:root {
        --ink: #1f2430;
        --muted: #687082;
        --paper: #fbfafc;
        --surface: #ffffff;
        --purple: #4b2e83;
        --purple-2: #7c3aed;
        --lavender: #efe8fb;
        --green: #2e7d32;
        --green-2: #19a974;
        --mint: #e8f7ef;
        --pink: #d9468f;
        --rose: #fdebf4;
        --gold: #bd8b22;
        --cream: #fff8e6;
        --line: #e7e1ef;
        --shadow: 0 18px 48px rgba(38, 31, 70, 0.11);
        --radius: 18px;
      }

      * {
        box-sizing: border-box;
      }

      html {
        scroll-behavior: smooth;
      }

      body {
        margin: 0;
        font-family: Arial, Helvetica, sans-serif;
        background: var(--paper);
        color: var(--ink);
      }

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

      .page {
        width: min(1180px, calc(100% - 32px));
        margin: 0 auto;
      }

      .nav {
        position: sticky;
        top: 0;
        z-index: 10;
        border-bottom: 1px solid rgba(231, 225, 239, 0.9);
        background: rgba(251, 250, 252, 0.92);
        backdrop-filter: blur(14px);
      }

      .nav-inner {
        min-height: 78px;
        display: flex;
        align-items: center;
        justify-content: flex-start;
        gap: clamp(24px, 4vw, 56px);
      }

      .brand {
        display: inline-flex;
        align-items: center;
        gap: 12px;
        font-weight: 900;
        flex: 0 0 auto;
      }

      .brand > span {
        display: grid;
        line-height: 1.05;
        max-width: 180px;
      }

      .mark {
        display: grid;
        place-items: center;
        width: 84px;
        height: 52px;
        border-radius: 999px;
        background-color: #ffffff;
        background-image: url("assets/tic4edu-logo-cropped.png");
        background-position: center;
        background-repeat: no-repeat;
        background-size: contain;
        box-shadow: 0 8px 22px rgba(75, 46, 131, 0.13);
        font-size: 0;
      }

      .brand-logo {
        display: block;
        width: 84px;
        height: 52px;
        object-fit: contain;
        flex: 0 0 auto;
        border-radius: 999px;
        background: #ffffff;
        box-shadow: 0 8px 22px rgba(75, 46, 131, 0.13);
      }

      .brand-text {
        display: grid;
        line-height: 1.05;
      }

      .brand-title {
        display: block;
        font-size: 1.35rem;
        color: var(--ink);
      }

      .brand-subtitle {
        display: block;
        margin-top: 4px;
        color: var(--muted);
        font-size: 0.68rem;
        letter-spacing: 0.14em;
        text-transform: uppercase;
      }

      .nav-links {
        display: flex;
        align-items: center;
        justify-content: flex-start;
        flex-wrap: wrap;
        gap: 6px;
        color: var(--muted);
        font-size: 0.84rem;
        font-weight: 500;
        flex: 1 1 auto;
      }

      .nav-links a {
        padding: 8px 8px;
        border-radius: 999px;
        white-space: nowrap;
      }

      .nav-links a:hover {
        color: var(--purple);
        background: var(--lavender);
      }

      .nav-links a.active {
        font-weight: 650;
      }

      .hero {
        display: grid;
        grid-template-columns: minmax(0, 1.05fr) minmax(320px, 0.95fr);
        gap: clamp(28px, 5vw, 64px);
        align-items: center;
        padding: clamp(56px, 8vw, 98px) 0 72px;
      }

      .hero.center {
        display: block;
        text-align: center;
        max-width: 920px;
        margin: 0 auto;
      }

      .hero.center h1,
      .hero.center .hero-copy {
        margin-left: auto;
        margin-right: auto;
      }

      .kicker {
        margin: 0 0 14px;
        color: var(--purple-2);
        font-size: 0.78rem;
        font-weight: 900;
        letter-spacing: 0.16em;
        text-transform: uppercase;
      }

      h1,
      h2,
      h3,
      p {
        overflow-wrap: break-word;
      }

      h1 {
        margin: 0;
        max-width: 820px;
        color: var(--ink);
        font-size: clamp(3rem, 7vw, 5.8rem);
        line-height: 0.98;
        letter-spacing: 0;
      }

      .hero-copy {
        margin: 22px 0 0;
        max-width: 690px;
        color: var(--muted);
        font-size: clamp(1.05rem, 2vw, 1.24rem);
        line-height: 1.75;
      }

      .actions {
        display: flex;
        flex-wrap: wrap;
        gap: 12px;
        margin-top: 30px;
      }

      .button {
        display: inline-flex;
        align-items: center;
        justify-content: center;
        min-height: 48px;
        padding: 0 18px;
        border-radius: 12px;
        border: 1px solid transparent;
        font-weight: 900;
      }

      .button.primary {
        color: #ffffff;
        background: var(--purple-2);
        box-shadow: 0 14px 30px rgba(124, 58, 237, 0.24);
      }

      .button.secondary {
        color: var(--purple);
        background: #ffffff;
        border-color: var(--line);
      }

      .button.disabled {
        color: var(--muted);
        background: #f3f0f8;
        border-color: var(--line);
        cursor: not-allowed;
      }

      .hero-panel {
        border-radius: 28px;
        border: 1px solid var(--line);
        background:
          linear-gradient(135deg, rgba(239, 232, 251, 0.88), rgba(232, 247, 239, 0.9)),
          #ffffff;
        box-shadow: var(--shadow);
        padding: 26px;
      }

      .hero-product {
        display: block;
        width: min(100%, 320px);
        max-height: 320px;
        margin: 0 auto;
        object-fit: contain;
        border-radius: 28px;
      }

      .preview-window {
        overflow: hidden;
        border-radius: 22px;
        background: #ffffff;
        border: 1px solid rgba(75, 46, 131, 0.12);
      }

      .preview-top {
        padding: 18px;
        border-bottom: 1px solid var(--line);
        background: #ffffff;
      }

      .preview-top strong {
        display: block;
        font-size: 1.05rem;
      }

      .preview-top span {
        display: block;
        margin-top: 5px;
        color: var(--muted);
        font-size: 0.92rem;
      }

      .preview-list {
        display: grid;
        gap: 12px;
        padding: 18px;
      }

      .preview-card {
        display: grid;
        grid-template-columns: 52px 1fr;
        gap: 12px;
        align-items: center;
        min-height: 76px;
        padding: 12px;
        border-radius: 16px;
        font-weight: 900;
      }

      .preview-icon {
        display: grid;
        place-items: center;
        width: 52px;
        height: 52px;
        border-radius: 15px;
        background: rgba(255, 255, 255, 0.72);
      }

      .preview-card small {
        display: block;
        margin-top: 4px;
        color: var(--muted);
        font-weight: 700;
      }

      .bg-lavender { background: var(--lavender); color: var(--purple); }
      .bg-mint { background: var(--mint); color: #155f49; }
      .bg-rose { background: var(--rose); color: #9f245e; }
      .bg-cream { background: var(--cream); color: #7a5815; }

      section {
        padding: clamp(54px, 8vw, 88px) 0;
      }

      .section-heading {
        max-width: 780px;
        margin-bottom: 28px;
      }

      .section-heading.with-icon {
        display: grid;
        grid-template-columns: minmax(0, 1fr) minmax(220px, 360px);
        align-items: center;
        max-width: none;
        gap: clamp(28px, 7vw, 96px);
      }

      .section-heading.with-icon .section-copy {
        max-width: 780px;
      }

      .heading-icon {
        display: block;
        width: min(100%, 340px);
        margin-left: auto;
        border-radius: 28px;
        filter: drop-shadow(0 24px 44px rgba(45, 27, 105, 0.12));
      }

      h2 {
        margin: 0;
        color: var(--ink);
        font-size: clamp(2rem, 4vw, 3.2rem);
        line-height: 1.08;
        letter-spacing: 0;
      }

      .section-copy {
        margin: 16px 0 0;
        color: var(--muted);
        font-size: 1.06rem;
        line-height: 1.75;
      }

      .product-grid,
      .feature-grid {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 18px;
      }

      .grid-2,
      .grid-3 {
        display: grid;
        gap: 18px;
      }

      .grid-2 {
        grid-template-columns: repeat(2, minmax(0, 1fr));
      }

      .grid-3 {
        grid-template-columns: repeat(3, minmax(0, 1fr));
      }

      .feature-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
      }

      .product,
      .feature,
      .card,
      .bio,
      .notice {
        border: 1px solid var(--line);
        background: var(--surface);
        box-shadow: var(--shadow);
      }

      .card {
        min-height: 220px;
        border-radius: 20px;
        padding: 24px;
      }

      .card-number {
        display: inline-grid;
        place-items: center;
        width: 44px;
        height: 44px;
        border-radius: 14px;
        background: #f0e8ff;
        color: var(--purple);
        font-size: 0.95rem;
        font-weight: 900;
      }

      .app-preview {
        display: grid;
        grid-template-columns: 108px 1fr;
        gap: 20px;
        align-items: center;
        min-height: 0;
      }

      .app-preview img {
        display: block;
        width: 108px;
        height: 108px;
        object-fit: contain;
        border-radius: 24px;
        background: #ffffff;
        box-shadow: 0 14px 28px rgba(75, 46, 131, 0.12);
      }

      .card h3 {
        margin: 18px 0 10px;
        font-size: 1.5rem;
        line-height: 1.15;
      }

      .card p {
        margin: 0;
        color: var(--muted);
        line-height: 1.7;
      }

      .label {
        display: inline-flex;
        width: fit-content;
        padding: 8px 10px;
        border-radius: 999px;
        font-size: 0.74rem;
        font-weight: 900;
        letter-spacing: 0.12em;
        text-transform: uppercase;
      }

      .product {
        min-height: 330px;
        border-radius: 24px;
        padding: 26px;
        display: grid;
        align-content: space-between;
        gap: 26px;
      }

      .product-label {
        display: inline-flex;
        width: fit-content;
        padding: 8px 10px;
        border-radius: 999px;
        font-size: 0.74rem;
        font-weight: 900;
        letter-spacing: 0.12em;
        text-transform: uppercase;
      }

      .product h3,
      .feature h3 {
        margin: 18px 0 10px;
        font-size: 1.55rem;
        line-height: 1.15;
      }

      .product p,
      .feature p,
      .bio p,
      .notice p,
      .download-card p {
        margin: 0;
        color: var(--muted);
        line-height: 1.7;
      }

      .product-actions {
        display: flex;
        flex-wrap: wrap;
        gap: 10px;
      }

      .feature {
        min-height: 218px;
        border-radius: 18px;
        padding: 23px;
      }

      .feature-number {
        color: var(--purple-2);
        font-size: 0.84rem;
        font-weight: 900;
      }

      .band {
        margin: clamp(20px, 4vw, 38px) 0;
        border-radius: 28px;
        padding: clamp(28px, 5vw, 52px);
        background: linear-gradient(135deg, var(--purple), #276749);
        color: #ffffff;
      }

      .band h2,
      .band .kicker {
        color: #ffffff;
      }

      .band .section-copy {
        color: rgba(255, 255, 255, 0.84);
      }

      .kit-strip {
        display: grid;
        grid-template-columns: repeat(4, minmax(0, 1fr));
        gap: 16px;
        margin-top: 28px;
      }

      .kit-item {
        min-height: 170px;
        padding: 22px;
        border-radius: 22px;
        background: #ffffff;
        border: 1px solid rgba(75, 46, 131, 0.12);
        box-shadow: 0 18px 36px rgba(31, 41, 55, 0.08);
      }

      .kit-item:nth-child(1) {
        background: linear-gradient(135deg, #fdf2f8, #ffffff);
      }

      .kit-item:nth-child(2) {
        background: linear-gradient(135deg, #ede9fe, #ffffff);
      }

      .kit-item:nth-child(3) {
        background: linear-gradient(135deg, #ecfdf5, #ffffff);
      }

      .kit-item:nth-child(4) {
        background: linear-gradient(135deg, #fff7ed, #ffffff);
      }

      .kit-item strong {
        display: block;
        margin-bottom: 12px;
        color: var(--ink);
        font-size: 1.18rem;
        line-height: 1.15;
      }

      .kit-item span {
        display: block;
        color: var(--muted);
        font-size: 1rem;
        line-height: 1.65;
      }

      .bio {
        display: grid;
        grid-template-columns: 0.72fr 1.28fr;
        gap: 28px;
        align-items: start;
        border-radius: 24px;
        padding: 30px;
      }

      .bio-card {
        border-radius: 18px;
        background: linear-gradient(135deg, var(--lavender), var(--mint));
        padding: 24px;
        text-align: center;
      }

      .author-photo {
        display: block;
        width: min(270px, 100%);
        height: 250px;
        margin: 0 auto 18px;
        border-radius: 999px;
        object-fit: contain;
        border: 4px solid var(--purple-2);
        background: #000000;
        box-shadow: 0 14px 32px rgba(75, 46, 131, 0.18);
      }

      .bio-card strong {
        display: block;
        font-size: 1.35rem;
        margin-bottom: 18px;
      }

      .bio-card span {
        display: block;
        margin-top: 8px;
        color: var(--muted);
        line-height: 1.55;
      }

      .author-quote {
        margin-top: 20px;
        padding: 18px;
        border-radius: 16px;
        background: #ffffff;
        border: 1px solid var(--line);
        color: #7b2f72;
        font-family: Georgia, "Times New Roman", serif;
        font-style: italic;
        font-size: 1.05rem;
        line-height: 1.6;
      }

      .author-quote::before {
        content: "“";
      }

      .author-quote::after {
        content: "”";
      }

      .author-list {
        display: grid;
        gap: 16px;
        margin-top: 18px;
      }

      .author-list p {
        margin: 0;
      }

      .author-emphasis {
        color: var(--purple);
        font-weight: 800;
      }

      .kit-overview {
        display: grid;
        grid-template-columns: 1.1fr 0.9fr;
        gap: 22px;
        align-items: start;
      }

      .kit-main-image {
        width: 100%;
        border-radius: 24px;
        border: 1px solid var(--line);
        box-shadow: var(--shadow);
      }

      .resource-list {
        display: grid;
        gap: 12px;
      }

      .resource-list div {
        padding: 16px;
        border-radius: 16px;
        background: var(--surface);
        border: 1px solid var(--line);
      }

      .resource-list strong {
        display: block;
        color: var(--ink);
        margin-bottom: 5px;
      }

      .resource-list span {
        color: var(--muted);
        line-height: 1.55;
      }

      .video-frame {
        position: relative;
        overflow: hidden;
        border-radius: 24px;
        border: 1px solid var(--line);
        box-shadow: var(--shadow);
        background: #10101a;
        aspect-ratio: 16 / 9;
      }

      .video-frame iframe {
        position: absolute;
        inset: 0;
        width: 100%;
        height: 100%;
        border: 0;
      }

      .link-panel {
        padding: clamp(22px, 4vw, 34px);
        border-radius: 24px;
        background: linear-gradient(135deg, #f5ebff, #edf8f2);
        border: 1px solid var(--line);
        box-shadow: var(--shadow);
      }

      .link-panel h3 {
        margin: 0 0 8px;
        font-size: clamp(1.4rem, 3vw, 2rem);
      }

      .link-panel p {
        margin: 0 0 18px;
        color: var(--muted);
        line-height: 1.6;
      }

      .download-grid {
        display: grid;
        grid-template-columns: repeat(2, minmax(0, 1fr));
        gap: 18px;
      }

      .download-card {
        padding: 26px;
        border-radius: 22px;
        background: var(--surface);
        border: 1px solid var(--line);
        box-shadow: var(--shadow);
      }

      .download-card h3 {
        margin: 0 0 10px;
        font-size: 1.45rem;
      }

      .download-card .button {
        margin-top: 20px;
      }

      .showcase {
        display: grid;
        gap: 22px;
      }

      .showcase-hero,
      .showcase-card {
        overflow: hidden;
        background: #ffffff;
        border: 1px solid var(--line);
        box-shadow: var(--shadow);
      }

      .showcase-hero {
        border-radius: 28px;
      }

      .showcase-hero img {
        display: block;
        width: 100%;
        height: auto;
      }

      .showcase-grid {
        display: grid;
        grid-template-columns: repeat(3, minmax(0, 1fr));
        gap: 18px;
      }

      .showcase-card {
        border-radius: 22px;
      }

      .showcase-card img {
        display: block;
        width: 100%;
        aspect-ratio: 16 / 10;
        object-fit: cover;
        object-position: center;
        border-bottom: 1px solid var(--line);
      }

      .showcase-card.tall img {
        aspect-ratio: 9 / 13;
        object-position: top center;
      }

      .showcase-card.phone img {
        aspect-ratio: 9 / 16;
        object-position: top center;
      }

      .kit-gallery .showcase-card img {
        height: clamp(240px, 21vw, 340px);
        aspect-ratio: auto;
        padding: 14px;
        object-fit: contain;
        background: linear-gradient(135deg, #ffffff, #f8f6ff);
      }

      .kit-gallery .showcase-card.tall img {
        height: clamp(360px, 48vw, 620px);
      }

      .showcase-card.dark {
        background: #12111c;
        border-color: rgba(255, 255, 255, 0.12);
      }

      .showcase-card.dark .showcase-body h3,
      .showcase-card.dark .showcase-body p {
        color: #ffffff;
      }

      .showcase-body {
        padding: 18px;
      }

      .showcase-body h3 {
        margin: 0 0 8px;
        font-size: 1.1rem;
      }

      .showcase-body p {
        margin: 0;
        color: var(--muted);
        line-height: 1.62;
      }

      .notice {
        border-radius: 18px;
        padding: 22px;
        background: #fffaf0;
        border-color: #f0ddb2;
      }

      .privacy-list {
        display: grid;
        grid-template-columns: repeat(3, minmax(0, 1fr));
        gap: 14px;
        margin-top: 24px;
      }

      .privacy-list div {
        padding: 18px;
        border-radius: 16px;
        background: #ffffff;
        border: 1px solid var(--line);
      }

      .privacy-list strong {
        display: block;
        margin-bottom: 8px;
      }

      .privacy-list span {
        color: var(--muted);
        line-height: 1.6;
      }

      footer {
        padding: 34px 0 52px;
        color: var(--muted);
        text-align: center;
        font-size: 0.92rem;
      }

      .footer-social {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 12px;
        margin-top: 18px;
      }

      .social-link {
        display: inline-flex;
        align-items: center;
        gap: 8px;
        min-height: 42px;
        padding: 8px 12px;
        border: 1px solid rgba(75, 46, 131, 0.12);
        border-radius: 999px;
        background: #ffffff;
        color: var(--ink);
        font-size: 0.9rem;
        font-weight: 700;
        text-decoration: none;
        box-shadow: 0 10px 24px rgba(31, 41, 55, 0.06);
      }

      .social-link:hover {
        transform: translateY(-1px);
        border-color: rgba(124, 58, 237, 0.26);
        box-shadow: 0 14px 28px rgba(75, 46, 131, 0.1);
      }

      .social-link img {
        width: 24px;
        height: 24px;
        flex: 0 0 auto;
      }

      @media (max-width: 980px) {
        .hero,
        .product-grid,
        .feature-grid,
        .kit-strip,
        .bio,
        .kit-overview,
        .download-grid,
        .privacy-list,
        .showcase-grid {
          grid-template-columns: 1fr;
        }

        .app-preview {
          grid-template-columns: 1fr;
          text-align: center;
        }

        .app-preview img {
          margin: 0 auto;
        }

        .section-heading.with-icon {
          grid-template-columns: 1fr;
        }

        .heading-icon {
          width: min(70vw, 280px);
          margin: 0 auto;
        }

        .nav-inner {
          align-items: flex-start;
          flex-direction: column;
          padding: 18px 0;
        }

        .nav-links {
          justify-content: flex-start;
        }
      }

      @media (max-width: 560px) {
        .actions,
        .button,
        .product-actions {
          width: 100%;
        }

        .button {
          padding: 0 14px;
        }

        .hero-panel,
        .product,
        .bio {
          padding: 20px;
        }
      }