/* ================================
   TezTok Landing — style.css
   Simple, clean, no fluff.
   ================================ */

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

:root {
  --accent:  #e8354a;
  --bg:      #ffffff;
  --bg2:     #f7f7f7;
  --text:    #111111;
  --text2:   #555555;
  --text3:   #999999;
  --border:  #e4e4e4;
  --font:    'Inter', system-ui, sans-serif;
  --radius:  10px;
}

html { scroll-behavior: smooth; }

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

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

/* ── Container ─────────────────────────────────── */
.container {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
}

/* ── Navigation ────────────────────────────────── */
.nav {
  position: fixed;
  top: 0; left: 0; right: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
}

.nav-inner {
  max-width: 1100px;
  margin: 0 auto;
  padding: 0 24px;
  height: 60px;
  display: flex;
  align-items: center;
  gap: 40px;
}

.nav-logo {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  flex-shrink: 0;
}

.logo-tez, .logo-tok { color: var(--text); }

.nav-links {
  display: flex;
  list-style: none;
  gap: 28px;
  flex: 1;
}

.nav-links a {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text2);
  transition: color 0.15s;
}

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

.nav-cta {
  font-size: 0.875rem;
  font-weight: 600;
  padding: 8px 18px;
  background: var(--text);
  color: #fff;
  border-radius: 6px;
  white-space: nowrap;
  flex-shrink: 0;
  transition: opacity 0.15s;
}

.nav-cta:hover { opacity: 0.8; }

.lang-switcher {
  display: flex;
  align-items: center;
}
.lang-select {
  background: var(--bg2);
  color: var(--text2);
  border: 1px solid var(--border);
  border-radius: 100px;
  padding: 6px 12px;
  padding-right: 32px;
  font-size: 0.8rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml;charset=UTF-8,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%23555555' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'%3e%3cpolyline points='6 9 12 15 18 9'%3e%3c/polyline%3e%3c/svg%3e");
  background-repeat: no-repeat;
  background-position: right 12px center;
  background-size: 14px;
}
.lang-select:focus {
  outline: none;
  border-color: var(--text3);
}

/* ── Hero ──────────────────────────────────────── */
.hero {
  min-height: 100vh;
  padding: 100px 24px 80px;
  max-width: 1100px;
  margin: 0 auto;
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: 80px;
}

.hero-content {
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.hero-kicker {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--accent);
}

.hero-title {
  font-size: clamp(2.4rem, 4.5vw, 3.8rem);
  font-weight: 800;
  line-height: 1.06;
  letter-spacing: -0.04em;
}

.hero-subtitle {
  font-size: 1rem;
  color: var(--text2);
  line-height: 1.75;
  max-width: 460px;
}

.hero-actions {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  background: var(--text);
  color: #fff;
  font-size: 0.925rem;
  font-weight: 600;
  border-radius: 6px;
  transition: opacity 0.15s;
}

.btn-primary:hover { opacity: 0.8; }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 12px 24px;
  color: var(--text);
  font-size: 0.925rem;
  font-weight: 600;
  border-radius: 6px;
  border: 1px solid var(--border);
  transition: border-color 0.15s;
}

.btn-secondary:hover { border-color: #bbb; }

/* Hero phones */
.hero-phones {
  display: flex;
  justify-content: center;
  align-items: center;
}

.phone-stack {
  position: relative;
  width: 280px;
  height: 560px;
}

.phone {
  position: absolute;
  width: 240px;
  border-radius: 40px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: #fff;
}

.phone-back {
  right: -20px;
  top: 40px;
  transform: rotate(5deg) scale(0.9);
  z-index: 1;
  opacity: 0.5;
}

.phone-front {
  left: 0;
  top: 0;
  z-index: 2;
  box-shadow: 0 20px 60px rgba(0,0,0,0.12);
}

.phone-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top;
}

/* ── Sections shared ───────────────────────────── */
section { padding: 100px 0; }

.section-header {
  margin-bottom: 60px;
}

.section-label {
  display: block;
  font-size: 0.75rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(1.8rem, 3.5vw, 2.6rem);
  font-weight: 800;
  line-height: 1.1;
  letter-spacing: -0.03em;
  margin-bottom: 16px;
}

.section-desc {
  font-size: 0.975rem;
  color: var(--text2);
  max-width: 520px;
  line-height: 1.75;
}

/* ── Features ──────────────────────────────────── */
.features { background: var(--bg); border-top: 1px solid var(--border); }

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.feature-card {
  background: var(--bg);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.feature-card--wide {
  grid-column: span 2;
}

.feature-title {
  font-size: 1rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.feature-desc {
  font-size: 0.875rem;
  color: var(--text2);
  line-height: 1.7;
}

.source-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 8px;
}

.source-chip {
  font-size: 0.75rem;
  font-weight: 500;
  padding: 3px 10px;
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: 100px;
  color: var(--text2);
}

/* ── Showcase ──────────────────────────────────── */
.showcase { background: var(--bg2); border-top: 1px solid var(--border); }

.showcase-tabs {
  display: flex;
  gap: 4px;
  margin-bottom: 48px;
  border-bottom: 1px solid var(--border);
  padding-bottom: 0;
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
  scrollbar-width: none;
}
.showcase-tabs::-webkit-scrollbar {
  display: none;
}

.tab {
  padding: 10px 18px;
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  margin-bottom: -1px;
  white-space: nowrap;
  color: var(--text2);
  font-family: var(--font);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: color 0.15s, border-color 0.15s;
}

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

.tab.active {
  color: var(--text);
  font-weight: 600;
  border-bottom-color: var(--text);
}

.showcase-panel {
  display: none;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: 72px;
  padding: 8px 0;
}

.showcase-panel.active {
  display: grid;
}

/* Panel phones */
.panel-phones {
  position: relative;
  height: 540px;
}

.panel-phone {
  border-radius: 36px;
  overflow: hidden;
  border: 1px solid var(--border);
  background: #fff;
  position: absolute;
}

.panel-phone--primary {
  width: 230px;
  height: 500px;
  z-index: 2;
  left: 50%;
  top: 50%;
  transform: translate(-60%, -50%);
  box-shadow: 0 16px 48px rgba(0,0,0,0.1);
}

.panel-phone--secondary {
  width: 190px;
  height: 420px;
  z-index: 1;
  left: 50%;
  top: 50%;
  transform: translate(8%, -50%) rotate(5deg);
  opacity: 0.5;
}

.panel-phone--solo {
  width: 250px;
  height: 540px;
  left: 50%;
  top: 50%;
  transform: translate(-50%, -50%);
}

.panel-phone-img {
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: top;
}

/* Panel info */
.panel-info {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.panel-title {
  font-size: 1.5rem;
  font-weight: 800;
  letter-spacing: -0.03em;
}

.panel-desc {
  font-size: 0.9rem;
  color: var(--text2);
  line-height: 1.75;
}

.panel-bullets {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 8px;
  border-top: 1px solid var(--border);
  padding-top: 16px;
  margin-top: 4px;
}

.panel-bullets li {
  font-size: 0.875rem;
  color: var(--text2);
  padding-left: 14px;
  position: relative;
}

.panel-bullets li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--accent);
}

/* ── Sources section ───────────────────────────── */
.sources-section {
  background: var(--bg);
  border-top: 1px solid var(--border);
}

.sources-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.source-card {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 22px 24px;
  background: var(--bg);
}

.source-logo-mark {
  width: 40px; height: 40px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 800;
  flex-shrink: 0;
  color: #fff;
}

.source-logo-mark--yoktez  { background: #c0392b; }
.source-logo-mark--openalex{ background: #2563eb; }
.source-logo-mark--semantic{ background: #7c3aed; }
.source-logo-mark--arxiv   { background: #d97706; }
.source-logo-mark--core    { background: #059669; }
.source-logo-mark--crossref{ background: #4f46e5; }

.source-info {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.source-name {
  font-size: 0.9rem;
  font-weight: 600;
}

.source-detail {
  font-size: 0.78rem;
  color: var(--text3);
  line-height: 1.4;
}

.source-req {
  display: inline-block;
  width: fit-content;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 4px;
  background: #fff8e6;
  color: #92600a;
  border: 1px solid #f0d080;
  margin-top: 4px;
  cursor: default;
}

/* Tooltip injected by JS into <body> */
.req-tooltip {
  position: fixed;
  z-index: 9999;
  background: #111;
  color: #fff;
  font-size: 0.75rem;
  line-height: 1.55;
  padding: 8px 12px;
  border-radius: 6px;
  max-width: 220px;
  pointer-events: none;
  opacity: 0;
  transition: opacity 0.15s;
  white-space: normal;
}

/* ── Why This Matters ──────────────────────────── */
.why-section {
  background: var(--bg2);
  border-top: 1px solid var(--border);
}

.why-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--border);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.why-card {
  background: var(--bg);
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 14px;
}

.why-title {
  font-size: 0.95rem;
  font-weight: 700;
}

.why-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.why-list li {
  font-size: 0.875rem;
  color: var(--text2);
  line-height: 1.7;
  padding-left: 14px;
  position: relative;
}

.why-list li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--accent);
}

.why-list li strong {
  color: var(--text);
  font-weight: 600;
}

/* ── Evaluation ────────────────────────────────── */
.evaluation-section {
  background: var(--bg);
  border-top: 1px solid var(--border);
}

.eval-grid {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.eval-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.eval-label {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--text3);
}

.eval-text {
  font-size: 0.9rem;
  color: var(--text2);
  line-height: 1.75;
}

.eval-caveat {
  font-size: 0.8rem;
  color: var(--text3);
  line-height: 1.6;
  border-top: 1px solid var(--border);
  padding-top: 12px;
}

.eval-cards-row {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 16px;
}

.eval-stat-card {
  background: var(--bg2);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 8px;
}

.eval-stat-number {
  font-size: 2.4rem;
  font-weight: 800;
  letter-spacing: -0.04em;
  color: var(--text);
}

.eval-stat-label {
  font-size: 0.8rem;
  color: var(--text2);
  line-height: 1.4;
}

/* ── Download CTA ──────────────────────────────── */
.download {
  background: var(--bg2);
  border-top: 1px solid var(--border);
  padding: 100px 0;
}

.download-content {
  max-width: 560px;
}

.download-title {
  font-size: clamp(1.8rem, 3vw, 2.4rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  margin-bottom: 12px;
}

.download-desc {
  font-size: 0.975rem;
  color: var(--text2);
  line-height: 1.7;
  margin-bottom: 28px;
}

.download-options {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  margin-bottom: 24px;
}

.download-stack {
  font-size: 0.8rem;
  color: var(--text3);
}

/* ── Footer ────────────────────────────────────── */
.footer {
  background: var(--bg);
  border-top: 1px solid var(--border);
  padding: 48px 0;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.footer-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 2px;
}

.footer-lang {
  display: none;
}

.footer-logo {
  font-size: 1.1rem;
  font-weight: 800;
  letter-spacing: -0.03em;
}

.footer-tagline {
  font-size: 0.875rem;
  color: var(--text2);
}

.footer-note {
  font-size: 0.8rem;
  color: var(--text3);
  max-width: 480px;
  line-height: 1.6;
}

/* ── Responsive ────────────────────────────────── */
@media (max-width: 960px) {
  .hero {
    grid-template-columns: 1fr;
    gap: 60px;
    padding-bottom: 80px;
    min-height: auto;
    padding-top: 100px;
  }

  .hero-phones { justify-content: flex-start; }

  .features-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .feature-card--wide { grid-column: span 2; }

  .showcase-panel.active { grid-template-columns: 1fr; }
  .panel-phones { height: 460px; }

  .sources-grid { grid-template-columns: repeat(2, 1fr); }
  .why-grid { grid-template-columns: 1fr; }
}

@media (max-width: 640px) {
  section { padding: 72px 0; }

  .nav-links { display: none; }
  .nav-cta { display: none; }
  .header-lang { display: none !important; }
  .footer-lang { display: flex; }
  .nav-inner { justify-content: center; }
  .features-grid { grid-template-columns: 1fr; }
  .feature-card--wide { grid-column: span 1; }

  .eval-cards-row { grid-template-columns: 1fr; }

  .panel-phones { height: 400px; }
  .panel-phone--primary { width: 200px; height: 440px; transform: translate(-55%, -50%); }
  .panel-phone--secondary { width: 160px; height: 360px; transform: translate(12%, -50%) rotate(5deg); }
  .panel-phone--solo { width: 210px; height: 460px; }

  .sources-grid { grid-template-columns: 1fr; }
  .why-grid { grid-template-columns: 1fr; }

  .hero-title { font-size: 2.2rem; }
}