/* ==========================================================================
   global.css — CSS Custom Properties, Reset, Base Typography
   合同会社 清援 (Seien Inc) Corporate Site
   ========================================================================== */

/* ---------- Google Fonts ---------- */
@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&family=Shippori+Mincho+B1:wght@500;600;700&family=Zen+Kaku+Gothic+New:wght@400;500;700&display=swap');

/* ---------- Custom Properties ---------- */
:root {
  /* Colors — Corporate */
  --corp-navy:        #1a2744;
  --corp-navy-light:  #2d3f5e;
  --corp-slate:       #475569;
  --corp-slate-light: #64748b;
  --corp-warm:        #b8860b;
  --corp-warm-light:  #d4a843;
  --corp-warm-dark:   #8b6914;
  --corp-warm-bg:     #faf7f2;
  --corp-white:       #ffffff;
  --corp-light-gray:  #f8fafc;
  --corp-border:      #e2e8f0;
  --corp-border-dark: #cbd5e1;
  --corp-success:     #059669;
  --corp-success-hover: #047857;
  --corp-line-green:  #06C755;
  --corp-line-hover:  #05b34c;
  --corp-error:       #dc2626;
  --corp-text-on-dark: #e2e8f0;
  --corp-text-muted:  #94a3b8;

  /* Typography */
  --font-heading: 'Shippori Mincho B1', 'Yu Mincho', serif;
  --font-body:    'Zen Kaku Gothic New', 'Hiragino Kaku Gothic ProN', 'Yu Gothic', sans-serif;
  --font-accent:  'Inter', sans-serif;

  /* Spacing scale (8px base) */
  --space-1:  0.25rem;  /* 4px */
  --space-2:  0.5rem;   /* 8px */
  --space-3:  0.75rem;  /* 12px */
  --space-4:  1rem;     /* 16px */
  --space-5:  1.25rem;  /* 20px */
  --space-6:  1.5rem;   /* 24px */
  --space-8:  2rem;     /* 32px */
  --space-10: 2.5rem;   /* 40px */
  --space-12: 3rem;     /* 48px */
  --space-16: 4rem;     /* 64px */
  --space-20: 5rem;     /* 80px */
  --space-24: 6rem;     /* 96px */

  /* Layout */
  --max-width:    1200px;
  --max-text:     800px;
  --header-height: 72px;
  --border-radius: 8px;
  --border-radius-lg: 16px;

  /* Shadows */
  --shadow-xs:  0 1px 2px rgba(0,0,0,0.04);
  --shadow-sm:  0 1px 3px rgba(0,0,0,0.06), 0 1px 2px rgba(0,0,0,0.04);
  --shadow-md:  0 4px 6px -1px rgba(0,0,0,0.07), 0 2px 4px -2px rgba(0,0,0,0.05);
  --shadow-lg:  0 10px 15px -3px rgba(0,0,0,0.08), 0 4px 6px -4px rgba(0,0,0,0.04);
  --shadow-xl:  0 20px 25px -5px rgba(0,0,0,0.08), 0 8px 10px -6px rgba(0,0,0,0.03);

  /* Transitions */
  --ease-out:   cubic-bezier(0.33, 1, 0.68, 1);
  --duration-fast: 150ms;
  --duration-base: 250ms;
  --duration-slow: 400ms;
}

/* ---------- Reset ---------- */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: var(--header-height);
}

body {
  font-family: var(--font-body);
  font-size: 1rem;
  line-height: 1.8;
  color: var(--corp-slate);
  background-color: var(--corp-white);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
}

img {
  height: auto;
}

input,
button,
textarea,
select {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
  border: none;
  background: none;
}

a {
  color: inherit;
  text-decoration: none;
}

ul,
ol {
  list-style: none;
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  color: var(--corp-navy);
  line-height: 1.4;
  letter-spacing: 0.02em;
}

/* ---------- Base Typography ---------- */
h1 {
  font-size: clamp(1.75rem, 4vw, 2.75rem);
  font-weight: 700;
}

h2 {
  font-size: clamp(1.5rem, 3.2vw, 2.25rem);
  font-weight: 700;
}

h3 {
  font-size: clamp(1.125rem, 2.4vw, 1.5rem);
  font-weight: 600;
}

h4 {
  font-size: clamp(1rem, 1.8vw, 1.25rem);
  font-weight: 600;
}

p {
  margin-bottom: var(--space-4);
}

p:last-child {
  margin-bottom: 0;
}

strong {
  font-weight: 700;
  color: var(--corp-navy);
}

small {
  font-size: 0.875rem;
}

/* Links in body text */
.content a {
  color: var(--corp-warm);
  text-decoration: underline;
  text-decoration-color: var(--corp-warm-light);
  text-underline-offset: 3px;
  transition: color var(--duration-fast) var(--ease-out);
}

.content a:hover {
  color: var(--corp-warm-dark);
}

/* Accent font for numbers/English */
.font-accent {
  font-family: var(--font-accent);
}

/* ---------- Container ---------- */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-6);
  padding-right: var(--space-6);
}

/* ---------- Section spacing ---------- */
.section {
  padding-top: var(--space-12);
  padding-bottom: var(--space-12);
}

.section--alt {
  background-color: var(--corp-warm-bg);
}

.section--light {
  background-color: var(--corp-light-gray);
}

.section--dark {
  background-color: var(--corp-navy);
  color: var(--corp-text-on-dark);
}

.section--dark h2,
.section--dark h3,
.section--dark h4 {
  color: var(--corp-white);
}

@media (min-width: 768px) {
  .section {
    padding-top: var(--space-20);
    padding-bottom: var(--space-20);
  }
}

/* ---------- Section headings ---------- */
.section-label {
  display: inline-block;
  font-family: var(--font-accent);
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--corp-warm);
  margin-bottom: var(--space-3);
}

.section-title {
  margin-bottom: var(--space-4);
  position: relative;
}

.section-title::after {
  content: '';
  display: block;
  width: 48px;
  height: 3px;
  background: var(--corp-warm);
  margin-top: var(--space-4);
  border-radius: 2px;
}

.section-title--center {
  text-align: center;
}

.section-title--center::after {
  margin-left: auto;
  margin-right: auto;
}

.section-subtitle {
  font-family: var(--font-body);
  font-size: 1.0625rem;
  color: var(--corp-slate-light);
  max-width: 640px;
  line-height: 1.8;
}

.section-subtitle--center {
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

/* ---------- Visually hidden (a11y) ---------- */
.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;
}

/* ---------- Selection ---------- */
::selection {
  background-color: var(--corp-warm);
  color: var(--corp-white);
}