/* =====================================================
       CSS CUSTOM PROPERTIES
    ===================================================== */
    :root {
      /* Subject Colors */
      --math: #4361EE;
      --math-dark: #3451D1;
      --english: #2DC653;
      --english-dark: #24A845;
      --science: #F4A261;
      --history: #E63946;
      --general: #7B2D8B;

      /* Neutrals */
      --bg: #FDFAF4;
      --bg-alt: #F0EBE0;
      --ink: #1A1A2E;
      --ink-light: #2D2D4A;
      --muted: #6B7280;
      --border: rgba(26, 26, 46, 0.12);
      --white: #FFFFFF;

      /* Typography */
      --font-display: 'Baloo 2', sans-serif;
      --font-body: 'Lato', sans-serif;
      --font-accent: 'Righteous', cursive;

      /* Spacing */
      --space-xs: 4px;
      --space-sm: 8px;
      --space-md: 16px;
      --space-lg: 24px;
      --space-xl: 40px;
      --space-2xl: 64px;
      --space-3xl: 96px;

      /* Radius */
      --radius-sm: 8px;
      --radius-md: 16px;
      --radius-lg: 24px;
      --radius-pill: 100px;

      /* Shadows */
      --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.06);
      --shadow-md: 0 4px 20px rgba(0, 0, 0, 0.08);
      --shadow-lg: 0 8px 40px rgba(0, 0, 0, 0.12);
      --shadow-hover: 0 12px 40px rgba(0, 0, 0, 0.15);

      /* Transitions */
      --transition: 0.25s ease;
    }

    /* =====================================================
       RESET & BASE
    ===================================================== */
    *, *::before, *::after {
      box-sizing: border-box;
      margin: 0;
      padding: 0;
    }

    html {
      scroll-behavior: smooth;
    }

    body {
      font-family: var(--font-body);
      background-color: var(--bg);
      color: var(--ink);
      line-height: 1.6;
      /* Notebook paper: subtle horizontal lines + diagonal weave */
      background-image:
        repeating-linear-gradient(
          -45deg,
          transparent,
          transparent 24px,
          rgba(170, 158, 138, 0.07) 24px,
          rgba(170, 158, 138, 0.07) 25px
        ),
        repeating-linear-gradient(
          to bottom,
          transparent,
          transparent 31px,
          rgba(100, 140, 220, 0.045) 31px,
          rgba(100, 140, 220, 0.045) 32px
        );
      min-height: 100vh;
      overflow-x: hidden;
    }

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

    button {
      cursor: pointer;
      border: none;
      background: none;
      font-family: inherit;
    }

    ul { list-style: none; }

    /* =====================================================
       TYPOGRAPHY
    ===================================================== */
    h1, h2, h3, h4 {
      font-family: var(--font-display);
      font-weight: 800;
      line-height: 1.2;
    }

    /* =====================================================
       KEYFRAME ANIMATIONS
    ===================================================== */
    @keyframes fadeInUp {
      from { opacity: 0; transform: translateY(30px); }
      to   { opacity: 1; transform: translateY(0); }
    }

    @keyframes slideInScale {
      from { opacity: 0; transform: translateY(20px) scale(0.95); }
      to   { opacity: 1; transform: translateY(0)   scale(1); }
    }

    @keyframes float {
      0%, 100% { transform: translateY(0) rotate(0deg); }
      50%       { transform: translateY(-18px) rotate(4deg); }
    }

    @keyframes floatReverse {
      0%, 100% { transform: translateY(0) rotate(0deg); }
      50%       { transform: translateY(-14px) rotate(-6deg); }
    }

    @keyframes drift {
      0%   { transform: translate(0, 0) rotate(0deg); }
      33%  { transform: translate(8px, -14px) rotate(16deg); }
      66%  { transform: translate(-6px, -8px) rotate(-10deg); }
      100% { transform: translate(0, 0) rotate(0deg); }
    }

    @keyframes bounceArrow {
      0%, 100% { transform: translateY(0) translateX(-50%); }
      50%       { transform: translateY(10px) translateX(-50%); }
    }

    @keyframes toastIn {
      from { transform: translateY(80px); opacity: 0; }
      to   { transform: translateY(0);    opacity: 1; }
    }

    @keyframes toastOut {
      from { transform: translateY(0);    opacity: 1; }
      to   { transform: translateY(80px); opacity: 0; }
    }

    .animate-fade-in-up   { animation: fadeInUp    0.65s ease both; }
    .animate-slide-in-scale { animation: slideInScale 0.4s ease both; }

    /* =====================================================
       LAYOUT
    ===================================================== */
    .container {
      max-width: 1100px;
      margin: 0 auto;
      padding: 0 var(--space-lg);
    }

    .section { padding: var(--space-3xl) 0; }

    .section-label {
      display: inline-block;
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 0.72rem;
      letter-spacing: 0.13em;
      text-transform: uppercase;
      color: #4361EE;
      background: rgba(67, 97, 238, 0.09);
      padding: 4px 14px;
      border-radius: var(--radius-pill);
      margin-bottom: var(--space-md);
    }

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

    /* =====================================================
       NAVBAR
    ===================================================== */
    .navbar {
      position: sticky;
      top: 0;
      z-index: 100;
      /* needed so the mobile dropdown is anchored to the navbar */
      background: rgba(26, 26, 46, 0.93);
      backdrop-filter: blur(8px);
      -webkit-backdrop-filter: blur(8px);
      border-bottom: 1px solid rgba(255, 255, 255, 0.07);
      padding: 8px 0;
    }

    .navbar__inner {
      display: flex;
      align-items: center;
      justify-content: space-between;
      gap: var(--space-lg);
    }

    .navbar__brand {
      display: flex;
      align-items: center;
      gap: 10px;
      text-decoration: none;
    }

    .navbar__name-wrap {
      display: flex;
      flex-direction: column;
    }

    .navbar__name {
      font-family: var(--font-display);
      font-weight: 800;
      font-size: 1.35rem;
      color: var(--white);
      line-height: 1;
      letter-spacing: -0.01em;
    }

    .navbar__tagline {
      font-family: var(--font-body);
      font-style: italic;
      font-size: 0.68rem;
      color: rgba(255, 255, 255, 0.48);
      line-height: 1;
      margin-top: 2px;
    }

    .navbar__right {
      display: flex;
      align-items: center;
      gap: var(--space-md);
    }

    .navbar__link {
      font-family: var(--font-display);
      font-weight: 600;
      font-size: 0.88rem;
      color: rgba(255, 255, 255, 0.78);
      padding: 5px 12px;
      border-radius: var(--radius-sm);
      transition: color var(--transition), background var(--transition);
    }

    .navbar__link:hover {
      color: var(--white);
      background: rgba(255, 255, 255, 0.08);
    }

    .navbar__badge {
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 0.72rem;
      color: var(--ink);
      background: linear-gradient(135deg, #FFD166, #FFC233);
      padding: 4px 10px;
      border-radius: var(--radius-pill);
      white-space: nowrap;
    }

    /* =====================================================
       HERO
    ===================================================== */
    .hero {
      position: relative;
      padding: 16px 0 20px;
      text-align: center;
      overflow: hidden;
    }

    /* Floating background shapes */
    .hero__bg-shapes {
      position: absolute;
      inset: 0;
      pointer-events: none;
      z-index: 0;
    }

    .hero__shape {
      position: absolute;
      opacity: 0.4;
    }

    .hero__shape--1 {
      width: 80px; height: 80px;
      background: rgba(67, 97, 238, 0.14);
      border-radius: 50%;
      top: 12%; left: 7%;
      animation: drift 9s ease-in-out infinite;
    }

    .hero__shape--2 {
      width: 48px; height: 48px;
      background: rgba(45, 198, 83, 0.14);
      border-radius: 12px;
      top: 28%; right: 9%;
      animation: drift 6.5s ease-in-out infinite 1s;
    }

    .hero__shape--3 {
      width: 110px; height: 110px;
      background: rgba(244, 162, 97, 0.1);
      border-radius: 50%;
      bottom: 18%; left: 4%;
      animation: drift 11s ease-in-out infinite 2s;
    }

    .hero__shape--4 {
      width: 58px; height: 58px;
      background: rgba(230, 57, 70, 0.09);
      border-radius: 30% 70% 70% 30% / 30% 30% 70% 70%;
      top: 8%; right: 22%;
      animation: drift 7.5s ease-in-out infinite 0.5s;
    }

    .hero__shape--5 {
      width: 38px; height: 38px;
      background: rgba(123, 45, 139, 0.11);
      border-radius: 4px;
      bottom: 28%; right: 6%;
      transform: rotate(45deg);
      animation: drift 8.5s ease-in-out infinite 3s;
    }

    .hero__shape--6 {
      width: 28px; height: 28px;
      background: rgba(67, 97, 238, 0.1);
      clip-path: polygon(50% 0%, 61% 35%, 98% 35%, 68% 57%, 79% 91%, 50% 70%, 21% 91%, 32% 57%, 2% 35%, 39% 35%);
      top: 48%; left: 14%;
      animation: drift 5.5s ease-in-out infinite 1.5s;
    }

    .hero__content {
      position: relative;
      z-index: 1;
    }

    /* Decorative row: books | heading+sub | pencil */
    .hero__decorations {
      display: flex;
      align-items: center;
      justify-content: center;
      gap: var(--space-xl);
      margin-bottom: var(--space-md);
    }

    .hero__center { flex: 1; min-width: 0; }

    /* CSS Books Stack */
    .books-stack {
      display: flex;
      flex-direction: column-reverse;
      gap: 4px;
      align-items: flex-start;
      animation: float 5.5s ease-in-out infinite;
    }

    .book {
      height: 14px;
      border-radius: 3px 6px 6px 3px;
      position: relative;
    }

    .book::before {
      content: '';
      position: absolute;
      left: 0; top: 0; bottom: 0;
      width: 8px;
      background: rgba(0, 0, 0, 0.16);
      border-radius: 3px 0 0 3px;
    }

    .book--1 { width: 72px;  background: #4361EE; }
    .book--2 { width: 60px;  background: #2DC653; }
    .book--3 { width: 78px;  background: #F4A261; }
    .book--4 { width: 54px;  background: #E63946; }
    .book--5 { width: 66px;  background: #7B2D8B; }

    /* CSS Pencil */
    .pencil-cluster {
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: var(--space-sm);
      animation: floatReverse 6s ease-in-out infinite;
    }

    .star-cluster {
      display: flex;
      gap: 5px;
      align-items: center;
    }

    .star { display: inline-block; animation: drift 3.5s ease-in-out infinite; }
    .star:nth-child(1) { font-size: 1.2rem; }
    .star:nth-child(2) { font-size: 0.85rem; animation-delay: 0.6s; }
    .star:nth-child(3) { font-size: 1.4rem;  animation-delay: 1.1s; }

    .hero__heading {
      font-size: clamp(1.6rem, 4vw, 2.6rem);
      color: var(--ink);
      margin-bottom: var(--space-sm);
      animation: fadeInUp 0.7s ease both;
    }

    .hero__heading span { color: #4361EE; }

    .hero__subheading {
      font-size: clamp(0.9rem, 2vw, 1.05rem);
      color: var(--muted);
      max-width: 520px;
      margin: 0 auto var(--space-md);
      font-weight: 400;
      animation: fadeInUp 0.7s ease 0.15s both;
    }

    .hero__scroll-indicator {
      position: absolute;
      bottom: var(--space-lg);
      left: 50%;
      animation: bounceArrow 2.2s ease-in-out infinite;
      display: flex;
      flex-direction: column;
      align-items: center;
      gap: 4px;
      color: var(--muted);
    }

    .hero__scroll-text {
      font-family: var(--font-display);
      font-size: 0.68rem;
      font-weight: 700;
      letter-spacing: 0.11em;
      text-transform: uppercase;
      white-space: nowrap;
    }

    /* =====================================================
       GRADE SELECTOR
    ===================================================== */
    .grade-selector {
      padding: var(--space-xl) 0 var(--space-2xl);
      text-align: center;
      animation: fadeInUp 0.7s ease 0.28s both;
    }

    .grade-selector__inner {
      background: var(--white);
      border-radius: var(--radius-lg);
      padding: var(--space-xl);
      box-shadow: var(--shadow-md);
      max-width: 700px;
      margin: 0 auto;
    }

    .grade-selector__step {
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 0.72rem;
      letter-spacing: 0.13em;
      text-transform: uppercase;
      color: #4361EE;
      display: flex;
      align-items: center;
      justify-content: center;
      gap: 10px;
      margin-bottom: var(--space-md);
    }

    .grade-selector__step::before,
    .grade-selector__step::after {
      content: '';
      height: 1px;
      width: 36px;
      background: rgba(67, 97, 238, 0.22);
    }

    .grade-selector__title {
      font-size: 1.35rem;
      color: var(--ink);
      margin-bottom: var(--space-lg);
    }

    /* Grade Pills (Desktop) */
    .grade-pills {
      display: flex;
      flex-wrap: wrap;
      gap: var(--space-sm);
      justify-content: center;
      margin-bottom: var(--space-md);
    }

    .grade-pill {
      font-family: var(--font-accent);
      font-size: 1rem;
      width: 48px;
      height: 48px;
      border-radius: var(--radius-pill);
      border: 2px solid var(--border);
      color: var(--ink-light);
      background: var(--bg);
      transition: all var(--transition);
      display: flex;
      align-items: center;
      justify-content: center;
    }

    .grade-pill:hover {
      border-color: #4361EE;
      color: #4361EE;
      background: rgba(67, 97, 238, 0.06);
      transform: translateY(-2px);
    }

    .grade-pill.active {
      background: #4361EE;
      border-color: #4361EE;
      color: var(--white);
      box-shadow: 0 4px 14px rgba(67, 97, 238, 0.38);
      transform: translateY(-2px);
    }

    /* Grade Select Dropdown (Mobile) */
    .grade-select-wrap {
      position: relative;
      display: none;
    }

    .grade-select {
      width: 100%;
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 1rem;
      color: var(--ink);
      background: var(--bg);
      border: 2px solid var(--border);
      border-radius: var(--radius-md);
      padding: 14px 48px 14px 20px;
      appearance: none;
      -webkit-appearance: none;
      cursor: pointer;
      transition: border-color var(--transition), box-shadow var(--transition);
    }

    .grade-select:focus {
      outline: none;
      border-color: #4361EE;
      box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.15);
    }

    .grade-select-wrap::after {
      content: '';
      position: absolute;
      right: 18px;
      top: 50%;
      transform: translateY(-50%);
      width: 0; height: 0;
      border-left: 6px solid transparent;
      border-right: 6px solid transparent;
      border-top: 7px solid #4361EE;
      pointer-events: none;
    }

    /* =====================================================
       SUBJECTS SECTION
    ===================================================== */
    .subjects-section {
      padding: 0 0 var(--space-2xl);
      display: none;
    }

    .subjects-section.visible {
      display: block;
    }

    .subjects-header {
      text-align: center;
      margin-bottom: var(--space-xl);
    }

    .subjects-title {
      font-size: 1.8rem;
      color: var(--ink);
    }

    .subjects-grid {
      display: grid;
      grid-template-columns: 1fr;
      gap: var(--space-lg);
    }

    /* Subject Card */
    .subject-card {
      background: var(--white);
      border-radius: var(--radius-md);
      box-shadow: var(--shadow-md);
      border-left: 6px solid var(--subject-color, var(--general));
      overflow: hidden;
      transition: box-shadow var(--transition), transform var(--transition);
    }

    .subject-card:hover {
      box-shadow: var(--shadow-hover);
    }

    .subject-card.active {
      box-shadow: var(--shadow-hover);
    }

    .subject-card__button {
      width: 100%;
      display: flex;
      align-items: center;
      gap: var(--space-md);
      padding: var(--space-lg) var(--space-xl);
      text-align: left;
      cursor: pointer;
      background: none;
      border: none;
      font-family: inherit;
      transition: background var(--transition);
    }

    .subject-card__button:hover {
      background: rgba(0, 0, 0, 0.02);
    }

    .subject-card__button:focus-visible {
      outline: 3px solid var(--subject-color, var(--general));
      outline-offset: -3px;
    }

    .subject-card.active .subject-card__button {
      border-bottom: 2px solid rgba(0, 0, 0, 0.06);
    }

    .subject-card__icon {
      font-size: 2.2rem;
      flex-shrink: 0;
      line-height: 1;
    }

    .subject-card__info { flex: 1; }

    .subject-card__name {
      font-family: var(--font-display);
      font-weight: 800;
      font-size: 1.15rem;
      color: var(--ink);
      line-height: 1.2;
    }

    .subject-card__desc {
      font-size: 0.84rem;
      color: var(--muted);
      margin-top: 3px;
    }

    .subject-card__chevron {
      flex-shrink: 0;
      width: 30px; height: 30px;
      border-radius: 50%;
      background: rgba(0, 0, 0, 0.06);
      display: flex;
      align-items: center;
      justify-content: center;
      transition: transform var(--transition), background var(--transition);
      color: var(--muted);
    }

    .subject-card.active .subject-card__chevron {
      transform: rotate(180deg);
      background: var(--subject-color, var(--general));
      color: var(--white);
    }

    /* Topics Panel */
    .topics-panel {
      overflow: hidden;
      max-height: 0;
      opacity: 0;
      transition: max-height 0.45s ease, opacity 0.3s ease;
    }

    .topics-panel.open {
      max-height: 2000px;
      opacity: 1;
    }

    .topics-panel__inner {
      padding: var(--space-md) var(--space-xl) var(--space-xl);
    }

    .topics-header {
      display: flex;
      align-items: center;
      gap: var(--space-sm);
      margin-bottom: var(--space-md);
      padding-bottom: var(--space-sm);
      border-bottom: 1px solid var(--border);
    }

    .topics-header__label {
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 0.68rem;
      letter-spacing: 0.13em;
      text-transform: uppercase;
      color: var(--muted);
    }

    .topics-list {
      display: flex;
      flex-direction: column;
      gap: 6px;
    }

    /* Topic Row */
    .topic-row {
      display: flex;
      align-items: center;
      gap: var(--space-md);
      padding: 10px var(--space-md);
      border-radius: var(--radius-sm);
      background: var(--bg);
      opacity: 0;
      transform: translateY(10px);
      transition: background var(--transition), opacity 0.3s ease, transform 0.3s ease;
    }

    .topic-row.animated {
      opacity: 1;
      transform: translateY(0);
    }

    .topic-row:hover {
      background: rgba(0, 0, 0, 0.028);
    }

    .topic-row__number {
      font-family: var(--font-accent);
      font-size: 0.82rem;
      color: var(--muted);
      min-width: 22px;
      text-align: right;
      flex-shrink: 0;
    }

    .topic-row__name {
      font-family: var(--font-display);
      font-weight: 600;
      font-size: 0.94rem;
      color: var(--ink);
      flex: 1;
    }

    .topic-row__actions {
      display: flex;
      align-items: center;
      gap: var(--space-sm);
      flex-shrink: 0;
    }

    .coming-soon-badge {
      font-size: 0.68rem;
      font-family: var(--font-display);
      font-weight: 600;
      color: var(--muted);
      background: var(--bg-alt);
      border: 1px solid var(--border);
      padding: 2px 8px;
      border-radius: var(--radius-pill);
      white-space: nowrap;
    }

    /* =====================================================
       BUTTONS
    ===================================================== */
    .btn {
      display: inline-flex;
      align-items: center;
      gap: 5px;
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 0.8rem;
      padding: 7px 14px;
      border-radius: var(--radius-pill);
      border: 2px solid transparent;
      transition: all var(--transition);
      text-decoration: none;
      white-space: nowrap;
      cursor: pointer;
    }

    /* Outlined pill — Guide */
    .btn-guide {
      border-color: var(--subject-color, var(--general));
      color: var(--subject-color, var(--general));
      background: transparent;
    }

    .btn-guide:not(.coming-soon):hover {
      background: var(--subject-color, var(--general));
      color: var(--white);
      transform: translateY(-1px);
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.14);
    }

    /* Solid fill — Worksheet */
    .btn-worksheet {
      background: var(--subject-color, var(--general));
      color: var(--white);
      border-color: var(--subject-color, var(--general));
    }

    .btn-worksheet:not(.coming-soon):hover {
      filter: brightness(0.88);
      transform: translateY(-1px);
      box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
    }

    /* Coming-soon state */
    .btn.coming-soon {
      opacity: 0.52;
      cursor: not-allowed;
      position: relative;
    }

    /* Tooltip on hover for coming-soon */
    .btn.coming-soon::after {
      content: attr(data-tooltip);
      position: absolute;
      bottom: calc(100% + 8px);
      left: 50%;
      transform: translateX(-50%);
      background: var(--ink);
      color: var(--white);
      font-size: 0.7rem;
      font-weight: 400;
      padding: 5px 10px;
      border-radius: var(--radius-sm);
      white-space: nowrap;
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.2s ease;
      z-index: 20;
    }

    .btn.coming-soon::before {
      content: '';
      position: absolute;
      bottom: calc(100% + 3px);
      left: 50%;
      transform: translateX(-50%);
      border: 5px solid transparent;
      border-top-color: var(--ink);
      opacity: 0;
      pointer-events: none;
      transition: opacity 0.2s ease;
    }

    .btn.coming-soon:hover::after,
    .btn.coming-soon:hover::before {
      opacity: 1;
    }

    /* =====================================================
       HOW IT WORKS
    ===================================================== */
    .how-it-works {
      background: var(--bg-alt);
      padding: var(--space-3xl) 0;
      position: relative;
    }

    .how-it-works::before {
      content: '';
      position: absolute;
      top: 0; left: 0; right: 0;
      height: 2px;
      background: linear-gradient(90deg, transparent, rgba(26, 26, 46, 0.1), transparent);
    }

    .how-it-works__header {
      text-align: center;
      margin-bottom: var(--space-2xl);
    }

    .how-it-works__title {
      font-size: clamp(1.55rem, 3vw, 2.1rem);
      color: var(--ink);
    }

    .how-it-works__subtitle {
      color: var(--muted);
      margin-top: var(--space-sm);
    }

    .steps-grid {
      display: grid;
      grid-template-columns: repeat(3, 1fr);
      gap: var(--space-lg);
    }

    .step-card {
      background: var(--white);
      border-radius: var(--radius-md);
      padding: var(--space-xl) var(--space-lg);
      box-shadow: var(--shadow-sm);
      text-align: center;
      position: relative;
      overflow: hidden;
      transition: box-shadow var(--transition), transform var(--transition);
    }

    .step-card:hover {
      box-shadow: var(--shadow-md);
      transform: translateY(-4px);
    }

    .step-card__number {
      font-family: var(--font-accent);
      font-size: 5.5rem;
      color: rgba(67, 97, 238, 0.055);
      position: absolute;
      top: -14px;
      right: 8px;
      line-height: 1;
      user-select: none;
    }

    .step-card__icon {
      font-size: 2.5rem;
      margin-bottom: var(--space-md);
      display: block;
    }

    .step-card__title {
      font-family: var(--font-display);
      font-weight: 800;
      font-size: 1.1rem;
      color: var(--ink);
      margin-bottom: var(--space-sm);
    }

    .step-card__desc {
      font-size: 0.88rem;
      color: var(--muted);
      line-height: 1.65;
    }

    /* =====================================================
       FOOTER WAVE
    ===================================================== */
    .footer-wave {
      display: block;
      width: 100%;
      overflow: hidden;
      line-height: 0;
      transform: scaleX(-1);
      margin-bottom: -2px;
    }

    /* =====================================================
       FOOTER
    ===================================================== */
    .footer {
      background: var(--ink);
      color: rgba(255, 255, 255, 0.72);
      padding: var(--space-2xl) 0 var(--space-lg);
    }

    .footer__inner {
      display: grid;
      grid-template-columns: 1fr auto 1fr;
      gap: var(--space-xl);
      align-items: start;
      margin-bottom: var(--space-xl);
    }

    .footer__brand .navbar__name {
      font-size: 1.18rem;
      margin-bottom: 4px;
    }

    .footer__tagline {
      font-style: italic;
      font-size: 0.82rem;
      color: rgba(255, 255, 255, 0.38);
      margin-top: 4px;
    }

    .footer__links { text-align: center; }

    .footer__links-label {
      font-family: var(--font-display);
      font-weight: 700;
      font-size: 0.7rem;
      letter-spacing: 0.11em;
      text-transform: uppercase;
      color: rgba(255, 255, 255, 0.38);
      margin-bottom: var(--space-sm);
    }

    .footer__links-list {
      display: flex;
      flex-wrap: wrap;
      gap: 4px var(--space-sm);
      justify-content: center;
    }

    .footer__links-list li a {
      font-family: var(--font-display);
      font-weight: 600;
      font-size: 0.78rem;
      color: rgba(255, 255, 255, 0.52);
      padding: 2px 5px;
      transition: color var(--transition);
    }

    .footer__links-list li a:hover { color: var(--white); }

    .footer__links-list li:not(:last-child)::after {
      content: '·';
      color: rgba(255, 255, 255, 0.2);
      margin-left: var(--space-sm);
      display: inline-block;
    }

    .footer__right { text-align: right; }

    .footer__heart {
      font-size: 0.88rem;
      line-height: 1.6;
      margin-bottom: var(--space-sm);
    }

    .footer__github {
      font-size: 0.73rem;
      color: rgba(255, 255, 255, 0.32);
      display: flex;
      align-items: center;
      gap: 5px;
      justify-content: flex-end;
    }

    .footer__bottom {
      border-top: 1px solid rgba(255, 255, 255, 0.07);
      padding-top: var(--space-lg);
      text-align: center;
      font-size: 0.76rem;
      color: rgba(255, 255, 255, 0.28);
    }

    /* =====================================================
       BURGER MENU
    ===================================================== */
    .navbar__burger {
      display: none;
      flex-direction: column;
      justify-content: center;
      gap: 5px;
      background: none;
      border: none;
      cursor: pointer;
      padding: 8px;
      border-radius: var(--radius-sm);
      transition: background var(--transition);
    }

    .navbar__burger:hover { background: rgba(255,255,255,.1); }

    .navbar__burger span {
      display: block;
      width: 22px;
      height: 2px;
      background: var(--white);
      border-radius: 2px;
      transition: transform 0.25s ease, opacity 0.25s ease;
      pointer-events: none;
    }

    .navbar__burger.is-open span:nth-child(1) { transform: translateY(7px) rotate(45deg); }
    .navbar__burger.is-open span:nth-child(2) { opacity: 0; transform: scaleX(0); }
    .navbar__burger.is-open span:nth-child(3) { transform: translateY(-7px) rotate(-45deg); }

    /* =====================================================
       TOAST NOTIFICATIONS
    ===================================================== */
    .toast-container {
      position: fixed;
      bottom: var(--space-xl);
      left: 50%;
      transform: translateX(-50%);
      z-index: 1000;
      display: flex;
      flex-direction: column;
      gap: var(--space-sm);
      align-items: center;
      pointer-events: none;
    }

    .toast {
      background: var(--ink);
      color: var(--white);
      font-family: var(--font-display);
      font-weight: 600;
      font-size: 0.9rem;
      padding: 12px 26px;
      border-radius: var(--radius-pill);
      box-shadow: var(--shadow-lg);
      animation: toastIn 0.35s ease both;
      pointer-events: auto;
      max-width: 90vw;
      text-align: center;
    }

    .toast.dismissing {
      animation: toastOut 0.35s ease both;
    }

    /* =====================================================
       RESPONSIVE — TABLET
    ===================================================== */
    @media (max-width: 900px) {
      .steps-grid {
        grid-template-columns: 1fr;
        max-width: 480px;
        margin: 0 auto;
      }
    }

    /* =====================================================
       RESPONSIVE — MOBILE
    ===================================================== */
    @media (max-width: 768px) {
      /* Hide pills, show dropdown */
      .grade-pills         { display: none; }
      .grade-select-wrap   { display: block; }

      /* Sticky grade selector bar */
      .grade-selector {
        position: sticky;
        top: 56px;
        z-index: 50;
        padding: var(--space-md) 0;
        background: var(--bg);
        box-shadow: var(--shadow-sm);
      }

      .grade-selector__inner {
        padding: var(--space-md) var(--space-lg);
        border-radius: var(--radius-sm);
      }

      /* Footer stacks */
      .footer__inner {
        grid-template-columns: 1fr;
        text-align: center;
      }

      .footer__right  { text-align: center; }
      .footer__github { justify-content: center; }

      /* Topic rows wrap */
      .topic-row { flex-wrap: wrap; }

      .topic-row__actions {
        flex-direction: column;
        width: 100%;
        padding-left: calc(22px + var(--space-md));
        gap: 6px;
      }

      .btn { width: 100%; justify-content: center; }

      /* Hero */
      .hero__decoration--books  { display: none; }
      .hero__decoration--pencil { display: none; }

      /* Navbar — burger */
      .navbar__tagline { display: none; }
      .navbar__badge   { display: none; }
      .navbar__burger  { display: flex; }

      .navbar__right {
        display: none;
        flex-direction: column;
        position: absolute;
        left: 0; right: 0;
        top: 100%;
        background: var(--ink);
        border-bottom: 1px solid rgba(255,255,255,.1);
        padding: 8px 24px 20px;
        z-index: 99;
        gap: 2px;
        box-shadow: 0 6px 24px rgba(0,0,0,.35);
      }

      .navbar__right.nav-open { display: flex; }
      .navbar__right .navbar__link { padding: 12px 0; width: 100%; }
    }

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