/* ================================================
   Talkpad — Shared Stylesheet
   Inspired by chatgpt.com: clean, minimal, spacious
   Primary: #1D2334 | Accent: #FFC574
   ================================================ */

:root {
  --color-text: #1D2334;
  --color-text-muted: #6B7280;
  --color-accent: #FFC574;
  --color-bg: #FFFFFF;
  --color-bg-subtle: #F7F7F5;
  --color-border: #E5E7EB;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --radius: 12px;
  --radius-sm: 8px;
  --max-width: 1100px;
  --transition: 0.2s ease;
}

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

html { font-size: 16px; scroll-behavior: smooth; }

body {
  font-family: var(--font);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

/* ── Layout ── */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Nav ── */
nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255,255,255,0.9);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--color-border);
}

.nav-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 1.05rem;
  letter-spacing: -0.01em;
}

.nav-logo svg { width: 28px; height: 28px; }

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  transition: color var(--transition);
}
.nav-links a:hover { color: var(--color-text); }

.btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 10px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-weight: 500;
  cursor: pointer;
  transition: all var(--transition);
  border: none;
}

.btn-primary {
  background: var(--color-text);
  color: #fff;
}
.btn-primary:hover { background: #2d3748; transform: translateY(-1px); }

.btn-accent {
  background: var(--color-accent);
  color: var(--color-text);
}
.btn-accent:hover { background: #f5b95a; transform: translateY(-1px); }

.btn-outline {
  background: transparent;
  color: var(--color-text);
  border: 1.5px solid var(--color-border);
}
.btn-outline:hover { border-color: var(--color-text); }

/* ── Hero ── */
.hero {
  padding: 100px 0 80px;
  text-align: center;
}

.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  font-size: 0.82rem;
  color: var(--color-text-muted);
  margin-bottom: 32px;
}

.hero-badge span { color: var(--color-accent); font-size: 1rem; }

.hero h1 {
  font-size: clamp(2.4rem, 5vw, 3.8rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  line-height: 1.15;
  max-width: 720px;
  margin: 0 auto 20px;
}

.hero h1 em {
  font-style: normal;
  position: relative;
  white-space: nowrap;
}

.hero h1 em::after {
  content: '';
  position: absolute;
  left: 0; right: 0; bottom: 2px;
  height: 4px;
  background: var(--color-accent);
  border-radius: 2px;
  opacity: 0.6;
}

.hero p {
  font-size: 1.15rem;
  color: var(--color-text-muted);
  max-width: 520px;
  margin: 0 auto 40px;
  line-height: 1.7;
}

.hero-cta {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.hero-note {
  margin-top: 16px;
  font-size: 0.82rem;
  color: var(--color-text-muted);
}

/* ── App Preview ── */
.app-preview {
  margin: 60px auto 0;
  max-width: 480px;
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: 16px;
  padding: 32px;
  text-align: center;
}

.waveform-demo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 4px;
  height: 56px;
  margin-bottom: 16px;
}

.waveform-demo span {
  display: block;
  width: 4px;
  background: var(--color-text);
  border-radius: 2px;
  animation: wave 1.2s ease-in-out infinite;
}

.waveform-demo span:nth-child(1) { height: 16px; animation-delay: 0s; }
.waveform-demo span:nth-child(2) { height: 32px; animation-delay: 0.1s; }
.waveform-demo span:nth-child(3) { height: 48px; animation-delay: 0.2s; }
.waveform-demo span:nth-child(4) { height: 36px; animation-delay: 0.3s; }
.waveform-demo span:nth-child(5) { height: 24px; animation-delay: 0.4s; }
.waveform-demo span:nth-child(6) { height: 40px; animation-delay: 0.3s; }
.waveform-demo span:nth-child(7) { height: 28px; animation-delay: 0.2s; }
.waveform-demo span:nth-child(8) { height: 16px; animation-delay: 0.1s; }

@keyframes wave {
  0%, 100% { transform: scaleY(1); opacity: 0.4; }
  50% { transform: scaleY(1.4); opacity: 1; }
}

.preview-text {
  font-size: 0.9rem;
  color: var(--color-text-muted);
}
.preview-text strong { color: var(--color-text); }

/* ── Section ── */
section { padding: 80px 0; }
section + section { border-top: 1px solid var(--color-border); }

.section-label {
  font-size: 0.78rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.25;
  margin-bottom: 16px;
}

.section-sub {
  font-size: 1.05rem;
  color: var(--color-text-muted);
  max-width: 540px;
  line-height: 1.7;
}

/* ── Features ── */
.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 24px;
  margin-top: 48px;
}

.feature-card {
  padding: 28px;
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-bg);
  transition: box-shadow var(--transition), transform var(--transition);
}

.feature-card:hover {
  box-shadow: 0 4px 24px rgba(0,0,0,0.06);
  transform: translateY(-2px);
}

.feature-icon {
  width: 44px;
  height: 44px;
  border-radius: var(--radius-sm);
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  margin-bottom: 18px;
}

.feature-icon svg,
.feature-icon i {
  width: 20px;
  height: 20px;
  stroke-width: 1.75;
}

.feature-card h3 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.feature-card p {
  font-size: 0.9rem;
  color: var(--color-text-muted);
  line-height: 1.65;
}

/* ── How it works ── */
.steps {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: 0;
  margin-top: 48px;
  position: relative;
}

.steps::before {
  content: '';
  position: absolute;
  top: 28px;
  left: calc(16.66% + 20px);
  right: calc(16.66% + 20px);
  height: 1px;
  background: var(--color-border);
}

.step {
  text-align: center;
  padding: 0 24px;
  position: relative;
}

.step-num {
  width: 56px;
  height: 56px;
  border-radius: 50%;
  background: white;
  border: 1px solid var(--color-border);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.3rem;
  margin: 0 auto 20px;
  position: relative;
  z-index: 1;
}

.step-num svg,
.step-num i {
  width: 22px;
  height: 22px;
  stroke-width: 1.75;
}

.step h3 {
  font-size: 0.95rem;
  font-weight: 600;
  margin-bottom: 8px;
}

.step p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ── Stats ── */
.stats {
  background: var(--color-bg-subtle);
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
  gap: 1px;
  background: var(--color-border);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  margin-top: 48px;
}

.stat {
  background: var(--color-bg-subtle);
  padding: 36px 28px;
  text-align: center;
}

.stat-value {
  font-size: 2.4rem;
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--color-text);
  line-height: 1;
  margin-bottom: 8px;
}

.stat-value em {
  font-style: normal;
  color: var(--color-accent);
}

.stat-label {
  font-size: 0.85rem;
  color: var(--color-text-muted);
}

/* ── CTA Banner ── */
.cta-banner {
  text-align: center;
  background: var(--color-text);
  color: white;
  padding: 80px 0;
  border-top: none;
}

.cta-banner .section-title { color: white; }

.cta-banner .section-sub {
  color: rgba(255,255,255,0.6);
  margin: 0 auto 40px;
}

/* ── Footer ── */
footer {
  background: var(--color-bg-subtle);
  border-top: 1px solid var(--color-border);
  padding: 40px 0;
}

.footer-inner {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 0.95rem;
}

.footer-links {
  display: flex;
  gap: 24px;
  list-style: none;
}

.footer-links a {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  transition: color var(--transition);
}
.footer-links a:hover { color: var(--color-text); }

.footer-copy {
  font-size: 0.82rem;
  color: var(--color-text-muted);
  width: 100%;
  text-align: center;
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--color-border);
}

/* ── Blog ── */
.blog-hero {
  padding: 72px 0 48px;
  border-bottom: 1px solid var(--color-border);
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 28px;
  margin-top: 48px;
}

.blog-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  overflow: hidden;
  transition: box-shadow var(--transition), transform var(--transition);
}

.blog-card:hover {
  box-shadow: 0 4px 24px rgba(0,0,0,0.07);
  transform: translateY(-2px);
}

.blog-card-thumb {
  height: 160px;
  background: var(--color-bg-subtle);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 3rem;
  border-bottom: 1px solid var(--color-border);
}

.blog-card-body { padding: 24px; }

.blog-tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--color-text-muted);
  margin-bottom: 10px;
}

.blog-card h2 {
  font-size: 1.05rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  line-height: 1.4;
  margin-bottom: 10px;
}

.blog-card p {
  font-size: 0.88rem;
  color: var(--color-text-muted);
  line-height: 1.65;
  margin-bottom: 16px;
}

.blog-meta {
  font-size: 0.8rem;
  color: var(--color-text-muted);
}

/* ── Article ── */
.article-header {
  padding: 72px 0 48px;
  border-bottom: 1px solid var(--color-border);
  max-width: 720px;
}

.article-body {
  max-width: 720px;
  margin: 0 auto;
  padding: 56px 24px 80px;
}

.article-body h2 {
  font-size: 1.4rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin: 48px 0 16px;
}

.article-body h3 {
  font-size: 1.1rem;
  font-weight: 600;
  margin: 32px 0 12px;
}

.article-body p {
  margin-bottom: 20px;
  line-height: 1.8;
  font-size: 1.02rem;
  color: #2d3748;
}

.article-body ul, .article-body ol {
  margin: 0 0 20px 24px;
  line-height: 1.8;
  font-size: 1.02rem;
  color: #2d3748;
}

.article-body li { margin-bottom: 6px; }

.article-body strong { color: var(--color-text); font-weight: 600; }

.article-body blockquote {
  border-left: 3px solid var(--color-accent);
  padding: 12px 20px;
  margin: 28px 0;
  background: var(--color-bg-subtle);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-style: italic;
  color: var(--color-text-muted);
}

.article-table {
  width: 100%;
  border-collapse: collapse;
  margin: 28px 0;
  font-size: 0.9rem;
}

.article-table th {
  text-align: left;
  padding: 12px 16px;
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  font-weight: 600;
}

.article-table td {
  padding: 12px 16px;
  border: 1px solid var(--color-border);
  color: var(--color-text-muted);
}

.article-table td:first-child { color: var(--color-text); font-weight: 500; }

.highlight { background: rgba(255, 197, 116, 0.2); padding: 2px 4px; border-radius: 3px; }

.article-cta {
  margin-top: 56px;
  padding: 32px;
  background: var(--color-bg-subtle);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  text-align: center;
}

.article-cta h3 { font-size: 1.2rem; margin-bottom: 8px; }
.article-cta p { color: var(--color-text-muted); margin-bottom: 20px; font-size: 0.95rem; }

/* ── Responsive ── */
@media (max-width: 768px) {
  .nav-links { display: none; }
  .steps::before { display: none; }
  .steps { gap: 32px; }
  .footer-inner { flex-direction: column; align-items: flex-start; }
  .article-header { padding: 48px 0 32px; }
}