/* Homepage — browse, hero, book picker */
/* —— Top bar —— */
    

    

    

    

    

    

    

    /* —— Compact bright hero —— */
    .hero {
      position: relative;
      min-height: 0;
      display: grid;
      align-items: center;
      overflow: hidden;
      color: var(--ink);
      background:
        radial-gradient(ellipse 65% 90% at 95% 0%, #ffef5a 0%, transparent 52%),
        radial-gradient(ellipse 50% 80% at -5% 110%, #5fe0c8 0%, transparent 48%),
        radial-gradient(ellipse 55% 70% at 40% -10%, #7ecbff 0%, transparent 50%),
        linear-gradient(160deg, #d9f2ff 0%, #fff6d6 45%, #d8faf0 100%);
    }

    .hero-visual {
      position: absolute;
      inset: 0;
      pointer-events: none;
    }

    .hero-visual .grid {
      position: absolute;
      inset: 0;
      background-image:
        linear-gradient(rgba(18, 24, 32, 0.045) 1px, transparent 1px),
        linear-gradient(90deg, rgba(18, 24, 32, 0.045) 1px, transparent 1px);
      background-size: 36px 36px;
      mask-image: radial-gradient(ellipse 60% 70% at 75% 35%, #000 10%, transparent 70%);
      opacity: 0.7;
    }

    .orb {
      position: absolute;
      border-radius: 50%;
      border: 2px solid rgba(18, 24, 32, 0.1);
      animation: drift 12s ease-in-out infinite;
    }

    .orb-a {
      width: min(16vw, 88px);
      height: min(16vw, 88px);
      left: 8%;
      top: 32%;
      animation-delay: 0s;
      background: rgba(126, 203, 255, 0.45);
    }

    .orb-b {
      width: min(12vw, 72px);
      height: min(12vw, 72px);
      right: 26%;
      top: 48%;
      animation-delay: -4s;
      border-color: rgba(200, 150, 20, 0.35);
      background: rgba(255, 239, 90, 0.55);
    }

    .orb-c {
      width: 40px;
      height: 40px;
      right: 18%;
      bottom: 22%;
      animation-delay: -7s;
      background: rgba(255, 120, 70, 0.55);
      border: none;
    }

    .sq {
      position: absolute;
      width: 28px;
      height: 28px;
      border: 2px solid rgba(18, 24, 32, 0.16);
      transform: rotate(18deg);
      right: 38%;
      top: 28%;
      animation: spin-slow 28s linear infinite;
    }

    .hero-inner {
      position: relative;
      z-index: 1;
      width: min(1120px, calc(100% - 48px));
      margin: 0 auto;
      padding: 80px 0 40px;
      display: grid;
      gap: 28px;
      animation: rise 0.7s ease both;
    }

    

    .hero-books {
      display: grid;
      grid-template-columns: repeat(2, minmax(0, 1fr));
      gap: 16px;
      align-items: stretch;
    }

    .book-pick {
      display: grid;
      grid-template-columns: auto 1fr;
      gap: 16px;
      align-items: center;
      padding: 14px 16px 14px 14px;
      background: rgba(255, 255, 255, 0.72);
      border: 1px solid rgba(18, 24, 32, 0.08);
      border-radius: 18px;
      backdrop-filter: blur(10px);
      box-shadow: 0 12px 32px rgba(18, 24, 32, 0.06);
      transition: transform 0.25s ease, box-shadow 0.25s ease, border-color 0.25s ease;
    }

    .book-pick:hover {
      transform: translateY(-2px);
      box-shadow: 0 18px 40px rgba(18, 24, 32, 0.1);
      border-color: rgba(18, 24, 32, 0.12);
    }

    .book-pick.is-active {
      border-color: transparent;
      box-shadow:
        0 0 0 2px var(--pick-accent, var(--teal-deep)),
        0 18px 40px rgba(18, 24, 32, 0.1);
    }

    .book-pick-shanghai {
      --pick-accent: var(--teal-deep);
    }

    .book-pick-sg {
      --pick-accent: var(--sg-deep);
    }

    .book-pick .hero-cover {
      margin: 0;
      width: 92px;
      flex: none;
    }

    .hero-cover-frame {
      position: relative;
      padding: 0;
      background: transparent;
      box-shadow: none;
      transform: none;
      transition: transform 0.35s ease, filter 0.35s ease;
    }

    .book-pick:hover .hero-cover-frame {
      transform: translateY(-3px);
      filter: drop-shadow(0 14px 22px rgba(18, 24, 32, 0.14));
    }

    .hero-cover-media {
      display: block;
      width: 100%;
      height: auto;
      border-radius: 4px;
    }

    .book-pick-sg .hero-cover-media {
      border-radius: 3px;
    }

    .hero-cover-spine {
      display: none;
    }

    .book-pick-body {
      display: grid;
      gap: 4px;
      min-width: 0;
    }

    .book-pick-kicker {
      margin: 0;
      font-size: 0.72rem;
      font-weight: 700;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      color: var(--pick-accent, var(--teal-deep));
    }

    .book-pick-title {
      margin: 0;
      font-family: Fraunces, Georgia, serif;
      font-size: clamp(1.05rem, 2vw, 1.28rem);
      font-weight: 700;
      color: var(--ink);
      line-height: 1.2;
    }

    .book-pick-desc {
      margin: 0;
      font-size: 0.9rem;
      color: var(--ink-soft);
      line-height: 1.35;
    }

    .cta-row {
      display: flex;
      flex-wrap: wrap;
      gap: 8px;
    }

    .book-pick .cta {
      margin-top: 2px;
    }

    .cta {
      appearance: none;
      display: inline-flex;
      align-items: center;
      justify-content: center;
      padding: 8px 14px;
      border-radius: 999px;
      border: 1.5px solid transparent;
      font-family: inherit;
      font-size: 0.84rem;
      font-weight: 700;
      line-height: 1.2;
      cursor: pointer;
      background: transparent;
      transition: transform 0.2s ease, background 0.2s ease, box-shadow 0.2s ease, border-color 0.2s ease, opacity 0.2s ease;
    }

    .cta:hover { transform: translateY(-2px); }

    .cta:active {
      transform: translateY(1px) scale(0.96);
    }

    .cta:focus-visible {
      outline: 3px solid rgba(18, 24, 32, 0.35);
      outline-offset: 3px;
    }

    /* First Semester — selected = solid teal */
    .cta-primary.is-selected {
      background: var(--teal-deep);
      color: #fff;
      border-color: var(--teal-deep);
      box-shadow:
        0 0 0 4px rgba(10, 107, 107, 0.55),
        0 14px 30px rgba(7, 79, 79, 0.38);
      transform: translateY(-2px);
    }

    .cta-primary:not(.is-selected) {
      background: #fff;
      color: var(--teal-deep);
      border-color: rgba(7, 79, 79, 0.35);
      box-shadow: 0 2px 8px rgba(18, 24, 32, 0.05);
      opacity: 0.78;
    }

    .cta-primary:not(.is-selected):hover {
      opacity: 1;
      border-color: var(--teal-deep);
      background: #f0faf9;
    }

    .cta-primary.is-selected:active {
      background: #053838;
      box-shadow:
        0 0 0 3px rgba(10, 107, 107, 0.45),
        0 6px 16px rgba(7, 79, 79, 0.3);
    }

    /* Second Semester — selected = solid copper */
    .cta-secondary.is-selected {
      background: linear-gradient(180deg, #d17a3a, var(--s2-deep));
      color: #fff;
      border-color: var(--s2-deep);
      box-shadow:
        0 0 0 4px rgba(194, 106, 45, 0.55),
        0 14px 30px rgba(138, 63, 18, 0.35);
      transform: translateY(-2px);
    }

    .cta-secondary:not(.is-selected) {
      background: #fff;
      color: var(--s2-deep);
      border-color: rgba(194, 106, 45, 0.35);
      box-shadow: 0 2px 8px rgba(18, 24, 32, 0.05);
      opacity: 0.78;
    }

    .cta-secondary:not(.is-selected):hover {
      opacity: 1;
      border-color: var(--s2);
      background: #fff8f2;
    }

    .cta-secondary.is-selected:active {
      background: linear-gradient(180deg, #b85f28, #6d3010);
      box-shadow:
        0 0 0 3px rgba(194, 106, 45, 0.45),
        0 6px 16px rgba(138, 63, 18, 0.28);
    }

    .cta-secondary:not(.is-selected):active {
      background: #ffe8d4;
      border-color: var(--s2-deep);
    }

    /* Singapore Intensive — selected = solid navy */
    .cta-sg.is-selected {
      background: linear-gradient(180deg, #2a62a8, var(--sg-deep));
      color: #fff;
      border-color: var(--sg-deep);
      box-shadow:
        0 0 0 4px rgba(30, 77, 140, 0.5),
        0 14px 30px rgba(22, 58, 107, 0.35);
      transform: translateY(-2px);
    }

    .cta-sg:not(.is-selected) {
      background: #fff;
      color: var(--sg-deep);
      border-color: rgba(30, 77, 140, 0.35);
      box-shadow: 0 2px 8px rgba(18, 24, 32, 0.05);
      opacity: 0.78;
    }

    .cta-sg:not(.is-selected):hover {
      opacity: 1;
      border-color: var(--sg);
      background: #f0f5fb;
    }

    .cta-sg.is-selected:active {
      background: linear-gradient(180deg, #1a4578, #0f2a4f);
      box-shadow:
        0 0 0 3px rgba(30, 77, 140, 0.45),
        0 6px 16px rgba(22, 58, 107, 0.28);
    }

    /* —— Browse section —— */
    .browse {
      width: min(1120px, calc(100% - 48px));
      margin: 0 auto;
      padding: 36px 0 80px;
    }

    .semester {
      display: none;
      gap: 14px;
      animation: rise 0.45s ease both;
    }

    .semester.is-active {
      display: grid;
      grid-template-columns: 1fr 1fr;
      align-items: stretch;
    }

    .semester-head {
      grid-column: 1 / -1;
      border-radius: var(--radius);
      padding: 26px 28px 24px;
      color: #f8fbfd;
      box-shadow: var(--shadow);
      background:
        radial-gradient(ellipse 70% 120% at 100% 0%, rgba(255,255,255,0.12) 0%, transparent 55%),
        linear-gradient(135deg, var(--teal-deep), #16384a);
    }

    .semester.second-semester .semester-head {
      background:
        radial-gradient(ellipse 70% 120% at 100% 0%, rgba(255,255,255,0.12) 0%, transparent 55%),
        linear-gradient(135deg, var(--s2), var(--s2-deep));
    }

    .semester.singapore-book .semester-head {
      background:
        radial-gradient(ellipse 70% 120% at 100% 0%, rgba(255,255,255,0.12) 0%, transparent 55%),
        linear-gradient(135deg, var(--sg), var(--sg-deep));
    }

    .semester-head .semester-eyebrow {
      display: inline-block;
      font-size: 0.75rem;
      letter-spacing: 0.08em;
      text-transform: uppercase;
      opacity: 0.82;
      margin: 0 0 6px;
    }

    .semester-head .semester-title {
      font-size: clamp(1.4rem, 3.5vw, 1.85rem);
      color: #fff;
      margin: 0 0 6px;
    }

    .semester-head .semester-lead {
      margin: 0;
      max-width: 40rem;
      opacity: 0.92;
      font-size: 1.02rem;
    }

    details.chapter {
      background: var(--panel);
      border: 1px solid var(--line);
      border-radius: 14px;
      box-shadow: 0 8px 24px rgba(18, 24, 32, 0.04);
      overflow: hidden;
      height: 100%;
      display: flex;
      flex-direction: column;
      transition: box-shadow 0.2s ease, transform 0.2s ease;
    }

    details.chapter:hover {
      transform: translateY(-1px);
      box-shadow: 0 12px 28px rgba(18, 24, 32, 0.07);
    }

    details.chapter[open] {
      grid-column: 1 / -1;
      box-shadow: var(--shadow);
      transform: none;
      height: auto;
    }

    .chapter-summary {
      list-style: none;
      display: grid;
      grid-template-columns: 1fr auto;
      gap: 16px;
      align-items: center;
      padding: 18px 20px;
      cursor: pointer;
      user-select: none;
      flex: 1;
      min-height: 108px;
      border-left: 4px solid var(--teal);
      box-sizing: border-box;
    }

    .second-semester .chapter-summary {
      border-left-color: var(--s2);
    }

    .singapore-book .chapter-summary {
      border-left-color: var(--sg);
    }

    .chapter-summary::-webkit-details-marker { display: none; }

    .chapter-summary:hover {
      background: linear-gradient(90deg, var(--sand), transparent 55%);
    }

    .chapter-title {
      display: block;
      font-family: Fraunces, Georgia, serif;
      font-size: 1.14rem;
      font-weight: 700;
      color: var(--teal-deep);
      margin-bottom: 4px;
    }

    .second-semester .chapter-title { color: var(--s2-deep); }

    .singapore-book .chapter-title { color: var(--sg-deep); }

    .chapter-lead {
      display: block;
      font-size: 0.9rem;
      color: var(--ink-soft);
      line-height: 1.4;
    }

    .chapter-meta {
      display: flex;
      flex-direction: column;
      align-items: flex-end;
      justify-content: center;
      gap: 8px;
    }

    .chapter-meta .count {
      font-size: 0.8rem;
      font-weight: 700;
      color: var(--ink-soft);
      background: var(--sand);
      padding: 4px 9px;
      border-radius: 999px;
    }

    .chev {
      width: 10px;
      height: 10px;
      border-right: 2px solid var(--ink-soft);
      border-bottom: 2px solid var(--ink-soft);
      transform: rotate(45deg);
      transition: transform 0.25s ease;
      margin-bottom: 4px;
    }

    details.chapter[open] .chev {
      transform: rotate(-135deg);
      margin-bottom: 0;
      margin-top: 4px;
    }

    .lessons {
      display: grid;
      gap: 8px;
      padding: 0 14px 16px;
      border-top: 1px solid var(--line);
      padding-top: 12px;
    }

    .lesson {
      display: grid;
      grid-template-columns: 58px 1fr auto;
      gap: 12px;
      align-items: center;
      text-decoration: none;
      color: inherit;
      padding: 12px 14px;
      border-radius: 12px;
      border: 1px solid transparent;
      background: linear-gradient(90deg, var(--sand), #fff 38%);
      transition: transform 0.2s ease, border-color 0.2s ease, box-shadow 0.2s ease;
    }

    .lesson:hover {
      transform: translateX(3px);
      border-color: #c5ced8;
      box-shadow: 0 8px 20px rgba(18, 24, 32, 0.06);
    }

    .lesson .num {
      font-family: Fraunces, Georgia, serif;
      font-size: 1.25rem;
      font-weight: 700;
      color: var(--teal);
      line-height: 1;
    }

    .second-semester .lesson .num { color: var(--s2-soft); }

    .singapore-book .lesson .num { color: var(--sg-soft); }

    .lesson h3 {
      margin: 0 0 2px;
      font-size: 1rem;
      color: var(--ink);
    }

    .lesson p {
      margin: 0;
      font-size: 0.86rem;
      color: var(--ink-soft);
    }

    .lesson .go {
      font-size: 0.84rem;
      font-weight: 700;
      color: var(--teal-deep);
      white-space: nowrap;
    }

    @media (max-width: 820px) {
      .hero-books { grid-template-columns: 1fr; }
    }

    @media (max-width: 640px) {
      
      .hero-inner {
        width: calc(100% - 32px);
        padding: 68px 0 28px;
      }
      .book-pick {
        grid-template-columns: 78px 1fr;
        gap: 12px;
        padding: 12px;
      }
      .book-pick .hero-cover { width: 78px; }
      .book-pick:hover .hero-cover-frame { transform: none; filter: none; }
      .hero { min-height: 0; align-items: center; }
      .cta { padding: 7px 12px; font-size: 0.8rem; }
      .browse { width: calc(100% - 32px); }
      .semester.is-active { grid-template-columns: 1fr; }
      .chapter-summary {
        grid-template-columns: 1fr;
        gap: 10px;
        min-height: 0;
      }
      .chapter-meta {
        flex-direction: row;
        align-items: center;
        justify-content: flex-start;
      }
      .lesson {
        grid-template-columns: 48px 1fr;
        grid-template-rows: auto auto;
      }
      .lesson .go { grid-column: 2; }
    }