/* ── AlphaFei Global Styles ── */
:root {
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: #1a1a25;
  --bg-card-hover: #22222f;
  --accent-green: #00e676;
  --accent-gold: #d4af37;
  --accent-gold-light: #f0d060;
  --text-primary: #f0f0f5;
  --text-secondary: #a0a0b0;
  --text-muted: #666680;
  --border-color: #2a2a3a;
  --gradient-hero: linear-gradient(135deg, #0a0a0f 0%, #0d1a0d 50%, #0a0a0f 100%);
  --gradient-accent: linear-gradient(135deg, var(--accent-green), var(--accent-gold));
  --shadow-glow: 0 0 30px rgba(0, 230, 118, 0.15);
  --radius: 12px;
  --radius-lg: 20px;
  --max-width: 1100px;
  --transition: 0.3s ease;
}

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

html { scroll-behavior: smooth; }

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Noto Sans TC", "Microsoft JhengHei", sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.7;
  -webkit-font-smoothing: antialiased;
}

a { color: var(--accent-green); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--accent-gold-light); }

img { max-width: 100%; height: auto; }

/* ── Navigation ── */
.nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(10, 10, 15, 0.85);
  backdrop-filter: blur(20px);
  border-bottom: 1px solid var(--border-color);
  padding: 0 24px;
}
.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.nav-logo {
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: 0.02em;
}
.nav-logo span {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.nav-links { display: flex; gap: 24px; align-items: center; }
.nav-links a {
  color: var(--text-secondary);
  font-size: 0.9rem;
  transition: color var(--transition);
}
.nav-links a:hover { color: var(--text-primary); }

/* ── Buttons ── */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  padding: 14px 32px;
  border-radius: 50px;
  font-size: 1.05rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
  text-decoration: none;
}
.btn-primary {
  background: var(--gradient-accent);
  color: #0a0a0f;
  box-shadow: var(--shadow-glow);
}
.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 0 40px rgba(0, 230, 118, 0.3);
  color: #0a0a0f;
}
.btn-outline {
  background: transparent;
  color: var(--accent-green);
  border: 2px solid var(--accent-green);
}
.btn-outline:hover {
  background: rgba(0, 230, 118, 0.1);
  color: var(--accent-green);
  transform: translateY(-2px);
}
.btn-sm { padding: 10px 24px; font-size: 0.9rem; }

/* ── Hero Section ── */
.hero {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  background: var(--gradient-hero);
  padding: 120px 24px 80px;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  width: 600px;
  height: 600px;
  background: radial-gradient(circle, rgba(0, 230, 118, 0.08) 0%, transparent 70%);
  pointer-events: none;
}
.hero-content { position: relative; z-index: 1; max-width: 700px; }
.hero-badge {
  display: inline-block;
  padding: 6px 18px;
  border-radius: 50px;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--accent-green);
  border: 1px solid rgba(0, 230, 118, 0.3);
  background: rgba(0, 230, 118, 0.06);
  margin-bottom: 28px;
  letter-spacing: 0.05em;
}
.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.4rem);
  font-weight: 800;
  line-height: 1.25;
  margin-bottom: 20px;
  letter-spacing: -0.02em;
}
.hero h1 .highlight {
  background: var(--gradient-accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}
.hero p {
  font-size: 1.15rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
  max-width: 550px;
  margin-left: auto;
  margin-right: auto;
}
.hero-buttons { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

/* ── Sections ── */
.section {
  padding: 100px 24px;
  max-width: var(--max-width);
  margin: 0 auto;
}
.section-label {
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.15em;
  color: var(--accent-green);
  margin-bottom: 12px;
}
.section-title {
  font-size: clamp(1.8rem, 3.5vw, 2.4rem);
  font-weight: 700;
  margin-bottom: 16px;
  letter-spacing: -0.01em;
}
.section-desc {
  font-size: 1.05rem;
  color: var(--text-secondary);
  max-width: 600px;
  margin-bottom: 48px;
}
.section-center { text-align: center; }
.section-center .section-desc { margin-left: auto; margin-right: auto; }

/* ── Course Cards Grid ── */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(300px, 1fr));
  gap: 20px;
}
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  padding: 32px 28px;
  transition: all var(--transition);
}
.card:hover {
  background: var(--bg-card-hover);
  border-color: rgba(0, 230, 118, 0.2);
  transform: translateY(-4px);
}
.card-img {
  width: 100%;
  height: 160px;
  object-fit: cover;
  border-radius: 8px;
  margin-bottom: 16px;
}
.card-number {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  border-radius: 10px;
  background: rgba(0, 230, 118, 0.1);
  color: var(--accent-green);
  font-weight: 700;
  font-size: 1rem;
  margin-bottom: 16px;
}
.card h3 {
  font-size: 1.15rem;
  font-weight: 600;
  margin-bottom: 8px;
}
.card p {
  font-size: 0.92rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ── Instructor Section ── */
.instructor {
  display: flex;
  gap: 48px;
  align-items: center;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-lg);
  padding: 48px;
}
.instructor-avatar-img {
  flex-shrink: 0;
  width: 160px;
  height: 160px;
  border-radius: 50%;
  object-fit: cover;
  border: 3px solid var(--accent-green);
  box-shadow: 0 0 20px rgba(0, 230, 118, 0.15);
}
.instructor-info h3 {
  font-size: 1.5rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.instructor-info .tag {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 50px;
  font-size: 0.8rem;
  background: rgba(212, 175, 55, 0.15);
  color: var(--accent-gold-light);
  margin-bottom: 16px;
}
.instructor-info p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* ── YouTube Embed ── */
.video-wrapper {
  position: relative;
  width: 100%;
  max-width: 800px;
  margin: 0 auto;
  border-radius: var(--radius-lg);
  overflow: hidden;
  border: 1px solid var(--border-color);
  box-shadow: var(--shadow-glow);
}
.video-wrapper::before {
  content: '';
  display: block;
  padding-top: 56.25%;
}
.video-wrapper iframe {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  border: none;
}

/* ── CTA Banner ── */
.cta-banner {
  text-align: center;
  padding: 80px 24px;
  background: linear-gradient(180deg, transparent 0%, rgba(0, 230, 118, 0.03) 50%, transparent 100%);
}
.cta-banner h2 {
  font-size: clamp(1.6rem, 3vw, 2rem);
  margin-bottom: 16px;
}
.cta-banner p {
  color: var(--text-secondary);
  margin-bottom: 32px;
  font-size: 1.05rem;
}

/* ── Footer ── */
.footer {
  border-top: 1px solid var(--border-color);
  padding: 48px 24px;
  text-align: center;
}
.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
}
.footer-socials {
  display: flex;
  justify-content: center;
  gap: 20px;
  margin-bottom: 24px;
}
.footer-socials a {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  font-size: 1.2rem;
  transition: all var(--transition);
}
.footer-socials a:hover {
  border-color: var(--accent-green);
  color: var(--accent-green);
  transform: translateY(-2px);
}
.footer-info { color: var(--text-muted); font-size: 0.82rem; line-height: 1.8; }
.footer-info a { color: var(--text-muted); }
.footer-info a:hover { color: var(--accent-green); }

/* ── Threads Tool ── */
.tool-container {
  max-width: 800px;
  margin: 0 auto;
  padding: 100px 24px 60px;
}
.tool-header {
  text-align: center;
  margin-bottom: 40px;
}
.tool-header h1 {
  font-size: 1.8rem;
  font-weight: 700;
  margin-bottom: 8px;
}
.tool-header p {
  color: var(--text-secondary);
  font-size: 0.95rem;
}
.tool-group {
  margin-bottom: 20px;
}
.tool-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-secondary);
  margin-bottom: 8px;
}
.tool-textarea {
  width: 100%;
  min-height: 200px;
  padding: 16px;
  background: #f5f5f7;
  border: 1px solid #d0d0d8;
  border-radius: var(--radius);
  color: #1a1a25;
  font-size: 0.95rem;
  font-family: inherit;
  line-height: 1.6;
  resize: vertical;
  transition: border-color var(--transition);
}
.tool-textarea:focus {
  outline: none;
  border-color: var(--accent-green);
  background: #fff;
}
.tool-textarea::placeholder { color: #999; }
.tool-options {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-bottom: 24px;
}
.tool-option {
  display: flex;
  align-items: center;
  gap: 10px;
  cursor: pointer;
}
.tool-option input[type="checkbox"] {
  appearance: none;
  -webkit-appearance: none;
  width: 20px;
  height: 20px;
  border: 2px solid var(--border-color);
  border-radius: 5px;
  background: var(--bg-card);
  cursor: pointer;
  position: relative;
  flex-shrink: 0;
  transition: all var(--transition);
}
.tool-option input[type="checkbox"]:checked {
  background: var(--accent-green);
  border-color: var(--accent-green);
}
.tool-option input[type="checkbox"]:checked::after {
  content: '✓';
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  color: #0a0a0f;
  font-size: 0.75rem;
  font-weight: 700;
}
.tool-option span {
  font-size: 0.9rem;
  color: var(--text-secondary);
}
.tool-input {
  width: 100%;
  padding: 12px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border-color);
  border-radius: var(--radius);
  color: var(--text-primary);
  font-size: 0.9rem;
  font-family: inherit;
  transition: border-color var(--transition);
}
.tool-input:focus {
  outline: none;
  border-color: var(--accent-green);
}
.tool-buttons {
  display: flex;
  gap: 12px;
  margin-bottom: 24px;
  flex-wrap: wrap;
}
.tool-buttons .btn { flex: 1; justify-content: center; min-width: 140px; }
.tool-result-label {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 8px;
}
.char-count {
  font-size: 0.82rem;
  color: var(--text-muted);
}
.toast {
  position: fixed;
  bottom: 32px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--accent-green);
  color: #0a0a0f;
  padding: 12px 28px;
  border-radius: 50px;
  font-weight: 600;
  font-size: 0.9rem;
  opacity: 0;
  transition: all 0.4s ease;
  z-index: 999;
  pointer-events: none;
}
.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* ── Responsive ── */
@media (max-width: 768px) {
  .instructor {
    flex-direction: column;
    text-align: center;
    padding: 32px 24px;
    gap: 24px;
  }
  .instructor-avatar { width: 120px; height: 120px; font-size: 2.5rem; }
  .section { padding: 60px 20px; }
  .cards-grid { grid-template-columns: 1fr; }
  .nav-links { display: none; }
  .hero { padding: 100px 20px 60px; }
  .hero-buttons { flex-direction: column; align-items: center; }
  .tool-buttons { flex-direction: column; }
  .tool-buttons .btn { min-width: auto; }
}