/* =========================================================
   Mandarin Mastery — V1 "Bold & Dark"
   HappyRobot-inspired: dark, confident, structured, abstract
   ========================================================= */

@import url('https://fonts.googleapis.com/css2?family=Instrument+Serif:ital@0;1&family=Geist:wght@300;400;500;600;700&family=Noto+Serif+SC:wght@400;600;700&display=swap');

:root {
  --bg: #0A0A0B;
  --bg-elev: #131316;
  --bg-elev-2: #1B1B20;
  --border: #26262C;
  --border-strong: #3A3A42;
  --text: #F5F5F2;
  --text-dim: #A3A3A8;
  --text-muted: #6B6B72;
  --accent: #E8472C;        /* imperial red */
  --accent-soft: #2A1410;
  --accent-glow: rgba(232, 71, 44, 0.35);
  --gold: #C9A356;

  --font-display: 'Instrument Serif', 'Times New Roman', serif;
  --font-body: 'Geist', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-zh: 'Noto Serif SC', serif;

  --maxw: 1240px;
  --pad-x: clamp(20px, 5vw, 48px);
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }

body {
  background: var(--bg);
  color: var(--text);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }

/* ---------- Layout ---------- */
.container {
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--pad-x);
}

.section {
  padding: clamp(80px, 12vw, 160px) 0;
  position: relative;
}

.section--tight { padding: clamp(60px, 8vw, 100px) 0; }

.section--light {
  background: #F5F5F2;
  --bg: #F5F5F2;
  --bg-elev: #FFFFFF;
  --bg-elev-2: #ECECE6;
  --text: #0A0A0B;
  --text-dim: #4A4A4F;
  --text-muted: #7A7A7F;
  --border: #D8D8D2;
  --border-strong: #B8B8B2;
  color: var(--text);
}

/* ---------- Header ---------- */
.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  background: rgba(10, 10, 11, 0.7);
  border-bottom: 1px solid var(--border);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 72px;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 var(--pad-x);
}

.logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-size: 22px;
  letter-spacing: -0.01em;
}

.logo-mark {
  width: 32px;
  height: 32px;
  display: grid;
  place-items: center;
  background: var(--accent);
  color: var(--text);
  font-family: var(--font-zh);
  font-weight: 700;
  font-size: 18px;
  border-radius: 6px;
  box-shadow: 0 0 24px var(--accent-glow);
}

.logo-mark span { transform: translateY(-1px); }

.nav {
  display: flex;
  gap: 36px;
  font-size: 14px;
  color: var(--text-dim);
  font-weight: 400;
}

.nav a {
  transition: color 0.2s ease;
  position: relative;
}

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

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

.nav a.active::after {
  content: '';
  position: absolute;
  bottom: -22px;
  left: 0;
  right: 0;
  height: 1px;
  background: var(--accent);
}

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 18px;
  font-size: 14px;
  font-weight: 500;
  border-radius: 8px;
  border: 1px solid var(--border-strong);
  background: var(--bg-elev);
  color: var(--text);
  cursor: pointer;
  transition: all 0.2s ease;
  font-family: inherit;
}

.btn:hover {
  border-color: var(--text-muted);
  background: var(--bg-elev-2);
  transform: translateY(-1px);
}

.btn-primary {
  background: var(--accent);
  border-color: var(--accent);
  color: white;
}

.btn-primary:hover {
  background: #F25538;
  border-color: #F25538;
  box-shadow: 0 8px 32px var(--accent-glow);
}

.btn-large { padding: 14px 28px; font-size: 15px; }

.btn-arrow::after {
  content: '→';
  transition: transform 0.2s ease;
}

.btn:hover .btn-arrow::after,
.btn-arrow:hover::after { transform: translateX(3px); }

/* ---------- Hero ---------- */
.hero {
  position: relative;
  padding: clamp(80px, 14vw, 180px) 0 clamp(60px, 10vw, 120px);
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: 0;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  height: 100%;
  background: radial-gradient(ellipse 800px 400px at 50% 0%, rgba(232, 71, 44, 0.12), transparent 60%);
  pointer-events: none;
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 6px 14px;
  border: 1px solid var(--border);
  border-radius: 100px;
  font-size: 12px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-dim);
  background: var(--bg-elev);
  margin-bottom: 32px;
}

.hero-eyebrow .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--accent);
  box-shadow: 0 0 12px var(--accent);
}

.hero-title {
  font-family: var(--font-display);
  font-size: clamp(48px, 8vw, 104px);
  line-height: 0.98;
  letter-spacing: -0.025em;
  font-weight: 400;
  max-width: 12ch;
  margin-bottom: 32px;
}

.hero-title em {
  font-style: italic;
  color: var(--accent);
  position: relative;
}

.hero-title .zh-accent {
  font-family: var(--font-zh);
  font-style: normal;
  color: var(--accent);
  font-size: 0.85em;
  font-weight: 600;
  margin: 0 0.1em;
}

.hero-sub {
  font-size: clamp(17px, 1.6vw, 20px);
  color: var(--text-dim);
  max-width: 56ch;
  margin-bottom: 40px;
  line-height: 1.5;
}

.hero-cta-row {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 80px;
}

.hero-visual {
  position: relative;
  border: 1px solid var(--border);
  border-radius: 20px;
  background: var(--bg-elev);
  overflow: hidden;
  aspect-ratio: 16 / 9;
  margin-top: 40px;
}

.hero-visual-inner {
  position: absolute;
  inset: 0;
  background:
    radial-gradient(circle at 30% 50%, rgba(232, 71, 44, 0.15), transparent 50%),
    radial-gradient(circle at 70% 30%, rgba(201, 163, 86, 0.08), transparent 50%),
    linear-gradient(135deg, #16161A 0%, #0E0E11 100%);
  display: grid;
  place-items: center;
}

.hero-character {
  font-family: var(--font-zh);
  font-size: clamp(180px, 28vw, 360px);
  font-weight: 700;
  color: transparent;
  -webkit-text-stroke: 1px rgba(245, 245, 242, 0.15);
  position: relative;
  animation: charFloat 8s ease-in-out infinite;
  user-select: none;
}

.hero-character.solid {
  position: absolute;
  -webkit-text-stroke: 0;
  background: linear-gradient(135deg, var(--accent) 0%, #C9A356 100%);
  -webkit-background-clip: text;
  background-clip: text;
  opacity: 0.85;
  font-size: clamp(80px, 12vw, 160px);
  top: 20%;
  right: 15%;
  animation: charFloat 6s ease-in-out infinite reverse;
}

.hero-character.small {
  position: absolute;
  -webkit-text-stroke: 0;
  color: var(--text-dim);
  opacity: 0.4;
  font-size: clamp(40px, 5vw, 70px);
  bottom: 18%;
  left: 12%;
  animation: charFloat 7s ease-in-out infinite 1s;
}

@keyframes charFloat {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-12px) rotate(-1deg); }
}

.hero-meta {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 24px;
  padding-top: 48px;
  border-top: 1px solid var(--border);
  margin-top: 40px;
}

.hero-meta-item .label {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.hero-meta-item .value {
  font-family: var(--font-display);
  font-size: 28px;
  letter-spacing: -0.01em;
}

.hero-meta-item .value .zh {
  font-family: var(--font-zh);
  color: var(--accent);
  margin-right: 8px;
  font-size: 0.9em;
}

/* ---------- Section heading ---------- */
.section-eyebrow {
  font-size: 12px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 20px;
  display: flex;
  align-items: center;
  gap: 12px;
}

.section-eyebrow::before {
  content: '';
  width: 24px;
  height: 1px;
  background: var(--accent);
}

.section-title {
  font-family: var(--font-display);
  font-size: clamp(36px, 5.5vw, 64px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  font-weight: 400;
  max-width: 18ch;
  margin-bottom: 24px;
}

.section-title em {
  font-style: italic;
  color: var(--accent);
}

.section-lead {
  font-size: 18px;
  color: var(--text-dim);
  max-width: 60ch;
  line-height: 1.55;
}

/* ---------- Numbered cards (HappyRobot style) ---------- */
.numbered-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  margin-top: 64px;
}

.numbered-card {
  background: var(--bg);
  padding: 36px 32px;
  position: relative;
  transition: background 0.3s ease;
}

.numbered-card:hover { background: var(--bg-elev); }

.numbered-card .num {
  font-family: var(--font-body);
  font-size: 12px;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  margin-bottom: 24px;
  display: block;
}

.numbered-card h3 {
  font-family: var(--font-display);
  font-size: 26px;
  font-weight: 400;
  letter-spacing: -0.01em;
  margin-bottom: 12px;
  line-height: 1.15;
}

.numbered-card h3 .zh {
  font-family: var(--font-zh);
  color: var(--accent);
  font-size: 0.9em;
  margin-right: 8px;
  font-weight: 600;
}

.numbered-card p {
  font-size: 15px;
  color: var(--text-dim);
  line-height: 1.55;
}

.numbered-card .meta {
  margin-top: 20px;
  padding-top: 20px;
  border-top: 1px solid var(--border);
  display: flex;
  gap: 16px;
  font-size: 13px;
  color: var(--text-muted);
}

/* ---------- Lessons (cards with image area) ---------- */
.lessons-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 24px;
  margin-top: 64px;
}

.lesson-card {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  transition: all 0.3s ease;
  display: flex;
  flex-direction: column;
}

.lesson-card:hover {
  border-color: var(--border-strong);
  transform: translateY(-4px);
}

.lesson-card-img {
  aspect-ratio: 4 / 3;
  background:
    linear-gradient(135deg, rgba(232, 71, 44, 0.08), rgba(201, 163, 86, 0.04)),
    var(--bg-elev-2);
  display: grid;
  place-items: center;
  position: relative;
  overflow: hidden;
}

.lesson-card-img::before {
  content: attr(data-zh);
  font-family: var(--font-zh);
  font-size: 120px;
  font-weight: 700;
  color: rgba(245, 245, 242, 0.06);
  position: absolute;
  inset: 0;
  display: grid;
  place-items: center;
  user-select: none;
}

.lesson-card-img img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  position: relative;
  z-index: 1;
  filter: grayscale(20%) brightness(0.85);
}

.lesson-card-body {
  padding: 28px 28px 32px;
  flex: 1;
  display: flex;
  flex-direction: column;
}

.lesson-card .tag {
  display: inline-block;
  padding: 4px 10px;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 11px;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  border-radius: 4px;
  margin-bottom: 16px;
  align-self: flex-start;
}

.lesson-card h3 {
  font-family: var(--font-display);
  font-size: 28px;
  font-weight: 400;
  margin-bottom: 12px;
  letter-spacing: -0.01em;
}

.lesson-card p {
  font-size: 15px;
  color: var(--text-dim);
  margin-bottom: 20px;
  flex: 1;
}

.lesson-card ul {
  list-style: none;
  padding: 0;
  margin: 0 0 24px 0;
}

.lesson-card ul li {
  padding: 8px 0;
  font-size: 14px;
  color: var(--text-dim);
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
}

.lesson-card ul li:last-child { border-bottom: 1px solid var(--border); }

.lesson-card ul li .zh {
  font-family: var(--font-zh);
  color: var(--text-muted);
  font-size: 12px;
}

/* ---------- About / Bio Section ---------- */
.about-grid {
  display: grid;
  grid-template-columns: 1fr 1.3fr;
  gap: 80px;
  align-items: start;
}

@media (max-width: 800px) {
  .about-grid { grid-template-columns: 1fr; gap: 40px; }
}

.about-image {
  aspect-ratio: 4/5;
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 16px;
  overflow: hidden;
  position: relative;
  display: grid;
  place-items: center;
}

.about-image::before {
  content: '老师';
  font-family: var(--font-zh);
  font-size: 200px;
  font-weight: 700;
  color: rgba(245, 245, 242, 0.04);
  position: absolute;
}

.about-image .placeholder-note {
  position: relative;
  color: var(--text-muted);
  font-size: 13px;
  text-align: center;
  z-index: 1;
}

.about-image img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  filter: grayscale(15%);
}

.about-text h2 {
  font-family: var(--font-display);
  font-size: clamp(36px, 4.5vw, 56px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin-bottom: 32px;
  font-weight: 400;
}

.about-text h2 em { font-style: italic; color: var(--accent); }

.about-text p {
  font-size: 17px;
  color: var(--text-dim);
  margin-bottom: 20px;
  line-height: 1.65;
}

.about-text p strong { color: var(--text); font-weight: 500; }

.credentials {
  margin-top: 48px;
  padding-top: 32px;
  border-top: 1px solid var(--border);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 24px;
}

.credential .label {
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.credential .value {
  font-family: var(--font-display);
  font-size: 18px;
  letter-spacing: -0.005em;
}

/* ---------- Audience strip ---------- */
.audience-row {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.audience-item {
  padding: 32px 24px;
  border-right: 1px solid var(--border);
  position: relative;
}

.audience-item:last-child { border-right: none; }

.audience-item .age {
  font-family: var(--font-zh);
  font-size: 13px;
  color: var(--accent);
  margin-bottom: 8px;
  letter-spacing: 0.05em;
}

.audience-item h4 {
  font-family: var(--font-display);
  font-size: 22px;
  font-weight: 400;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.audience-item p {
  font-size: 14px;
  color: var(--text-dim);
}

/* ---------- CTA strip ---------- */
.cta-strip {
  background:
    radial-gradient(ellipse at 30% 50%, rgba(232, 71, 44, 0.12), transparent 60%),
    var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: clamp(48px, 8vw, 96px);
  text-align: center;
  position: relative;
  overflow: hidden;
}

.cta-strip::before {
  content: '汉语';
  position: absolute;
  font-family: var(--font-zh);
  font-size: 280px;
  font-weight: 700;
  color: rgba(245, 245, 242, 0.025);
  bottom: -80px;
  right: -40px;
  user-select: none;
}

.cta-strip h2 {
  font-family: var(--font-display);
  font-size: clamp(32px, 5vw, 56px);
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin-bottom: 20px;
  font-weight: 400;
  position: relative;
}

.cta-strip h2 em { color: var(--accent); font-style: italic; }

.cta-strip p {
  font-size: 18px;
  color: var(--text-dim);
  max-width: 50ch;
  margin: 0 auto 32px;
  position: relative;
}

.cta-strip .btn { position: relative; }

/* ---------- Contact form ---------- */
.contact-grid {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: 80px;
  align-items: start;
}

@media (max-width: 800px) {
  .contact-grid { grid-template-columns: 1fr; gap: 40px; }
}

.contact-info h2 {
  font-family: var(--font-display);
  font-size: clamp(36px, 5vw, 56px);
  line-height: 1.05;
  letter-spacing: -0.02em;
  margin-bottom: 24px;
  font-weight: 400;
}

.contact-info h2 em { color: var(--accent); font-style: italic; }

.contact-info > p {
  font-size: 17px;
  color: var(--text-dim);
  margin-bottom: 40px;
  line-height: 1.6;
}

.contact-detail {
  padding: 20px 0;
  border-top: 1px solid var(--border);
}

.contact-detail:last-child { border-bottom: 1px solid var(--border); }

.contact-detail .label {
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 6px;
}

.contact-detail .value {
  font-family: var(--font-display);
  font-size: 22px;
  letter-spacing: -0.01em;
}

.contact-detail .value .zh {
  font-family: var(--font-zh);
  font-size: 0.8em;
  color: var(--accent);
  margin-right: 10px;
}

.contact-form {
  background: var(--bg-elev);
  border: 1px solid var(--border);
  border-radius: 20px;
  padding: 40px;
}

.form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

@media (max-width: 600px) {
  .form-row { grid-template-columns: 1fr; }
  .contact-form { padding: 28px; }
}

.form-field {
  margin-bottom: 20px;
}

.form-field label {
  display: block;
  font-size: 12px;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 8px;
}

.form-field input,
.form-field select,
.form-field textarea {
  width: 100%;
  padding: 14px 16px;
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text);
  font-family: inherit;
  font-size: 15px;
  transition: border-color 0.2s ease;
}

.form-field input:focus,
.form-field select:focus,
.form-field textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-soft);
}

.form-field textarea {
  resize: vertical;
  min-height: 120px;
}

/* ---------- Footer ---------- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 64px 0 32px;
  margin-top: 80px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr 1fr;
  gap: 48px;
  margin-bottom: 48px;
}

@media (max-width: 700px) {
  .footer-grid { grid-template-columns: 1fr 1fr; }
}

.footer-brand .logo { margin-bottom: 20px; }
.footer-brand p {
  font-size: 14px;
  color: var(--text-dim);
  max-width: 32ch;
  line-height: 1.6;
}

.footer-col h4 {
  font-size: 12px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--text-muted);
  margin-bottom: 16px;
  font-weight: 500;
}

.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 10px; }
.footer-col a {
  font-size: 14px;
  color: var(--text-dim);
  transition: color 0.2s ease;
}
.footer-col a:hover { color: var(--text); }

.footer-bottom {
  padding-top: 24px;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 13px;
  color: var(--text-muted);
  flex-wrap: wrap;
  gap: 12px;
}

.footer-bottom .zh {
  font-family: var(--font-zh);
  color: var(--text-dim);
}

/* ---------- Page Hero (smaller, for non-home pages) ---------- */
.page-hero {
  padding: clamp(60px, 10vw, 120px) 0 clamp(40px, 6vw, 80px);
  border-bottom: 1px solid var(--border);
  position: relative;
  overflow: hidden;
}

.page-hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 600px 200px at 30% 100%, rgba(232, 71, 44, 0.08), transparent 60%);
  pointer-events: none;
}

.page-hero h1 {
  font-family: var(--font-display);
  font-size: clamp(48px, 7vw, 88px);
  line-height: 1;
  letter-spacing: -0.025em;
  font-weight: 400;
  max-width: 14ch;
  position: relative;
}

.page-hero h1 em { color: var(--accent); font-style: italic; }
.page-hero h1 .zh { font-family: var(--font-zh); color: var(--accent); font-weight: 600; font-size: 0.85em; margin-right: 12px; }

.page-hero p {
  margin-top: 24px;
  font-size: 19px;
  color: var(--text-dim);
  max-width: 60ch;
  position: relative;
}

/* ---------- Mobile nav helpers ---------- */
@media (max-width: 700px) {
  .nav { display: none; }
  .header-cta-mobile { display: inline-flex; }
}

/* ---------- Reveal animations ---------- */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

.fade-up {
  animation: fadeUp 0.8s cubic-bezier(0.2, 0.8, 0.2, 1) both;
}

.fade-up:nth-child(2) { animation-delay: 0.1s; }
.fade-up:nth-child(3) { animation-delay: 0.2s; }
.fade-up:nth-child(4) { animation-delay: 0.3s; }