:root {
        --bg-main: #ffffff;
        --bg-gradient: #e2eefb;
        --card-bg: rgba(255, 255, 255, 0.85);
        --primary-blue: #0056b3;
        --light-blue: #e6f0fa;
        --dark-blue: #0a192f;
        --text-main: #1e293b;
        --text-light: #64748b;
        --border: rgba(0, 86, 179, 0.15);
        --shadow: 0 12px 35px rgba(0, 86, 179, 0.1);
        --nav-h: 64px;
      }

      * { margin: 0; padding: 0; box-sizing: border-box; }

      body {
        font-family: "DM Sans", system-ui, sans-serif;
        color: var(--text-main);
        line-height: 1.6;
        min-height: 100vh;
        overflow-x: hidden;
        background-color: var(--bg-main);
        background-image:
          radial-gradient(var(--border) 1px, transparent 1px),
          linear-gradient(135deg, var(--bg-main) 0%, var(--bg-gradient) 100%);
        background-size: 20px 20px, 100% 100%;
        background-attachment: fixed;
      }

      /* ─── BG ANIMATION ─── */
      .bg-animation {
        position: fixed; top: 0; left: 0;
        width: 100vw; height: 100vh;
        z-index: -1; overflow: hidden; pointer-events: none;
      }
      .math-shape {
        position: absolute; color: var(--primary-blue);
        opacity: 0; bottom: -100px;
        animation: floatUp linear infinite;
      }
      @keyframes floatUp {
        0%   { transform: translateY(0) rotate(0deg); opacity: 0; }
        10%  { opacity: 0.18; }
        90%  { opacity: 0.18; }
        100% { transform: translateY(-120vh) rotate(360deg); opacity: 0; }
      }
      .math-shape:nth-child(1)  { left: 10%; font-size: 2.5rem; animation-duration: 25s; animation-delay: 0s; }
      .math-shape:nth-child(2)  { left: 25%; font-size: 1.8rem; animation-duration: 20s; animation-delay: 5s; }
      .math-shape:nth-child(3)  { left: 40%; font-size: 3.5rem; animation-duration: 35s; animation-delay: 2s; }
      .math-shape:nth-child(4)  { left: 60%; font-size: 2rem;   animation-duration: 22s; animation-delay: 8s; }
      .math-shape:nth-child(5)  { left: 75%; font-size: 3rem;   animation-duration: 30s; animation-delay: 4s; }
      .math-shape:nth-child(6)  { left: 90%; font-size: 1.8rem; animation-duration: 18s; animation-delay: 1s; }
      .math-shape:nth-child(7)  { left: 15%; font-size: 2rem;   animation-duration: 28s; animation-delay: 12s; }
      .math-shape:nth-child(8)  { left: 85%; font-size: 2.8rem; animation-duration: 26s; animation-delay: 9s; }
      .math-shape:nth-child(9)  { left: 50%; font-size: 4rem;   animation-duration: 32s; animation-delay: 6s; }
      .math-shape:nth-child(10) { left: 35%; font-size: 1.6rem; animation-duration: 19s; animation-delay: 15s; }

      /* ─── NAVBAR ─── */
      .navbar {
        background: rgba(0, 86, 179, 0.97);
        backdrop-filter: blur(12px);
        -webkit-backdrop-filter: blur(12px);
        position: fixed; top: 0; width: 100%; z-index: 1000;
        height: var(--nav-h);
        padding: 0 5%;
        display: flex; align-items: center; justify-content: space-between;
        box-shadow: 0 2px 20px rgba(0,86,179,0.2);
      }
      .logo {
        display: flex; align-items: center; gap: 10px;
        font-family: "Sora", sans-serif;
        font-size: 20px; font-weight: 800;
        color: white; text-decoration: none;
        white-space: nowrap;
      }
      .logo i { font-size: 22px; }
      .nav-links {
        display: flex; gap: 28px; font-weight: 600;
      }
      .nav-links a {
        color: rgba(255,255,255,0.85); text-decoration: none;
        transition: color 0.2s; text-transform: uppercase;
        font-size: 0.8rem; letter-spacing: 1px;
      }
      .nav-links a:hover { color: white; }
      .hamburger {
        display: none; font-size: 22px; color: white;
        background: none; border: none; cursor: pointer;
        padding: 4px 8px; border-radius: 6px;
        transition: background 0.2s;
      }
      .hamburger:hover { background: rgba(255,255,255,0.15); }

      /* ─── MOBILE MENU ─── */
      .mobile-menu {
        display: none;
        position: fixed;
        top: var(--nav-h);
        left: 0; width: 100%;
        background: #0047a0;
        flex-direction: column;
        z-index: 998;
        box-shadow: 0 8px 24px rgba(0,0,0,0.15);
        border-top: 1px solid rgba(255,255,255,0.1);
        transform: translateY(-10px);
        opacity: 0;
        transition: all 0.25s ease;
      }
      .mobile-menu.active {
        display: flex;
        transform: translateY(0);
        opacity: 1;
      }
      .mobile-menu a {
        color: white; text-decoration: none;
        font-weight: 600; font-size: 0.95rem;
        text-transform: uppercase; letter-spacing: 0.8px;
        padding: 16px 24px;
        border-bottom: 1px solid rgba(255,255,255,0.08);
        display: flex; align-items: center; gap: 10px;
        transition: background 0.2s;
      }
      .mobile-menu a:last-child { border-bottom: none; }
      .mobile-menu a:hover { background: rgba(255,255,255,0.1); }
      .mobile-menu a i { width: 20px; text-align: center; opacity: 0.8; }

      /* ─── HERO ─── */
      .hero {
        padding: calc(var(--nav-h) + 60px) 5% 60px;
        text-align: center;
      }
      .badge {
        display: inline-flex; align-items: center; gap: 8px;
        background: rgba(230, 240, 250, 0.9);
        backdrop-filter: blur(4px);
        color: var(--primary-blue);
        padding: 8px 20px; border-radius: 50px;
        font-size: 12px; font-weight: 700;
        margin-bottom: 20px;
        border: 1px solid rgba(0, 86, 179, 0.2);
        letter-spacing: 0.5px;
      }
      .hero h1 {
        font-family: "Sora", sans-serif;
        font-size: clamp(2rem, 7vw, 3.6rem);
        font-weight: 800; line-height: 1.15;
        margin-bottom: 16px;
        max-width: 860px; margin-left: auto; margin-right: auto;
        letter-spacing: -0.02em; color: var(--dark-blue);
      }
      .hero h1 span { color: var(--primary-blue); }
      .hero p {
        font-size: clamp(0.95rem, 3.5vw, 1.2rem);
        color: var(--text-light);
        max-width: 600px; margin: 0 auto 36px;
        font-weight: 500;
      }
      .cta-buttons {
        display: flex; gap: 12px;
        justify-content: center; flex-wrap: wrap;
        padding: 0 16px;
      }
      .btn {
        padding: 14px 30px; border-radius: 50px;
        font-weight: 700; font-size: 0.88rem;
        text-transform: uppercase; letter-spacing: 1px;
        transition: all 0.3s cubic-bezier(0.4,0,0.2,1);
        text-decoration: none; display: inline-block;
        font-family: "Sora", sans-serif;
      }
      .btn-primary {
        background: var(--primary-blue); color: white;
        box-shadow: 0 6px 20px rgba(0,86,179,0.35);
      }
      .btn-primary:hover {
        transform: translateY(-3px);
        box-shadow: 0 10px 30px rgba(0,86,179,0.45);
        background: #004494;
      }
      .btn-secondary {
        background: rgba(255,255,255,0.6);
        backdrop-filter: blur(4px);
        color: var(--primary-blue);
        border: 2px solid var(--primary-blue);
      }
      .btn-secondary:hover { background: var(--light-blue); transform: translateY(-3px); }

      /* ─── CHALLENGE SECTION ─── */
      .challenge-section { padding: 20px 5% 80px; }

      .section-title {
        font-family: "Sora", sans-serif;
        font-size: clamp(1.8rem, 5vw, 2.4rem);
        font-weight: 800; margin-bottom: 8px;
        color: var(--dark-blue); text-align: center;
      }
      .section-subtitle {
        font-size: 1.1rem; color: var(--text-light);
        text-align: center; margin-bottom: 40px;
      }

      /* ─── GRID WRAP ─── */
      .grid-wrap { max-width: 1100px; margin: 0 auto; }

      .section-label {
        font-family: "Sora", sans-serif;
        font-size: 0.75rem; font-weight: 700;
        color: var(--primary-blue);
        margin: 36px 0 14px;
        padding-bottom: 8px;
        border-bottom: 2px solid var(--light-blue);
        text-transform: uppercase; letter-spacing: 1.5px;
      }

      .grid {
        display: grid;
        grid-template-columns: repeat(auto-fill, minmax(140px, 1fr));
        gap: 14px;
      }

      /* ─── CARD ─── */
      .card {
        background: var(--card-bg);
        backdrop-filter: blur(10px);
        -webkit-backdrop-filter: blur(10px);
        border: 1px solid rgba(255,255,255,0.5);
        border-radius: 18px;
        padding: 22px 12px 18px;
        text-decoration: none;
        display: flex; flex-direction: column;
        align-items: center; gap: 10px;
        transition: all 0.3s cubic-bezier(0.4,0,0.2,1);
        box-shadow: 0 4px 16px rgba(0,40,90,0.05);
        cursor: pointer;
        /* Tap highlight fix for mobile */
        -webkit-tap-highlight-color: transparent;
      }
      .card:hover, .card:active {
        transform: translateY(-4px);
        background: #ffffff;
        box-shadow: var(--shadow);
        border-color: rgba(0,86,179,0.3);
      }
      .card:active { transform: scale(0.97); }

      .card-icon {
        width: 52px; height: 52px;
        border-radius: 14px;
        display: flex; align-items: center; justify-content: center;
        font-size: 20px;
        transition: transform 0.3s ease;
        flex-shrink: 0;
      }
      .card:hover .card-icon,
      .card:active .card-icon { transform: scale(1.08); }

      .card-label {
        font-weight: 700;
        color: var(--dark-blue);
        font-size: 0.88rem;
        text-align: center;
        line-height: 1.3;
      }

      /* Icon Color Themes */
      .ic-amber   { background: #fffbeb; color: #d97706; }
      .ic-sky     { background: #f0f9ff; color: #0284c7; }
      .ic-purple  { background: #faf5ff; color: #9333ea; }
      .ic-emerald { background: #ecfdf5; color: #059669; }
      .ic-rose    { background: #fff1f2; color: #e11d48; }
      .ic-indigo  { background: #eef2ff; color: #4f46e5; }

      .card-logout { border: 1px dashed #fda4af; }

      /* ═══════════════════════════════════
         MOBILE STYLES — the main fixes
      ═══════════════════════════════════ */

      /* Tablet */
      @media (max-width: 768px) {
        :root { --nav-h: 60px; }

        .hamburger { display: block; }
        .nav-links  { display: none; }

        .hero { padding: calc(var(--nav-h) + 40px) 20px 48px; }
        .hero p { padding: 0 8px; }

        .cta-buttons { gap: 10px; }
        .btn { padding: 13px 26px; font-size: 0.82rem; }

        .challenge-section { padding: 12px 16px 60px; }

        .grid-wrap { padding: 0; }

        .section-label { margin: 28px 0 12px; }

        .grid {
          grid-template-columns: repeat(3, 1fr);
          gap: 10px;
        }

        .card { padding: 16px 8px 14px; border-radius: 14px; gap: 8px; }
        .card-icon { width: 46px; height: 46px; font-size: 18px; border-radius: 12px; }
        .card-icon svg { width: 20px; height: 20px; }
        .card-label { font-size: 0.82rem; }
      }

      /* Mobile Phone */
      @media (max-width: 480px) {
        :root { --nav-h: 58px; }

        .logo { font-size: 18px; }
        .logo i { font-size: 20px; }

        .hero { padding: calc(var(--nav-h) + 28px) 16px 40px; }

        .badge { font-size: 11px; padding: 7px 16px; }

        .cta-buttons { flex-direction: column; gap: 10px; align-items: stretch; }
        .btn { text-align: center; padding: 15px 20px; font-size: 0.85rem; }

        .challenge-section { padding: 8px 14px 50px; }

        .section-title { margin-bottom: 6px; }
        .section-subtitle { font-size: 0.95rem; margin-bottom: 28px; }

        .grid {
          grid-template-columns: repeat(3, 1fr);
          gap: 9px;
        }

        /* Cards with longer labels get slightly more room */
        .card { padding: 14px 6px 12px; border-radius: 12px; gap: 7px; }
        .card-icon { width: 42px; height: 42px; font-size: 16px; border-radius: 10px; }
        .card-icon svg { width: 18px; height: 18px; }
        .card-label { font-size: 0.78rem; }
      }

      /* Very small phones */
      @media (max-width: 360px) {
        .grid {
          grid-template-columns: repeat(2, 1fr);
          gap: 10px;
        }
        .card { padding: 16px 10px 14px; border-radius: 14px; }
        .card-icon { width: 44px; height: 44px; }
        .card-label { font-size: 0.82rem; }
      }