/* 微差 (Bisa) — Landing Page Styles
 *
 * Design tokens: shared/design/tokens.json (Light/Dark を 1:1 マップ)
 * Font policy: Google Fonts は使わずシステム serif/sans に fallback
 * Build policy: ビルドツールチェインなし (vanilla CSS)
 */

:root {
  /* ── Colors (Light) ──────────────────────────────────────── */
  --color-bg: #F5F3EF;
  --color-surface: #FFFFFF;
  --color-accent: #6B8F71;
  --color-accent-dark: #4A6B50;
  --color-accent-light: #E8F0E9;
  --color-text-primary: #2C2C2C;
  --color-text-secondary: #6B6B6B;
  --color-text-tertiary: #8C8780;
  --color-divider: #E0DDD7;
  --color-corkboard: #E8DFD0;
  --color-on-accent: #FFFFFF;

  /* ── Spacing ─────────────────────────────────────────────── */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 12px;
  --space-lg: 16px;
  --space-xl: 24px;
  --space-2xl: 40px;
  --space-3xl: 64px;
  --space-section: 96px;

  /* ── Radius ──────────────────────────────────────────────── */
  --radius-md: 8px;
  --radius-lg: 12px;

  /* ── Typography ──────────────────────────────────────────── */
  --font-serif: "Hiragino Mincho ProN", "ヒラギノ明朝 ProN", "YuMincho", "游明朝", "Yu Mincho", "Noto Serif JP", "Noto Serif CJK JP", serif;
  --font-sans: -apple-system, BlinkMacSystemFont, "Hiragino Kaku Gothic ProN", "ヒラギノ角ゴ ProN W3", "Yu Gothic Medium", "游ゴシック Medium", "Noto Sans JP", "Helvetica Neue", Arial, sans-serif;

  /* ── Motion ──────────────────────────────────────────────── */
  --motion-duration: 350ms;
  --motion-ease: cubic-bezier(0.65, 0, 0.35, 1);

  /* ── Layout ──────────────────────────────────────────────── */
  --container-max: 1080px;
  --container-narrow: 720px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #1C1B19;
    --color-surface: #2A2825;
    --color-accent: #7DA882;
    --color-accent-dark: #5C7D62;
    --color-accent-light: #2E3A30;
    --color-text-primary: #E8E4DF;
    --color-text-secondary: #A09A92;
    --color-text-tertiary: #7A756D;
    --color-divider: #3D3A36;
    --color-corkboard: #35302A;
  }
}

/* ── Reset (minimal) ──────────────────────────────────────── */

*, *::before, *::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  background-color: var(--color-bg);
  color: var(--color-text-primary);
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img, picture, svg {
  max-width: 100%;
  height: auto;
  display: block;
}

a {
  color: var(--color-accent-dark);
  text-decoration: none;
  transition: color var(--motion-duration) var(--motion-ease);
}

a:hover {
  color: var(--color-accent);
}

@media (prefers-color-scheme: dark) {
  a {
    color: var(--color-accent);
  }
  a:hover {
    color: var(--color-accent-dark);
  }
}

:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
  border-radius: 2px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}

/* ── Layout ──────────────────────────────────────────────── */

.container {
  width: 100%;
  max-width: var(--container-max);
  margin-inline: auto;
  padding-inline: var(--space-xl);
}

.container--narrow {
  max-width: var(--container-narrow);
}

.section {
  padding-block: var(--space-section);
}

.section--tight {
  padding-block: var(--space-3xl);
}

/* ── Header ──────────────────────────────────────────────── */

.site-header {
  padding-block: var(--space-xl);
  border-bottom: 1px solid transparent;
}

.site-header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-lg);
}

.site-logo {
  font-family: var(--font-serif);
  font-size: 22px;
  font-weight: 500;
  letter-spacing: 0.08em;
  color: var(--color-text-primary);
}

.site-logo:hover {
  color: var(--color-text-primary);
}

.site-nav {
  display: flex;
  gap: var(--space-xl);
  font-size: 14px;
}

.site-nav a {
  color: var(--color-text-secondary);
}

.site-nav a:hover {
  color: var(--color-text-primary);
}

/* ── Hero ────────────────────────────────────────────────── */

.hero {
  padding-block: var(--space-3xl) var(--space-section);
}

.hero__inner {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3xl);
  align-items: center;
}

@media (min-width: 880px) {
  .hero__inner {
    grid-template-columns: 1.1fr 0.9fr;
    gap: var(--space-section);
  }
}

.hero__title {
  font-family: var(--font-serif);
  font-size: clamp(36px, 6vw, 56px);
  font-weight: 500;
  line-height: 1.4;
  letter-spacing: 0.04em;
  margin: 0 0 var(--space-xl);
  color: var(--color-text-primary);
}

.hero__lead {
  font-size: clamp(15px, 2vw, 17px);
  line-height: 1.9;
  color: var(--color-text-secondary);
  margin: 0 0 var(--space-2xl);
  max-width: 28em;
}

.hero__visual {
  display: flex;
  justify-content: center;
  align-items: center;
}

.hero__visual img {
  max-width: 320px;
  width: 100%;
  border-radius: var(--radius-lg);
  box-shadow: 0 20px 60px rgba(44, 44, 44, 0.08);
}

@media (prefers-color-scheme: dark) {
  .hero__visual img {
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
  }
}

/* ── CTA buttons ─────────────────────────────────────────── */

.cta-group {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-lg);
  align-items: center;
}

.cta {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  min-height: 52px;
  padding-inline: var(--space-xl);
  border-radius: var(--radius-lg);
  font-size: 15px;
  font-weight: 500;
  letter-spacing: 0.02em;
  text-decoration: none;
  transition: transform var(--motion-duration) var(--motion-ease),
              background-color var(--motion-duration) var(--motion-ease),
              border-color var(--motion-duration) var(--motion-ease),
              color var(--motion-duration) var(--motion-ease);
  white-space: nowrap;
}

.cta--primary {
  background-color: var(--color-text-primary);
  color: var(--color-bg);
  border: 1px solid var(--color-text-primary);
  padding-inline: var(--space-2xl);
}

.cta--primary:hover {
  color: var(--color-bg);
  background-color: var(--color-accent-dark);
  border-color: var(--color-accent-dark);
}

@media (prefers-color-scheme: dark) {
  .cta--primary:hover {
    background-color: var(--color-accent);
    border-color: var(--color-accent);
    color: var(--color-on-accent);
  }
}

.cta--primary .cta__badge {
  height: 22px;
  width: auto;
}

.cta--secondary {
  background-color: transparent;
  color: var(--color-text-primary);
  border: 1px solid var(--color-divider);
}

.cta--secondary:hover {
  color: var(--color-text-primary);
  border-color: var(--color-text-secondary);
}

.cta[aria-disabled="true"] {
  color: var(--color-text-tertiary);
  border-color: var(--color-divider);
  background-color: transparent;
  pointer-events: none;
  cursor: default;
}

.cta[aria-disabled="true"]:hover {
  color: var(--color-text-tertiary);
}

.cta__hint {
  font-size: 12px;
  letter-spacing: 0.05em;
  color: var(--color-text-tertiary);
  margin-left: var(--space-xs);
}

/* ── About (一文セクション) ───────────────────────────────── */

.about {
  background-color: var(--color-surface);
  border-block: 1px solid var(--color-divider);
}

.about__body {
  font-family: var(--font-serif);
  font-size: clamp(17px, 2.2vw, 20px);
  line-height: 2.2;
  letter-spacing: 0.04em;
  color: var(--color-text-primary);
  text-align: center;
  margin: 0;
}

.about__body p + p {
  margin-top: var(--space-lg);
}

/* ── Don't (やらないこと) ────────────────────────────────── */

.donts__title {
  font-family: var(--font-serif);
  font-size: clamp(22px, 3vw, 28px);
  font-weight: 500;
  letter-spacing: 0.06em;
  text-align: center;
  margin: 0 0 var(--space-2xl);
  color: var(--color-text-primary);
}

.donts__list {
  list-style: none;
  margin: 0 auto;
  padding: 0;
  max-width: 32em;
}

.donts__list li {
  padding: var(--space-md) 0;
  border-bottom: 1px solid var(--color-divider);
  font-size: 16px;
  color: var(--color-text-primary);
  line-height: 1.8;
  position: relative;
  padding-left: var(--space-xl);
}

.donts__list li::before {
  content: "—";
  position: absolute;
  left: 0;
  color: var(--color-text-tertiary);
}

.donts__caption {
  font-family: var(--font-serif);
  font-size: clamp(16px, 2vw, 19px);
  text-align: center;
  margin-top: var(--space-2xl);
  color: var(--color-accent-dark);
  letter-spacing: 0.05em;
}

@media (prefers-color-scheme: dark) {
  .donts__caption {
    color: var(--color-accent);
  }
}

/* ── Features ────────────────────────────────────────────── */

.features__title {
  font-family: var(--font-serif);
  font-size: clamp(22px, 3vw, 28px);
  font-weight: 500;
  letter-spacing: 0.06em;
  text-align: center;
  margin: 0 0 var(--space-3xl);
  color: var(--color-text-primary);
}

.features__grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-3xl);
}

@media (min-width: 720px) {
  .features__grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-section) var(--space-3xl);
  }
}

.feature {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: var(--space-xl);
}

.feature__visual {
  flex-shrink: 0;
}

.feature__visual img {
  max-width: 240px;
  width: 100%;
  border-radius: var(--radius-md);
  box-shadow: 0 12px 32px rgba(44, 44, 44, 0.06);
}

@media (prefers-color-scheme: dark) {
  .feature__visual img {
    box-shadow: 0 12px 32px rgba(0, 0, 0, 0.35);
  }
}

.feature__body {
  max-width: 22em;
}

.feature__title {
  font-family: var(--font-serif);
  font-size: 20px;
  font-weight: 500;
  letter-spacing: 0.06em;
  margin: 0 0 var(--space-md);
  color: var(--color-text-primary);
}

.feature__description {
  font-size: 15px;
  line-height: 1.85;
  color: var(--color-text-secondary);
  margin: 0;
}

/* ── AI Stance ───────────────────────────────────────────── */

.stance {
  background-color: var(--color-surface);
  border-block: 1px solid var(--color-divider);
}

.stance__body {
  font-family: var(--font-serif);
  font-size: clamp(17px, 2.2vw, 21px);
  line-height: 2.2;
  letter-spacing: 0.05em;
  color: var(--color-text-primary);
  text-align: center;
  margin: 0;
}

.stance__body p + p {
  margin-top: var(--space-lg);
}

.stance__quiet {
  display: block;
  font-size: 0.9em;
  color: var(--color-text-secondary);
  margin-top: var(--space-xl);
}

/* ── Footer ──────────────────────────────────────────────── */

.site-footer {
  border-top: 1px solid var(--color-divider);
  padding-block: var(--space-3xl);
}

.site-footer__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xl);
  text-align: center;
}

.site-footer__icon {
  width: 48px;
  height: 48px;
  border-radius: var(--radius-md);
}

.site-footer__nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: var(--space-lg) var(--space-xl);
  font-size: 14px;
}

.site-footer__nav a {
  color: var(--color-text-secondary);
}

.site-footer__nav a:hover {
  color: var(--color-text-primary);
}

.site-footer__copyright {
  font-size: 12px;
  color: var(--color-text-tertiary);
  letter-spacing: 0.08em;
}

/* ── Support page ────────────────────────────────────────── */

.support-hero {
  padding-block: var(--space-section) var(--space-3xl);
  text-align: center;
}

.support-hero__title {
  font-family: var(--font-serif);
  font-size: clamp(28px, 5vw, 40px);
  font-weight: 500;
  letter-spacing: 0.05em;
  margin: 0;
  color: var(--color-text-primary);
}

.support-hero__lead {
  margin: var(--space-xl) auto 0;
  max-width: 30em;
  color: var(--color-text-secondary);
  font-size: 15px;
  line-height: 1.9;
}

.faq {
  padding-block: var(--space-2xl) var(--space-section);
}

.faq__list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.faq__item {
  border-bottom: 1px solid var(--color-divider);
  padding-block: var(--space-lg);
}

.faq__item summary {
  cursor: pointer;
  font-family: var(--font-serif);
  font-size: 17px;
  font-weight: 500;
  letter-spacing: 0.04em;
  color: var(--color-text-primary);
  padding-right: var(--space-xl);
  position: relative;
  list-style: none;
}

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

.faq__item summary::after {
  content: "+";
  position: absolute;
  right: 0;
  top: 50%;
  transform: translateY(-50%);
  font-size: 22px;
  font-weight: 300;
  color: var(--color-text-tertiary);
  transition: transform var(--motion-duration) var(--motion-ease);
}

.faq__item[open] summary::after {
  content: "−";
}

.faq__item summary:hover {
  color: var(--color-accent-dark);
}

@media (prefers-color-scheme: dark) {
  .faq__item summary:hover {
    color: var(--color-accent);
  }
}

.faq__body {
  margin: var(--space-lg) 0 var(--space-sm);
  font-size: 15px;
  line-height: 1.95;
  color: var(--color-text-secondary);
  max-width: 36em;
}

.faq__body a {
  font-family: var(--font-sans);
}

/* ── 404 page ────────────────────────────────────────────── */

.notfound {
  min-height: 70vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--space-3xl) var(--space-xl);
}

.notfound__title {
  font-family: var(--font-serif);
  font-size: clamp(28px, 5vw, 40px);
  font-weight: 500;
  letter-spacing: 0.06em;
  margin: 0 0 var(--space-xl);
  color: var(--color-text-primary);
}

.notfound__lead {
  color: var(--color-text-secondary);
  font-size: 15px;
  margin: 0 0 var(--space-2xl);
}