/* =========================================================
   CyTutor 小辅星球 · base
   Reset, tokens, typography, shared primitives
   ========================================================= */

:root {
  --paper: #FFF9F2;
  --paper-2: #F8EEE2;
  --paper-deep: #F0E2D2;
  --surface: #FFFFFF;
  --ink: #1F2A37;
  --ink-soft: #4E5A68;
  --muted: #7C8798;
  --line: rgba(31, 42, 55, 0.10);
  --line-strong: rgba(31, 42, 55, 0.16);

  --coral: #FF6B4A;
  --coral-deep: #E85333;
  --coral-soft: #FFE3DA;
  --teal: #1FAE9A;
  --teal-deep: #138A7A;
  --teal-soft: #DDF5F0;
  --yellow: #FFD166;
  --yellow-soft: #FFF1C9;

  --shadow-sm: 0 8px 20px rgba(31, 42, 55, 0.06);
  --shadow-md: 0 18px 50px rgba(31, 42, 55, 0.10);
  --shadow-lg: 0 30px 80px rgba(31, 42, 55, 0.14);

  --radius: 28px;
  --radius-sm: 16px;
  --radius-pill: 999px;
  --container: 1160px;

  --font: "PingFang SC", "HarmonyOS Sans SC", "Noto Sans SC", "Microsoft YaHei",
    system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  --ease: cubic-bezier(0.2, 0.7, 0.2, 1);
}

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

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  background-color: var(--paper);
  background-image:
    radial-gradient(rgba(31, 42, 55, 0.035) 1px, transparent 1px),
    radial-gradient(900px 520px at 92% -6%, rgba(255, 107, 74, 0.13), transparent 62%),
    radial-gradient(760px 520px at -10% 18%, rgba(31, 174, 154, 0.10), transparent 60%),
    radial-gradient(720px 500px at 50% 108%, rgba(255, 209, 102, 0.12), transparent 60%);
  background-size: 24px 24px, auto, auto, auto;
  background-attachment: fixed;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  overflow-x: hidden;
}

body.modal-open,
body.nav-open {
  overflow: hidden;
}

img,
svg {
  display: block;
  max-width: 100%;
}

img {
  height: auto;
}

a {
  color: inherit;
}

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

button {
  cursor: pointer;
}

h1,
h2,
h3,
h4,
p,
figure,
blockquote {
  margin: 0;
}

h1,
h2,
h3,
h4 {
  font-weight: 800;
  letter-spacing: -0.04em;
  line-height: 1.12;
}

ul,
ol {
  margin: 0;
  padding: 0;
}

::selection {
  background: var(--yellow);
  color: var(--ink);
}

:focus-visible {
  outline: 3px solid var(--teal);
  outline-offset: 3px;
  border-radius: 6px;
}

.skip-link {
  position: fixed;
  top: 12px;
  left: 12px;
  z-index: 200;
  padding: 10px 16px;
  border-radius: 999px;
  background: var(--ink);
  color: #fff;
  font-size: 13px;
  text-decoration: none;
  transform: translateY(-160%);
  transition: transform 0.2s var(--ease);
}

.skip-link:focus {
  transform: translateY(0);
}

.svg-sprite {
  position: absolute;
  width: 0;
  height: 0;
  overflow: hidden;
}

.icon {
  width: 20px;
  height: 20px;
  flex: 0 0 auto;
  color: currentColor;
}

.sr-only {
  position: absolute !important;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

.container {
  width: min(calc(100% - 48px), var(--container));
  margin-inline: auto;
}

.section {
  position: relative;
  padding-block: clamp(64px, 9vw, 112px);
  scroll-margin-top: 92px;
}

.section-head {
  max-width: 740px;
  margin-bottom: clamp(32px, 5vw, 56px);
}

.section-head.center {
  margin-inline: auto;
  text-align: center;
}

.section-head.center .eyebrow {
  justify-content: center;
}

.section-head h2 {
  margin: 14px 0 16px;
  font-size: clamp(32px, 4.4vw, 54px);
}

.section-head p {
  max-width: 640px;
  color: var(--ink-soft);
  font-size: clamp(15px, 1.6vw, 17px);
  line-height: 1.8;
}

.section-head.center p {
  margin-inline: auto;
}

.section-head-split {
  max-width: none;
  display: grid;
  grid-template-columns: minmax(0, 1.1fr) minmax(0, 0.9fr);
  gap: 40px;
  align-items: end;
}

.capabilities .section-head-split {
  grid-template-columns: minmax(0, 1.28fr) minmax(0, 0.72fr);
}

.capabilities .section-head h2 {
  font-size: clamp(30px, 3.6vw, 46px);
}

.section-head-split p {
  margin-bottom: 6px;
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--coral-deep);
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.10em;
  text-transform: uppercase;
}

.eyebrow.light {
  color: var(--yellow);
}

.eyebrow-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--coral);
  box-shadow: 0 0 0 4px var(--coral-soft);
}

.mobile-only {
  display: none;
}

.nowrap {
  white-space: nowrap;
}

.marker {
  position: relative;
  display: inline-block;
  z-index: 0;
  color: var(--ink);
}

.marker::after {
  content: "";
  position: absolute;
  left: -1.5%;
  right: -1.5%;
  bottom: 0.05em;
  height: 0.34em;
  z-index: -1;
  border-radius: 4px;
  background: var(--yellow);
  transform: rotate(-1.2deg);
}

.footnote {
  margin-top: 14px;
  color: var(--muted);
  font-size: 12px;
  line-height: 1.7;
}

.footnote.center {
  text-align: center;
}

@media (max-width: 900px) {
  .mobile-only {
    display: inline;
  }

  .section-head-split,
  .capabilities .section-head-split {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .section-head-split p {
    margin-bottom: 0;
  }
}

@media (max-width: 560px) {
  .container {
    width: min(calc(100% - 36px), var(--container));
  }

  .section {
    padding-block: 60px;
  }

  .section-head {
    margin-bottom: 28px;
  }
}