/* Thiup landing — vanilla CSS.
   Tokens mirror the app design system (frontend CLAUDE.md): warm paper palette,
   Inter, 8px radius, sober/warm tone. Pure #FFFFFF is forbidden. */

@font-face {
  font-family: "Inter";
  src: url("assets/fonts/InterVariable.woff2") format("woff2");
  font-weight: 100 900;
  font-style: normal;
  font-display: swap;
}

:root {
  /* Surfaces */
  --bg: #f7f5f0;
  --surface: #fdfcf8;
  --hover: #f0ece3;
  --tint: #f3e3d3;
  /* Text */
  --text: #1a1a1a;
  --text-2: #6b6b6b;
  --text-3: #a3a3a3;
  /* Borders */
  --border: #e5e0d3;
  --border-soft: #ebe7dd;
  /* Brand */
  --accent: #a85432;
  --accent-ink: #8b6f47;
  /* Shape */
  --radius: 8px;
  --radius-btn: 12px;
  --maxw: 1080px;
  --shadow-card: 0 4px 20px rgba(26, 26, 26, 0.06);
  --shadow-pop: 0 8px 24px rgba(26, 26, 26, 0.08);
  --ring: inset 0 0 0 2px #c5a572;
  --font: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", system-ui,
    Roboto, Helvetica, Arial, sans-serif;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  color: var(--text);
  background: var(--bg);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

h1,
h2,
h3,
p {
  margin: 0;
}

a {
  color: inherit;
  text-decoration: none;
}

.container {
  width: 100%;
  max-width: var(--maxw);
  margin: 0 auto;
  padding: 0 24px;
}

/* ===== Accessibility ===== */

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  z-index: 100;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 8px 14px;
  font-size: 14px;
}

.skip-link:focus {
  left: 16px;
  top: 16px;
}

:focus-visible {
  outline: none;
  box-shadow: var(--ring);
  border-radius: var(--radius);
}

/* ===== Buttons ===== */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  min-height: 44px;
  padding: 11px 20px;
  border: 1px solid transparent;
  border-radius: var(--radius-btn);
  font-family: inherit;
  font-size: 15px;
  font-weight: 600;
  line-height: 1;
  cursor: pointer;
  transition: opacity 140ms ease, background 140ms ease, border-color 140ms ease,
    transform 140ms ease, box-shadow 140ms ease;
}

/* Dark fill, cream text — the canonical Thiup primary button. */
.btn-primary {
  background: var(--text);
  color: var(--surface);
}

.btn-primary:hover {
  opacity: 0.9;
  transform: translateY(-1px);
  box-shadow: 0 6px 18px rgba(26, 26, 26, 0.14);
}

.btn-primary:active {
  transform: translateY(0);
}

.btn-ghost {
  background: transparent;
  border-color: var(--border);
  color: var(--text);
  font-size: 14px;
  min-height: 40px;
  padding: 9px 16px;
}

.btn-ghost:hover {
  background: var(--hover);
}

.btn-quiet {
  background: transparent;
  color: var(--text-2);
}

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

.btn svg {
  width: 18px;
  height: 18px;
  flex: none;
}

/* Icon-only header link (GitHub). */
.icon-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border-radius: 10px;
  color: var(--text-2);
  transition: background 140ms ease, color 140ms ease;
}

.icon-btn:hover {
  background: var(--hover);
  color: var(--text);
}

.icon-btn svg {
  width: 20px;
  height: 20px;
}

/* ===== Header ===== */

.site-header {
  position: sticky;
  top: 0;
  z-index: 20;
  background: rgba(247, 245, 240, 0.78);
  -webkit-backdrop-filter: blur(12px) saturate(180%);
  backdrop-filter: blur(12px) saturate(180%);
  border-bottom: 1px solid var(--border-soft);
  transition: box-shadow 200ms ease;
}

.site-header.scrolled {
  box-shadow: 0 6px 20px rgba(26, 26, 26, 0.05);
}

.hero-eyebrow {
  display: inline-block;
  margin-bottom: 22px;
  padding: 6px 14px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--accent-ink);
  font-size: 13px;
  font-weight: 600;
}

@supports not ((backdrop-filter: blur(1px)) or (-webkit-backdrop-filter: blur(1px))) {
  .site-header {
    background: var(--bg);
  }
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding-top: 12px;
  padding-bottom: 12px;
}

.brand {
  display: inline-flex;
  align-items: center;
  gap: 9px;
}

.brand-word {
  font-size: 18px;
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text);
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 22px;
  margin-left: 6px;
  margin-right: auto;
}

.header-nav a {
  color: var(--text-2);
  font-size: 14px;
  font-weight: 500;
  transition: color 140ms ease;
}

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

.header-nav a[aria-current="page"] {
  color: var(--text);
  font-weight: 600;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Language toggle (segmented) */
.lang-toggle {
  display: inline-flex;
  padding: 3px;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
}

.lang-btn {
  border: 0;
  background: transparent;
  color: var(--text-2);
  font-family: inherit;
  font-size: 12px;
  font-weight: 600;
  letter-spacing: 0.04em;
  padding: 5px 11px;
  border-radius: 999px;
  cursor: pointer;
  transition: background 140ms ease, color 140ms ease;
}

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

.lang-btn[aria-pressed="true"] {
  background: var(--tint);
  color: var(--accent);
}

/* ===== Hero ===== */

.hero {
  position: relative;
  overflow: hidden;
  text-align: center;
  padding: clamp(64px, 12vw, 132px) 0 clamp(56px, 9vw, 104px);
}

.hero-thread {
  position: absolute;
  left: 0;
  right: 0;
  top: 38%;
  width: 100%;
  height: 200px;
  opacity: 0.1;
  pointer-events: none;
}

.hero-inner {
  position: relative;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.hero-mark {
  margin-bottom: 28px;
  box-shadow: var(--shadow-card);
  border-radius: 17px;
}

.hero-title {
  font-size: clamp(2.2rem, 5.2vw, 3.4rem);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.02em;
  max-width: 16ch;
}

.hero-subtitle {
  margin-top: 18px;
  max-width: 52ch;
  font-size: clamp(1rem, 2vw, 1.18rem);
  line-height: 1.5;
  color: var(--text-2);
}

.hero-cta {
  margin-top: 32px;
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 12px;
}

/* ===== About / features ===== */

.about {
  background: var(--surface);
  border-top: 1px solid var(--border-soft);
  border-bottom: 1px solid var(--border-soft);
  padding: clamp(56px, 9vw, 100px) 0;
  text-align: center;
}

.section-title {
  font-size: clamp(1.6rem, 3.4vw, 2.1rem);
  font-weight: 700;
  letter-spacing: -0.01em;
}

.section-lead {
  margin: 14px auto 0;
  max-width: 50ch;
  color: var(--text-2);
  font-size: 1.05rem;
}

.features {
  list-style: none;
  margin: clamp(36px, 6vw, 56px) 0 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 18px;
  text-align: left;
}

.feature {
  background: var(--bg);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
}

.feature-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius);
  background: var(--tint);
  color: var(--accent);
  margin-bottom: 16px;
}

.feature-icon svg {
  width: 22px;
  height: 22px;
}

.feature-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 7px;
}

.feature-text {
  color: var(--text-2);
  font-size: 0.95rem;
  line-height: 1.5;
}

/* ===== How it works (in depth) ===== */

.deep {
  padding: clamp(56px, 9vw, 100px) 0;
  text-align: center;
}

.how-list {
  list-style: none;
  margin: clamp(36px, 6vw, 56px) auto 0;
  padding: 0;
  max-width: 880px;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 28px 32px;
  text-align: left;
}

.how-item {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 16px;
  align-items: start;
}

.how-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  border-radius: var(--radius);
  background: var(--tint);
  color: var(--accent);
}

.how-icon svg {
  width: 22px;
  height: 22px;
}

.how-title {
  font-size: 1.05rem;
  font-weight: 600;
  margin-bottom: 6px;
}

.how-text {
  color: var(--text-2);
  font-size: 0.95rem;
  line-height: 1.55;
}

.how-close {
  margin: clamp(32px, 5vw, 48px) auto 0;
  max-width: 62ch;
  color: var(--text-2);
  font-size: 1rem;
  line-height: 1.6;
}

/* Quiet "read more" link rows under a section's content. */
.section-links {
  margin-top: 20px;
  font-size: 14px;
}

.section-links a {
  color: var(--accent);
  font-weight: 500;
}

.section-links a:hover {
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ===== Subpages (/how-it-works, /open-source, /privacy) ===== */

.page {
  padding: clamp(48px, 8vw, 88px) 0 clamp(64px, 10vw, 112px);
}

.page-inner {
  max-width: 720px;
}

.page-title {
  font-size: clamp(1.9rem, 4.4vw, 2.7rem);
  font-weight: 700;
  line-height: 1.12;
  letter-spacing: -0.02em;
}

.page-lead {
  margin-top: 14px;
  color: var(--text-2);
  font-size: 1.1rem;
  line-height: 1.5;
}

.page h2 {
  margin: clamp(30px, 5vw, 44px) 0 10px;
  font-size: 1.25rem;
  font-weight: 700;
  letter-spacing: -0.01em;
}

.page p {
  color: var(--text-2);
  line-height: 1.65;
}

.page p + p {
  margin-top: 12px;
}

.page-cta {
  margin-top: clamp(30px, 5vw, 44px);
  color: var(--text);
  font-weight: 500;
}

.page .btn-primary {
  margin-top: 16px;
}

/* ===== Open source band ===== */

.open-source {
  background: var(--surface);
  border-top: 1px solid var(--border-soft);
  border-bottom: 1px solid var(--border-soft);
  padding: clamp(56px, 9vw, 96px) 0;
  text-align: center;
}

.os-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.os-inner .section-lead {
  max-width: 54ch;
}

.os-inner .btn {
  margin-top: 28px;
}

.os-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 56px;
  height: 56px;
  border-radius: 14px;
  background: var(--tint);
  color: var(--accent);
  margin-bottom: 20px;
}

.os-icon svg {
  width: 30px;
  height: 30px;
}

/* ===== Final CTA band ===== */

.cta-band {
  background: var(--tint);
  padding: clamp(56px, 9vw, 96px) 0;
  text-align: center;
}

.cta-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
}

.cta-title {
  font-size: clamp(1.7rem, 4vw, 2.4rem);
  font-weight: 700;
  letter-spacing: -0.01em;
  color: var(--text);
}

.cta-text {
  margin: 12px 0 28px;
  max-width: 44ch;
  color: var(--accent-ink);
  font-size: 1.05rem;
}

/* ===== Footer ===== */

.site-footer {
  background: var(--bg);
  border-top: 1px solid var(--border-soft);
  padding: 40px 0;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 10px;
  text-align: center;
}

.brand-sm .brand-word {
  font-size: 15px;
  font-weight: 600;
}

.footer-tagline {
  color: var(--text);
  font-weight: 500;
}

.footer-nav {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  align-items: center;
  gap: 10px;
}

.footer-nav a {
  color: var(--accent);
  font-size: 14px;
  font-weight: 500;
}

.footer-dot {
  color: #c4bfb1;
}

.footer-nav a:hover {
  text-decoration: underline;
  text-underline-offset: 2px;
}

.footer-legal {
  color: var(--text-3);
  font-size: 13px;
}

/* ===== Redirect page (/app) ===== */

.redirect-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
}

.redirect-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  padding-top: 40px;
  padding-bottom: 40px;
}

.redirect-title {
  margin-top: 24px;
  font-size: clamp(1.6rem, 4vw, 2.1rem);
  font-weight: 700;
  letter-spacing: -0.01em;
}

.redirect-text {
  margin: 12px 0 26px;
  max-width: 40ch;
  color: var(--text-2);
}

.redirect-back {
  margin-top: 20px;
  font-size: 14px;
}

.redirect-back a {
  color: var(--text-2);
}

.redirect-back a:hover {
  color: var(--text);
  text-decoration: underline;
  text-underline-offset: 2px;
}

/* ===== Responsive ===== */

@media (max-width: 760px) {
  .header-nav {
    display: none; /* anchors live in the footer on phones; keep the header light */
  }

  .features {
    grid-template-columns: 1fr;
    gap: 14px;
  }

  .how-list {
    grid-template-columns: 1fr;
    gap: 24px;
  }

  .hero-thread {
    opacity: 0.08;
  }
}

@media (max-width: 480px) {
  .container {
    padding: 0 18px;
  }

  .brand-word {
    font-size: 16px;
  }

  .header-actions .btn-ghost {
    display: none; /* keep the header light on phones; CTA lives in the hero */
  }
}

/* ===== Motion & depth ===== */

/* Scroll-reveal: elements rise + fade in when they enter the viewport. The
   per-element delay (--rd) staggers a group. JS adds .in via IntersectionObserver. */
.reveal {
  opacity: 0;
  transform: translateY(16px);
  transition: opacity 600ms ease, transform 600ms cubic-bezier(0.16, 1, 0.3, 1);
  transition-delay: var(--rd, 0ms);
}

.reveal.in {
  opacity: 1;
  transform: none;
}

/* Feature cards stagger left-to-right. */
.features .feature:nth-child(2) {
  --rd: 90ms;
}
.features .feature:nth-child(3) {
  --rd: 180ms;
}

/* Hero logo: fades up on load, then breathes gently. */
.hero-mark {
  animation: markIn 700ms cubic-bezier(0.16, 1, 0.3, 1) both,
    floatY 6s ease-in-out 900ms infinite;
}

@keyframes markIn {
  from {
    opacity: 0;
    transform: translateY(14px) scale(0.96);
  }
  to {
    opacity: 1;
    transform: none;
  }
}

@keyframes floatY {
  0%,
  100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-7px);
  }
}

/* Hero thread: draws itself in, then drifts slowly side to side (depth). */
.hero-thread {
  animation: threadDrift 20s ease-in-out infinite alternate;
}

.thread-line {
  stroke-dasharray: 1;
  stroke-dashoffset: 1;
  animation: threadDraw 2.4s ease 200ms forwards;
}

.thread-2 {
  opacity: 0.55;
  animation-delay: 500ms;
}

@keyframes threadDraw {
  to {
    stroke-dashoffset: 0;
  }
}

@keyframes threadDrift {
  from {
    transform: translateX(-14px);
  }
  to {
    transform: translateX(14px);
  }
}

/* Hover lift (pointer devices only). */
@media (hover: hover) {
  .feature {
    transition: transform 180ms ease, box-shadow 180ms ease, border-color 180ms ease;
  }

  .feature:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-card);
    border-color: rgba(168, 84, 50, 0.32);
  }

  .feature-icon {
    transition: transform 180ms ease;
  }

  .feature:hover .feature-icon {
    transform: scale(1.06);
  }
}

@media (prefers-reduced-motion: reduce) {
  html {
    scroll-behavior: auto;
  }

  .btn,
  .lang-btn {
    transition: none;
  }

  /* No entrance/idle motion: show everything in its final state. */
  .reveal {
    opacity: 1;
    transform: none;
    transition: none;
  }

  .hero-mark,
  .hero-thread,
  .thread-line {
    animation: none;
  }

  .thread-line {
    stroke-dashoffset: 0;
  }
}