  }

  .feature-card__number {
    margin-bottom: 14px;
  }

  .lesson-grid {
    gap: 22px;
  }

  .lesson-card__body {
    padding: 22px;
  }

  .guide-grid {
    gap: 55px;
  }

  .teacher__image img {
    object-position: 70% center;
  }

  .contact {
    padding: 72px 0;
  }

  .contact .button {
    width: 100%;
  }

  .footer-inner {
    display: grid;
    justify-content: start;
  }
}

/* 端末幅では、意味のまとまりごとに見出しを必ず改行します。 */
@media (max-width: 900px) {
  .heading-mobile-line {
    display: block;
    white-space: nowrap;
  }
}

/* 動きが苦手な方の設定を尊重します。 */
@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  *,
  *::before,
  *::after {
    transition-duration: 0.01ms !important;
  }
}