/* ==========================================================================
   STRAND HAIR STUDIO — Core Design System & Tokens
   Editorial · Fashion-Forward · Strong Contrast · Warm Amber Glow
   Conforms strictly to ops/design/design-standards-v1.md
   ========================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Playfair+Display:ital,wght@0,600;0,700;1,400;1,600&family=Plus+Jakarta+Sans:wght@400;500;600;700&display=swap');

:root {
  /* 1. Color Palette: 1 Primary + 1 Accent + 3 Neutrals */
  --color-primary: #0D0D11;         /* Deep Stark Obsidian Noir */
  --color-accent: #C88A58;          /* Warm Editorial Amber / Hair Copper */
  --color-accent-light: #E5B288;    /* Lighter Tint for Borders & Badges */
  --color-accent-glow: rgba(200, 138, 88, 0.22); /* Warm Ambient Glow */
  
  --neutral-bg-page: #FFFFFF;       /* Base Canvas White */
  --neutral-bg-section: #F9F9FB;    /* Subtle Warm Gray / Off-White */
  --neutral-bg-card: #FFFFFF;       /* Pure White Card Surface */
  --neutral-bg-dark: #0D0D11;       /* Dark Section Fill */
  --neutral-bg-dark-card: #15151C;  /* Dark Surface Card */
  
  --color-text-main: #111216;       /* Near Black for High-Contrast Reading */
  --color-text-muted: #5B5D68;      /* Mid Neutral for Secondary Information */
  --color-text-light: #8E909B;      /* Light Neutral for Metadata */
  --color-text-on-dark: #F5F5F7;    /* Crisp Off-White on Dark */
  --color-text-on-dark-muted: #9D9EA8; /* Muted Secondary on Dark */
  
  --border-light: rgba(13, 13, 17, 0.08); /* Crisp 1px Hairline on Light */
  --border-dark: rgba(255, 255, 255, 0.12); /* Subtle 1px Hairline on Dark */
  --border-accent: rgba(200, 138, 88, 0.4);

  /* 2. Typography: 2 Families, Strict 7 Type Sizes */
  --font-heading: 'Playfair Display', Georgia, serif;
  --font-body: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  
  --text-xs: 0.75rem;    /* 12px - Eyebrows & Tags */
  --text-sm: 0.875rem;   /* 14px - Meta & Captions */
  --text-base: 1rem;     /* 16px - Body Regular */
  --text-md: 1.25rem;    /* 20px - Subheadings & Lead */
  --text-lg: 1.5rem;     /* 24px - Section H3 */
  --text-xl: 2rem;       /* 32px - Section H2 */
  --text-xxl: 2.75rem;   /* 44px - Hero Main H1 */

  /* 3. Radius & Elevation */
  --radius-main: 6px;
  --shadow-warm-sm: 0 2px 8px rgba(13, 13, 17, 0.04);
  --shadow-warm-card: 0 4px 20px rgba(13, 13, 17, 0.06), 0 1px 3px rgba(13, 13, 17, 0.03);
  --shadow-warm-glow: 0 0 20px var(--color-accent-glow);
  --shadow-btn-glow: 0 4px 14px rgba(200, 138, 88, 0.32);

  /* Layout Constraints */
  --container-max: 1200px;
  --container-narrow: 920px;
  --header-height: 76px;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  background-color: var(--neutral-bg-page);
  color: var(--color-text-main);
}

body {
  font-family: var(--font-body);
  font-weight: 400;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  padding-bottom: 52px; /* Spacing for floating demo bar */
}

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

a {
  color: inherit;
  text-decoration: none;
  transition: color 0.2s ease;
}

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

/* Accessible focus outlines */
:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

/* Reduced Motion Override */
@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;
  }
}

/* ==========================================================================
   Typography Standards
   ========================================================================== */
h1, h2, h3, h4 {
  font-family: var(--font-heading);
  font-weight: 700;
  line-height: 1.2;
  color: var(--color-primary);
  letter-spacing: -0.01em;
}

h1 { font-size: var(--text-xxl); }
h2 { font-size: var(--text-xl); }
h3 { font-size: var(--text-lg); }
h4 { font-size: var(--text-md); }

p {
  color: var(--color-text-muted);
  font-size: var(--text-base);
}

.eyebrow {
  display: inline-block;
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--color-accent);
  margin-bottom: 12px;
}

/* ==========================================================================
   Layout Containers & Grid
   ========================================================================== */
.container {
  width: 100%;
  max-width: var(--container-max);
  margin-left: auto;
  margin-right: auto;
  padding-left: 24px;
  padding-right: 24px;
}

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

.section {
  padding: 80px 0;
  position: relative;
}

.section-dark {
  background-color: var(--neutral-bg-dark);
  color: var(--color-text-on-dark);
}
.section-dark h1,
.section-dark h2,
.section-dark h3,
.section-dark h4 {
  color: #FFFFFF;
}
.section-dark p {
  color: var(--color-text-on-dark-muted);
}
.section-dark .eyebrow {
  color: var(--color-accent-light);
}

/* Warm Editorial Glow for Dark Sections */
.glow-backdrop {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: radial-gradient(circle at 50% 15%, rgba(200, 138, 88, 0.16) 0%, rgba(13, 13, 17, 0) 65%);
  pointer-events: none;
}

.section-alt {
  background-color: var(--neutral-bg-section);
  border-top: 1px solid var(--border-light);
  border-bottom: 1px solid var(--border-light);
}

.section-header {
  text-align: center;
  max-width: 640px;
  margin: 0 auto 52px auto;
}

.section-header h2 {
  margin-bottom: 12px;
}

/* Responsive Grids */
.grid-2 {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 32px;
}

.grid-3 {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 32px;
}

.grid-4 {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 24px;
}

@media (max-width: 992px) {
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 680px) {
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .section { padding: 56px 0; }
  .container { padding-left: 16px; padding-right: 16px; }
  h1 { font-size: 2.1rem; }
  h2 { font-size: 1.65rem; }
}

/* ==========================================================================
   Header & Navigation
   ========================================================================== */
.site-header {
  position: sticky;
  top: 0;
  z-index: 1000;
  height: var(--header-height);
  background: rgba(255, 255, 255, 0.94);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border-light);
  transition: all 0.2s ease;
}

.site-header-dark {
  background: rgba(13, 13, 17, 0.94);
  border-bottom: 1px solid var(--border-dark);
}

.header-inner {
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-link {
  display: flex;
  align-items: center;
  gap: 10px;
  height: 44px;
}
.brand-link img, .brand-link svg {
  height: 38px;
  width: auto;
}

.main-nav {
  display: flex;
  align-items: center;
  gap: 28px;
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-main);
  letter-spacing: 0.02em;
  padding: 8px 0;
  position: relative;
}

.site-header-dark .nav-link {
  color: var(--color-text-on-dark);
}

.nav-link:hover {
  color: var(--color-accent);
}

.nav-link.active {
  color: var(--color-accent);
  font-weight: 600;
}
.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  right: 0;
  height: 2px;
  background-color: var(--color-accent);
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 16px;
}

/* Language Switcher */
.lang-switcher {
  display: flex;
  align-items: center;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-main);
  padding: 3px;
  background: #FFFFFF;
}
.site-header-dark .lang-switcher {
  background: #181822;
  border-color: var(--border-dark);
}

.lang-btn {
  background: transparent;
  border: none;
  font-size: var(--text-xs);
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 4px;
  cursor: pointer;
  color: var(--color-text-muted);
  transition: all 0.15s ease;
  min-height: 28px;
  display: inline-flex;
  align-items: center;
}
.site-header-dark .lang-btn {
  color: var(--color-text-on-dark-muted);
}
.lang-btn.active {
  background: var(--color-accent);
  color: #FFFFFF;
}

/* Hamburger toggle for mobile */
.menu-toggle {
  display: none;
  background: transparent;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-main);
  padding: 8px;
  width: 44px;
  height: 44px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
}
.site-header-dark .menu-toggle {
  border-color: var(--border-dark);
}
.menu-toggle span {
  display: block;
  width: 20px;
  height: 2px;
  background-color: var(--color-primary);
  margin: 4px 0;
  transition: all 0.2s ease;
}
.site-header-dark .menu-toggle span {
  background-color: #FFFFFF;
}

@media (max-width: 900px) {
  .main-nav { display: none; }
  .menu-toggle { display: flex; }
}

/* Mobile Drawer */
.mobile-drawer {
  position: fixed;
  top: var(--header-height);
  left: 0;
  right: 0;
  bottom: 0;
  background: #FFFFFF;
  z-index: 999;
  padding: 32px 24px;
  display: none;
  flex-direction: column;
  gap: 20px;
  overflow-y: auto;
}
.site-header-dark + .mobile-drawer {
  background: #0D0D11;
}
.mobile-drawer.open {
  display: flex;
}
.mobile-drawer .nav-link {
  font-size: var(--text-lg);
  padding: 12px 0;
  border-bottom: 1px solid var(--border-light);
}

/* ==========================================================================
   Buttons & Interactive Elements
   ========================================================================== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 24px;
  font-size: var(--text-sm);
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  border-radius: var(--radius-main);
  border: 2px solid transparent;
  cursor: pointer;
  text-align: center;
  transition: all 0.2s ease;
  min-height: 44px; /* Touch target standard */
  position: relative;
  white-space: normal;
  max-width: 100%;
}

.btn-primary {
  background-color: var(--color-primary);
  color: #FFFFFF;
  border-color: var(--color-primary);
}
.btn-primary:hover {
  background-color: #1F1F28;
  border-color: #1F1F28;
  transform: translateY(-2px);
  box-shadow: 0 4px 14px rgba(13, 13, 17, 0.2);
}

.btn-accent {
  background-color: var(--color-accent);
  color: #FFFFFF;
  border-color: var(--color-accent);
  box-shadow: var(--shadow-btn-glow);
}
.btn-accent:hover {
  background-color: #B57948;
  border-color: #B57948;
  transform: translateY(-2px);
  box-shadow: 0 6px 18px rgba(200, 138, 88, 0.45);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--border-light);
}
.btn-outline:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  transform: translateY(-2px);
}

.btn-outline-dark {
  background: transparent;
  color: #FFFFFF;
  border-color: var(--border-dark);
}
.btn-outline-dark:hover {
  border-color: var(--color-accent-light);
  color: var(--color-accent-light);
  transform: translateY(-2px);
}

.btn-sm {
  padding: 8px 16px;
  font-size: var(--text-xs);
  min-height: 36px;
}

/* ==========================================================================
   Cards, Tiles & Hover Standards
   ========================================================================== */
.card {
  background: var(--neutral-bg-card);
  border-radius: var(--radius-main);
  border: 2px solid transparent; /* Reserve border for zero layout shift */
  box-shadow: var(--shadow-warm-card);
  overflow: hidden;
  position: relative;
  transition: all 0.25s ease;
}

.card:hover {
  border-color: var(--color-accent);
  box-shadow: 0 8px 28px rgba(13, 13, 17, 0.08), var(--shadow-warm-glow);
  transform: translateY(-3px);
}

/* Dark Card */
.card-dark {
  background: var(--neutral-bg-dark-card);
  border: 2px solid transparent;
  color: var(--color-text-on-dark);
}
.card-dark:hover {
  border-color: var(--color-accent);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.4), var(--shadow-warm-glow);
  transform: translateY(-3px);
}

/* Selected state: border & glow, NO lift at rest */
.card.selected,
.card-dark.selected {
  border-color: var(--color-accent) !important;
  box-shadow: 0 0 16px var(--color-accent-glow) !important;
  transform: none !important;
}

.card-img {
  width: 100%;
  aspect-ratio: 4 / 3;
  object-fit: cover;
  background-color: #141419;
}

.card-body {
  padding: 24px;
}

/* Price Tag */
.price-tag {
  font-family: var(--font-heading);
  font-size: var(--text-lg);
  font-weight: 700;
  color: var(--color-primary);
}
.section-dark .price-tag {
  color: var(--color-accent-light);
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  font-size: var(--text-xs);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  padding: 4px 10px;
  border-radius: 4px;
  background: var(--neutral-bg-section);
  color: var(--color-text-muted);
  border: 1px solid var(--border-light);
}

.badge-accent {
  background: rgba(200, 138, 88, 0.12);
  color: var(--color-accent);
  border-color: rgba(200, 138, 88, 0.3);
}

/* ==========================================================================
   Before / After Interactive Component
   ========================================================================== */
.before-after-box {
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-main);
  aspect-ratio: 4 / 3;
  background: #141418;
  user-select: none;
}

.before-after-box img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

.ba-layer-after {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 1;
}

.ba-layer-before {
  position: absolute;
  top: 0;
  left: 0;
  width: 50%;
  height: 100%;
  overflow: hidden;
  z-index: 2;
  border-right: 2px solid #FFFFFF;
  box-shadow: 2px 0 10px rgba(0,0,0,0.5);
}

.ba-layer-before img {
  position: absolute;
  top: 0;
  left: 0;
  height: 100%;
  width: auto;
  max-width: none;
}

.ba-handle {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: #FFFFFF;
  color: var(--color-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  font-weight: bold;
  z-index: 3;
  box-shadow: 0 2px 10px rgba(0,0,0,0.3);
  pointer-events: none;
}

.ba-tag {
  position: absolute;
  bottom: 14px;
  padding: 4px 10px;
  font-size: var(--text-xs);
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  border-radius: 4px;
  z-index: 4;
}
.ba-tag-before {
  left: 14px;
  background: rgba(13, 13, 17, 0.75);
  color: #FFFFFF;
}
.ba-tag-after {
  right: 14px;
  background: var(--color-accent);
  color: #FFFFFF;
}

/* ==========================================================================
   Forms & Controls
   ========================================================================== */
.form-group {
  margin-bottom: 20px;
}

.form-label {
  display: block;
  font-size: var(--text-xs);
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--color-text-main);
  margin-bottom: 6px;
}
.section-dark .form-label {
  color: var(--color-text-on-dark);
}

.form-control {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid var(--border-light);
  border-radius: var(--radius-main);
  background-color: #FFFFFF;
  color: var(--color-text-main);
  font-size: var(--text-sm);
  transition: border-color 0.15s ease;
  min-height: 44px;
}
.section-dark .form-control {
  background-color: #171720;
  border-color: var(--border-dark);
  color: #FFFFFF;
}

.form-control:focus {
  border-color: var(--color-accent);
  outline: none;
  box-shadow: 0 0 0 3px var(--color-accent-glow);
}

/* ==========================================================================
   Admin Suite Styling (English Only)
   ========================================================================== */
.admin-shell {
  min-height: calc(100vh - 120px);
  background: #F4F4F7;
  padding: 24px 0 60px 0;
}

.admin-header-bar {
  background: #FFFFFF;
  border-bottom: 1px solid var(--border-light);
  padding: 16px 0;
  margin-bottom: 28px;
}

.admin-nav-tabs {
  display: flex;
  gap: 8px;
  border-bottom: 1px solid var(--border-light);
  margin-bottom: 24px;
  flex-wrap: wrap;
}

.admin-tab {
  padding: 10px 18px;
  font-size: var(--text-sm);
  font-weight: 600;
  color: var(--color-text-muted);
  border-bottom: 2px solid transparent;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 8px;
}
.admin-tab:hover {
  color: var(--color-primary);
}
.admin-tab.active {
  color: var(--color-accent);
  border-bottom-color: var(--color-accent);
}

.admin-table {
  width: 100%;
  border-collapse: collapse;
  background: #FFFFFF;
  border-radius: var(--radius-main);
  overflow: hidden;
  box-shadow: var(--shadow-warm-sm);
}
.admin-table th, .admin-table td {
  padding: 14px 18px;
  text-align: left;
  font-size: var(--text-sm);
  border-bottom: 1px solid var(--border-light);
}
.admin-table th {
  background: #FAFAFC;
  font-size: var(--text-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-light);
  font-weight: 600;
}
.admin-table tr:hover {
  background: #FDFCFA;
}

/* ==========================================================================
   Toast Notifications
   ========================================================================== */
.toast-container {
  position: fixed;
  bottom: 64px;
  right: 24px;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.toast {
  background: var(--color-primary);
  color: #FFFFFF;
  padding: 12px 20px;
  border-radius: var(--radius-main);
  box-shadow: 0 4px 16px rgba(0,0,0,0.25);
  border-left: 4px solid var(--color-accent);
  font-size: var(--text-sm);
  display: flex;
  align-items: center;
  gap: 10px;
  animation: toastIn 0.25s ease;
}

@keyframes toastIn {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ==========================================================================
   Global Concept Disclaimer & Footer
   ========================================================================== */
.demo-banner {
  background: #111116;
  color: #8E909B;
  font-size: var(--text-xs);
  padding: 8px 16px;
  text-align: center;
  border-bottom: 1px solid rgba(255,255,255,0.06);
}
.demo-banner strong {
  color: var(--color-accent-light);
}

.site-footer {
  background-color: var(--color-primary);
  color: #9D9EA8;
  padding: 64px 0 24px 0;
  border-top: 1px solid var(--border-dark);
}
.site-footer h4 {
  color: #FFFFFF;
  margin-bottom: 16px;
  font-size: var(--text-base);
}
.site-footer a:hover {
  color: var(--color-accent-light);
}

.footer-bottom {
  margin-top: 48px;
  padding-top: 24px;
  border-top: 1px solid rgba(255,255,255,0.08);
  font-size: var(--text-xs);
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 12px;
}

/* ==========================================================================
   Bottom Demo Floating Control Bar
   ========================================================================== */
.floating-demo-bar {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  height: 48px;
  background: rgba(13, 13, 17, 0.95);
  backdrop-filter: blur(10px);
  -webkit-backdrop-filter: blur(10px);
  border-top: 1px solid rgba(200, 138, 88, 0.35);
  z-index: 9998;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  font-size: var(--text-xs);
  color: #F5F5F7;
}

.demo-bar-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.demo-bar-tag {
  background: var(--color-accent);
  color: #FFFFFF;
  padding: 2px 7px;
  border-radius: 3px;
  font-weight: 700;
  font-size: 11px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
}

.demo-bar-links {
  display: flex;
  align-items: center;
  gap: 8px;
}

.demo-pill {
  padding: 4px 12px;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.1);
  color: #F5F5F7;
  font-weight: 600;
  font-size: 12px;
  transition: all 0.15s ease;
}
.demo-pill:hover {
  background: rgba(255, 255, 255, 0.2);
  color: #FFFFFF;
}
.demo-pill.active {
  background: #FFFFFF;
  color: var(--color-primary);
}

.demo-reset-btn {
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.2);
  color: #D1D2DA;
  padding: 4px 10px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 500;
  cursor: pointer;
}
.demo-reset-btn:hover {
  border-color: var(--color-accent);
  color: var(--color-accent-light);
}

@media (max-width: 600px) {
  .floating-demo-bar {
    padding: 0 12px;
    height: 44px;
  }
  .demo-bar-left span.demo-title {
    display: none;
  }
}

/* S3: readable Chinese controls and locally scrollable visit history. */
.card { min-width: 0; }
.lang-btn { white-space: nowrap; flex-shrink: 0; }
.client-history-table { min-width: 560px; }
@media (max-width: 600px) {
  .header-inner { gap: 8px; }
  .header-inner > .brand-link { flex: 0 0 88px; }
  .header-inner > .brand-link img { width: 88px; height: auto; }
  .header-actions { gap: 6px; }
  .header-actions .btn-sm { padding: 8px; font-size: 10px; white-space: nowrap; }
  .header-actions .menu-toggle { flex-shrink: 0; }
  .lang-btn { padding: 5px 7px; }
}