/* 第七区 AIGC 创作实战课 — static site
   Paper #f3f3ef · Ink #282a29 · Point red #b44c51
   System Chinese font stack only (no Google Fonts)
*/

:root {
  --paper: #f3f3ef;
  --paper-2: #ebebe6;
  --ink: #282a29;
  --ink-soft: rgba(40, 42, 41, 0.72);
  --ink-mute: rgba(40, 42, 41, 0.48);
  --ink-line: rgba(40, 42, 41, 0.16);
  --ink-line-strong: rgba(40, 42, 41, 0.28);
  --red: #b44c51;
  --red-soft: rgba(180, 76, 81, 0.12);
  --header-h: 64px;
  --container: 1120px;
  --gutter: 24px;
  --font: "PingFang SC", "Hiragino Sans GB", "Noto Sans SC", "Microsoft YaHei", system-ui, -apple-system, sans-serif;
  --ease: cubic-bezier(0.22, 1, 0.36, 1);
}

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

html {
  scroll-behavior: smooth;
  scroll-padding-top: calc(var(--header-h) + 16px);
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.65;
  color: var(--ink);
  background: var(--paper);
  -webkit-font-smoothing: antialiased;
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration-thickness: 1px;
  text-underline-offset: 0.2em;
}

a:hover {
  color: var(--red);
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: 0;
  cursor: pointer;
}

ul, ol {
  margin: 0;
  padding: 0;
  list-style: none;
}

h1, h2, h3, h4, h5, p {
  margin: 0;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--ink);
  color: var(--paper);
  padding: 8px 16px;
  z-index: 1000;
}

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

.container {
  width: min(100% - (var(--gutter) * 2), var(--container));
  margin-inline: auto;
}

/* ——— Header ——— */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  height: var(--header-h);
  background: rgba(243, 243, 239, 0.92);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--ink-line);
}

.header-inner {
  width: min(100% - (var(--gutter) * 2), var(--container));
  margin-inline: auto;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 12px;
  text-decoration: none;
  min-width: 0;
}

.brand:hover {
  color: var(--ink);
}

.brand-logo {
  width: 96px;
  height: auto;
  flex-shrink: 0;
}

.brand-divider {
  width: 1px;
  height: 18px;
  background: var(--ink-line-strong);
  flex-shrink: 0;
}

.brand-course {
  font-size: 13px;
  letter-spacing: 0.04em;
  color: var(--ink-soft);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.nav-toggle {
  display: none;
  width: 44px;
  height: 44px;
  align-items: center;
  justify-content: center;
  flex-direction: column;
  gap: 6px;
  margin-right: -10px;
}

.nav-toggle-bar {
  display: block;
  width: 20px;
  height: 1.5px;
  background: var(--ink);
  transition: transform 0.25s var(--ease), opacity 0.2s;
}

.nav-open .nav-toggle-bar:first-child {
  transform: translateY(3.75px) rotate(45deg);
}

.nav-open .nav-toggle-bar:last-child {
  transform: translateY(-3.75px) rotate(-45deg);
}

.site-nav {
  display: flex;
  align-items: center;
  gap: 4px 20px;
}

.site-nav a {
  font-size: 13px;
  letter-spacing: 0.06em;
  text-decoration: none;
  color: var(--ink-soft);
  padding: 8px 0;
}

.site-nav a:hover,
.site-nav a.is-active {
  color: var(--ink);
}

.site-nav .nav-cta {
  padding: 8px 14px;
  border: 1px solid var(--ink);
  color: var(--ink);
  letter-spacing: 0.08em;
}

.site-nav .nav-cta:hover {
  background: var(--ink);
  color: var(--paper);
}

/* ——— Shared section bits ——— */
.section-label {
  font-size: 11px;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-mute);
  margin-bottom: 12px;
}

.section-title {
  font-size: clamp(28px, 4vw, 40px);
  font-weight: 600;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.section-lead {
  margin-top: 12px;
  max-width: 54ch;
  color: var(--ink-soft);
  font-size: 15px;
}

.section-head {
  margin-bottom: 40px;
}

/* ——— Hero ——— */
.hero {
  padding: 56px 0 64px;
  border-bottom: 1px solid var(--ink-line);
}

.hero-grid {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 24px 48px;
  align-items: end;
}

.hero-meta {
  grid-column: 1 / -1;
  display: flex;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
  padding-bottom: 20px;
  border-bottom: 1px solid var(--ink-line);
}

.eyebrow {
  font-size: 11px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--ink-mute);
  margin: 0;
}

.hero-main {
  max-width: 720px;
}

.hero-title {
  font-size: clamp(40px, 7.5vw, 72px);
  font-weight: 700;
  line-height: 1.08;
  letter-spacing: -0.03em;
}

.hero-sub {
  margin-top: 20px;
  font-size: clamp(16px, 2vw, 20px);
  color: var(--ink-soft);
}

.hero-tagline {
  margin-top: 16px;
  font-size: 15px;
  letter-spacing: 0.04em;
  color: var(--red);
}

.hero-badge {
  text-align: right;
  align-self: start;
  padding-top: 8px;
}

.badge-num {
  display: block;
  font-size: clamp(72px, 12vw, 120px);
  font-weight: 700;
  line-height: 0.9;
  letter-spacing: -0.04em;
  color: var(--ink);
}

.badge-label,
.badge-dates {
  display: block;
  margin-top: 8px;
  font-size: 12px;
  letter-spacing: 0.08em;
  color: var(--ink-soft);
}

.hero-facts {
  grid-column: 1 / -1;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0;
  margin-top: 16px;
  border-top: 1px solid var(--ink-line);
}

.hero-facts li {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 12px;
  padding: 18px 20px 18px 0;
  border-bottom: 1px solid var(--ink-line);
}

.hero-facts li:nth-child(odd) {
  padding-right: 24px;
  border-right: 1px solid var(--ink-line);
}

.hero-facts li:nth-child(even) {
  padding-left: 24px;
}

.fact-k {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ink-mute);
  padding-top: 2px;
}

.fact-v {
  font-size: 14px;
  line-height: 1.5;
}

/* ——— Outcomes ——— */
.outcomes {
  padding: 72px 0;
  background: var(--paper-2);
  border-bottom: 1px solid var(--ink-line);
}

.outcome-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1px;
  background: var(--ink-line);
  border: 1px solid var(--ink-line);
  margin-top: 36px;
}

.outcome-card {
  background: var(--paper);
  padding: 28px 24px 32px;
}

.outcome-idx {
  display: block;
  font-size: 12px;
  letter-spacing: 0.14em;
  color: var(--red);
  margin-bottom: 20px;
}

.outcome-card h3 {
  font-size: 24px;
  font-weight: 600;
  margin-bottom: 12px;
}

.outcome-card p {
  font-size: 14px;
  color: var(--ink-soft);
  max-width: 32ch;
}

.outcome-foot {
  margin-top: 28px;
  font-size: 13px;
  letter-spacing: 0.12em;
  color: var(--ink-mute);
}

/* ——— Schedule ——— */
.schedule {
  padding: 72px 0;
  border-bottom: 1px solid var(--ink-line);
}

.schedule-rail {
  display: grid;
  grid-template-columns: repeat(6, 1fr);
  gap: 1px;
  background: var(--ink-line);
  border: 1px solid var(--ink-line);
}

.schedule-rail a {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 20px 16px;
  background: var(--paper);
  text-decoration: none;
  min-height: 140px;
  transition: background 0.2s var(--ease);
}

.schedule-rail a:hover {
  background: var(--paper-2);
  color: var(--ink);
}

.rail-num {
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--red);
}

.rail-date {
  font-size: 22px;
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1;
}

.rail-dow {
  font-size: 12px;
  color: var(--ink-mute);
}

.rail-title {
  margin-top: auto;
  font-size: 14px;
  font-weight: 500;
}

/* ——— Lessons ——— */
.lessons {
  padding: 72px 0 40px;
}

.lesson {
  padding: 48px 0;
  border-top: 1px solid var(--ink-line);
}

.lesson:first-of-type {
  border-top: 1px solid var(--ink-line-strong);
}

.lesson-head {
  display: grid;
  grid-template-columns: 120px 1fr;
  gap: 32px;
  margin-bottom: 36px;
  align-items: start;
}

.lesson-num-block {
  display: flex;
  flex-direction: column;
  gap: 4px;
  padding-top: 4px;
}

.lesson-word {
  font-size: 10px;
  letter-spacing: 0.2em;
  color: var(--ink-mute);
}

.lesson-num {
  font-size: 56px;
  font-weight: 700;
  line-height: 0.95;
  letter-spacing: -0.04em;
}

.lesson-date {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--red);
  margin-bottom: 10px;
}

.lesson-title {
  font-size: clamp(24px, 3.2vw, 32px);
  font-weight: 600;
  line-height: 1.25;
  letter-spacing: -0.02em;
}

.lesson-position {
  margin-top: 12px;
  font-size: 16px;
  color: var(--ink-soft);
  max-width: 48ch;
}
.lesson-source {
  margin-top: 12px;
  font-size: 12px;
  line-height: 1.55;
  color: var(--ink-mute);
  max-width: 62ch;
}


.lesson-body {
  padding-left: 152px;
}

.lesson-block {
  margin-bottom: 28px;
}

.lesson-block h4 {
  font-size: 12px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--ink-mute);
  margin-bottom: 14px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--ink-line);
}

.lesson-block ul {
  display: grid;
  gap: 10px;
}

.lesson-block ul li {
  position: relative;
  padding-left: 16px;
  font-size: 15px;
  color: var(--ink-soft);
}

.lesson-block ul li::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0.7em;
  width: 6px;
  height: 1px;
  background: var(--red);
}

.modules {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 16px 24px;
}

.module {
  padding: 16px 0;
  border-top: 1px solid var(--ink-line);
}

.module h5 {
  font-size: 15px;
  font-weight: 600;
  margin-bottom: 8px;
}

.module p {
  font-size: 14px;
  color: var(--ink-soft);
  line-height: 1.6;
}

.module strong {
  font-weight: 600;
  color: var(--ink);
}

.lesson-cols {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

.lesson-block.accent {
  margin-bottom: 0;
  padding: 20px 20px 22px;
  background: var(--paper-2);
  border: 1px solid var(--ink-line);
}

.lesson-block.accent h4 {
  border-bottom: 0;
  padding-bottom: 0;
  color: var(--red);
}

.lesson-block.accent p {
  font-size: 15px;
  color: var(--ink);
}

/* ——— Tools ——— */
.tools {
  padding: 72px 0;
  border-top: 1px solid var(--ink-line);
  border-bottom: 1px solid var(--ink-line);
  background: var(--paper-2);
}

.tool-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1px;
  background: var(--ink-line);
  border: 1px solid var(--ink-line);
}

.tool-card {
  background: var(--paper);
  padding: 24px 20px 28px;
}

.tool-card h3 {
  font-size: 13px;
  letter-spacing: 0.08em;
  color: var(--red);
  margin-bottom: 12px;
  font-weight: 500;
}

.tool-card p {
  font-size: 15px;
  line-height: 1.55;
}

/* ——— Instructor ——— */
.instructor {
  padding: 72px 0;
  border-bottom: 1px solid var(--ink-line);
}

.instructor-grid {
  display: grid;
  grid-template-columns: 1.4fr 0.8fr;
  gap: 48px;
  align-items: start;
}

.instructor-role {
  margin-top: 10px;
  font-size: 15px;
  color: var(--ink-soft);
}

.instructor-bio {
  margin-top: 28px;
  display: grid;
  gap: 14px;
  max-width: 58ch;
}

.instructor-bio p {
  font-size: 15px;
  color: var(--ink-soft);
}

.instructor-aside {
  padding: 28px 24px;
  border: 1px solid var(--ink-line);
  background: var(--paper-2);
}

.aside-label {
  font-size: 11px;
  letter-spacing: 0.16em;
  color: var(--ink-mute);
  margin-bottom: 16px;
}

.aside-name {
  font-size: 22px;
  font-weight: 600;
  margin-bottom: 6px;
}

.aside-co {
  font-size: 13px;
  color: var(--ink-soft);
  margin-bottom: 20px;
}

.aside-slogan {
  font-size: 15px;
  color: var(--red);
  margin-bottom: 20px;
}

.aside-link {
  font-size: 14px;
  letter-spacing: 0.04em;
}

/* ——— Contact ——— */
.contact {
  padding: 72px 0;
}

.contact-inner {
  max-width: 640px;
}

.contact-lead {
  margin-top: 14px;
  color: var(--ink-soft);
  font-size: 15px;
}

.contact-list {
  margin-top: 32px;
  border-top: 1px solid var(--ink-line);
}

.contact-list li {
  display: grid;
  grid-template-columns: 72px 1fr;
  gap: 16px;
  padding: 18px 0;
  border-bottom: 1px solid var(--ink-line);
  align-items: baseline;
}

.contact-k {
  font-size: 12px;
  letter-spacing: 0.1em;
  color: var(--ink-mute);
}

.contact-list a {
  font-size: 16px;
  text-decoration: none;
  border-bottom: 1px solid var(--ink-line-strong);
}

.contact-list a:hover {
  border-bottom-color: var(--red);
}

/* ——— Footer ——— */
.site-footer {
  border-top: 1px solid var(--ink-line);
  padding: 40px 0 48px;
  background: var(--ink);
  color: rgba(243, 243, 239, 0.88);
}

.site-footer a {
  color: rgba(243, 243, 239, 0.88);
}

.site-footer a:hover {
  color: #fff;
}

.footer-inner {
  display: flex;
  flex-wrap: wrap;
  gap: 28px 48px;
  align-items: flex-end;
  justify-content: space-between;
}

.footer-brand,
.footer-mid {
  flex: 1 1 220px;
}

.footer-end {
  flex: 0 0 auto;
}

.footer-logo {
  width: 88px;
  height: auto;
  margin-bottom: 14px;
  /* logo is charcoal+red on transparent; on dark footer invert charcoal via filter would break red.
     Use a light chip behind logo instead. */
  background: var(--paper);
  padding: 8px 10px;
}

.footer-brand p {
  font-size: 14px;
}

.footer-co {
  margin-top: 4px;
  font-size: 12px;
  color: rgba(243, 243, 239, 0.5);
}

.footer-slogan {
  font-size: 16px;
  color: #fff;
  margin-bottom: 8px;
}

.footer-course {
  font-size: 12px;
  letter-spacing: 0.08em;
  color: rgba(243, 243, 239, 0.5);
}

.footer-end {
  display: flex;
  flex-direction: column;
  gap: 12px;
  align-items: flex-end;
  font-size: 13px;
}

.back-top {
  text-decoration: none;
  border-bottom: 1px solid rgba(243, 243, 239, 0.35);
  padding-bottom: 2px;
}

/* ——— Responsive ——— */
@media (max-width: 960px) {
  .hero-grid {
    grid-template-columns: 1fr;
  }

  .hero-badge {
    text-align: left;
    display: flex;
    align-items: baseline;
    gap: 16px;
    flex-wrap: wrap;
  }

  .badge-num {
    font-size: 64px;
  }

  .hero-facts {
    grid-template-columns: 1fr;
  }

  .hero-facts li,
  .hero-facts li:nth-child(odd),
  .hero-facts li:nth-child(even) {
    border-right: 0;
    padding-left: 0;
    padding-right: 0;
  }

  .outcome-grid,
  .tool-grid {
    grid-template-columns: 1fr;
  }

  .schedule-rail {
    grid-template-columns: repeat(3, 1fr);
  }

  .lesson-head {
    grid-template-columns: 80px 1fr;
    gap: 20px;
  }

  .lesson-body {
    padding-left: 0;
  }

  .lesson-num {
    font-size: 44px;
  }

  .modules,
  .lesson-cols,
  .instructor-grid {
    grid-template-columns: 1fr;
  }

  .footer-end {
    align-items: flex-start;
  }
}

@media (max-width: 720px) {
  :root {
    --header-h: 56px;
    --gutter: 18px;
  }

  .nav-toggle {
    display: flex;
  }

  .brand-course {
    display: none;
  }

  .brand-divider {
    display: none;
  }

  .site-nav {
    position: fixed;
    inset: var(--header-h) 0 auto 0;
    display: none;
    flex-direction: column;
    align-items: stretch;
    gap: 0;
    padding: 8px 18px 20px;
    background: var(--paper);
    border-bottom: 1px solid var(--ink-line);
    box-shadow: 0 16px 32px rgba(40, 42, 41, 0.08);
  }

  .nav-open .site-nav {
    display: flex;
  }

  .site-nav a {
    padding: 14px 0;
    border-bottom: 1px solid var(--ink-line);
    font-size: 15px;
    letter-spacing: 0.04em;
  }

  .site-nav .nav-cta {
    margin-top: 12px;
    text-align: center;
    border-bottom: 1px solid var(--ink);
  }

  .hero {
    padding: 36px 0 48px;
  }

  .hero-title {
    font-size: clamp(34px, 11vw, 48px);
  }

  .eyebrow-right {
    display: none;
  }

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

  .schedule-rail a {
    min-height: 120px;
  }

  .lesson-head {
    grid-template-columns: 1fr;
    gap: 12px;
  }

  .lesson-num-block {
    flex-direction: row;
    align-items: baseline;
    gap: 10px;
  }

  .lesson-num {
    font-size: 36px;
  }

  .outcomes,
  .schedule,
  .lessons,
  .tools,
  .instructor,
  .contact {
    padding-top: 56px;
    padding-bottom: 56px;
  }

  .lessons {
    padding-bottom: 24px;
  }

  .lesson {
    padding: 36px 0;
  }
}

@media (max-width: 400px) {
  .schedule-rail {
    grid-template-columns: 1fr 1fr;
  }

  .hero-facts li {
    grid-template-columns: 56px 1fr;
  }

  .contact-list li {
    grid-template-columns: 1fr;
    gap: 6px;
  }
}

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

  *,
  *::before,
  *::after {
    transition: none !important;
  }
}