@font-face {
            font-family: "BRoya";
            src: url("/fonts/BRoya.ttf") format("truetype");
            font-weight: 400;
        }

        @font-face {
            font-family: "BRoya";
            src: url("/fonts/BRoyaBold.ttf") format("truetype");
            font-weight: 700 950;
        }

        :root {
            --blue: #0b63e5;
            --blue-dark: #0645a9;
            --ink: #10223d;
            --muted: #66758a;
            --line: #dce6f1;
            --paper: #ffffff;
            --bg: #f8fbff;
            --amber: #f8b719;
            --green: #1aa35f;
            --red: #ef3d2f;
            --teal: #0b5964;
        }

        * { box-sizing: border-box; }

        body {
            margin: 0;
            background: var(--bg);
            color: var(--ink);
            font-family: "BRoya", Tahoma, Arial, sans-serif;
            letter-spacing: 0;
        }

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

        button, input { font: inherit; }

        .shell {
            max-width: 1760px;
            margin: 0 auto;
            padding: 0 50px 36px;
        }

        .topbar {
            height: 80px;
            display: grid;
            grid-template-columns: auto 1fr auto auto auto;
            align-items: center;
            gap: 28px;
            padding: 0 64px;
            background: rgba(255, 255, 255, .98);
            border-bottom: 1px solid var(--line);
            box-shadow: 0 2px 14px rgba(16, 34, 61, .06);
        }

        .brand {
            display: inline-flex;
            align-items: center;
            gap: 14px;
            color: #0954c4;
            font-size: 33px;
            font-weight: 950;
            white-space: nowrap;
        }

        .brand-mark {
            width: 54px;
            height: 54px;
            display: grid;
            place-items: center;
            border-radius: 17px;
            color: #fff;
            font-family: Georgia, serif;
            font-size: 33px;
            font-weight: 900;
            background: linear-gradient(135deg, #0b74ff, #0642a0);
            box-shadow: 0 10px 24px rgba(11, 99, 229, .22);
        }

        .nav {
            display: flex;
            justify-content: center;
            align-items: center;
            gap: 46px;
            font-size: 20px;
            font-weight: 800;
        }

        .nav a {
            position: relative;
            padding: 31px 0 28px;
            color: #172742;
        }

        .nav a.active {
            color: var(--blue);
        }

        .nav a.active::after {
            content: "";
            position: absolute;
            right: 0;
            left: 0;
            bottom: 13px;
            height: 4px;
            border-radius: 999px;
            background: var(--blue);
        }

        .menu-toggle {
            display: none;
        }

        .menu-button {
            display: none;
            width: 44px;
            height: 44px;
            align-items: center;
            justify-content: center;
            flex-direction: column;
            gap: 5px;
            border: 1px solid #d7e1ed;
            border-radius: 12px;
            background: #fff;
            cursor: pointer;
            box-shadow: 0 8px 20px rgba(16, 34, 61, .08);
        }

        .menu-button span {
            width: 21px;
            height: 2px;
            border-radius: 99px;
            background: #10223d;
            transition: transform .2s ease, opacity .2s ease;
        }

        .search {
            width: 430px;
            height: 50px;
            display: flex;
            align-items: center;
            gap: 12px;
            padding: 0 18px;
            border: 1px solid #d7e1ed;
            border-radius: 15px;
            color: #7a8798;
            background: #fff;
            font-size: 18px;
            box-shadow: inset 0 2px 8px rgba(16, 34, 61, .04);
        }

        .search-icon {
            width: 22px;
            height: 22px;
            border: 3px solid #1f2937;
            border-radius: 50%;
            position: relative;
            transform: scale(.78);
        }

        .search-icon::after {
            content: "";
            position: absolute;
            width: 10px;
            height: 3px;
            background: #1f2937;
            bottom: -6px;
            left: -8px;
            transform: rotate(-45deg);
            border-radius: 9px;
        }

        .sun {
            width: 30px;
            height: 30px;
            display: grid;
            place-items: center;
            font-size: 28px;
            color: #172742;
        }

        .login {
            width: 106px;
            height: 50px;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 10px;
            color: #fff;
            background: linear-gradient(180deg, #0d71f4, #0754c4);
            border-radius: 11px;
            font-size: 19px;
            font-weight: 900;
            box-shadow: 0 9px 20px rgba(11, 99, 229, .22);
        }

        .login .user-icon {
            width: 17px;
            height: 17px;
            border: 2px solid #fff;
            border-radius: 50%;
            position: relative;
        }

        .login .user-icon::after {
            content: "";
            position: absolute;
            right: -6px;
            bottom: -11px;
            width: 27px;
            height: 15px;
            border: 2px solid #fff;
            border-top-left-radius: 18px;
            border-top-right-radius: 18px;
            border-bottom: 0;
        }

        .hero {
            height: 326px;
            margin-top: 20px;
            border-radius: 15px;
            overflow: hidden;
            position: relative;
            color: #fff;
            background:
                linear-gradient(90deg, rgba(3, 26, 54, .04), rgba(3, 26, 54, .14)),
                url("/images/home-hero-board.jpg") center / cover no-repeat,
                #0b3d5b;
            box-shadow: 0 10px 27px rgba(11, 53, 86, .18);
        }

        .hero.reference-hero {
            height: auto;
            aspect-ratio: 1436 / 286;
            background: url("/images/home-reference/hero.jpg") center / cover no-repeat;
        }

        .hero.reference-hero > * {
            display: none;
        }

        .hero .brush {
            position: absolute;
            left: 38px;
            top: 28px;
            width: 180px;
            height: 78px;
            background: linear-gradient(135deg, #0786d8, #006ab1);
            clip-path: polygon(4% 52%, 100% 0, 84% 23%, 99% 34%, 56% 54%, 85% 59%, 37% 74%, 67% 94%, 0 100%, 28% 71%);
            opacity: .9;
        }

        .chalk {
            position: absolute;
            inset: 0;
            opacity: .84;
            pointer-events: none;
            display: none;
        }

        .formula {
            position: absolute;
            color: rgba(255,255,255,.78);
            font-family: Georgia, "Times New Roman", serif;
            font-style: italic;
            text-shadow: 0 1px 0 rgba(0,0,0,.18);
        }

        .f1 { right: 52%; top: 58px; font-size: 31px; color: #f4bf45; }
        .f2 { right: 62%; top: 62px; font-size: 25px; }
        .f3 { right: 45%; top: 178px; font-size: 35px; }
        .f4 { left: 315px; top: 50px; font-size: 25px; }
        .f5 { left: 122px; top: 115px; width: 175px; height: 120px; border: 2px solid rgba(255,255,255,.22); border-right-color: transparent; border-bottom-color: transparent; transform: skew(-12deg); }
        .f5::before { content: ""; position: absolute; inset: 34px 20px auto auto; width: 120px; height: 44px; border-top: 2px solid rgba(255,255,255,.52); transform: rotate(31deg); }
        .f5::after { content: "△"; position: absolute; top: 28px; left: 34px; font-size: 78px; font-style: normal; color: rgba(255,255,255,.42); }

        .axis {
            position: absolute;
            right: 50%;
            bottom: 45px;
            width: 260px;
            height: 120px;
            opacity: .58;
        }

        .axis::before,
        .axis::after {
            content: "";
            position: absolute;
            background: rgba(255,255,255,.8);
            border-radius: 3px;
        }

        .axis::before { width: 230px; height: 2px; bottom: 38px; right: 8px; }
        .axis::after { width: 2px; height: 92px; bottom: 6px; right: 55px; }

        .curve {
            position: absolute;
            right: 70px;
            bottom: 50px;
            width: 138px;
            height: 70px;
            border-bottom: 3px solid rgba(255,255,255,.75);
            border-radius: 50%;
            transform: rotate(-4deg);
        }

        .hero-copy {
            position: absolute;
            z-index: 2;
            left: 245px;
            top: 36px;
            width: 520px;
            padding: 0;
            text-align: right;
        }

        .hero h1 {
            margin: 0;
            font-size: 58px;
            line-height: 1.18;
            font-weight: 950;
            text-shadow: 0 2px 0 rgba(0,0,0,.08);
        }

        .hero h1 span {
            display: block;
            color: var(--amber);
        }

        .hero p {
            margin: 16px 0 22px;
            color: rgba(255,255,255,.94);
            font-size: 19px;
            font-weight: 700;
            line-height: 1.9;
        }

        .cta {
            height: 47px;
            min-width: 178px;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            gap: 11px;
            border-radius: 9px;
            background: linear-gradient(180deg, #ffc22b, #f5a900);
            color: #16233d;
            font-size: 20px;
            font-weight: 950;
            box-shadow: 0 10px 20px rgba(248, 183, 25, .25);
        }

        .teacher-back {
            position: absolute;
            z-index: 2;
            left: 210px;
            bottom: 0;
            width: 250px;
            height: 290px;
            display: none;
        }

        .teacher-back .head {
            position: absolute;
            top: 16px;
            left: 92px;
            width: 67px;
            height: 82px;
            border-radius: 43% 46% 45% 42%;
            background: linear-gradient(100deg, #d49b79, #f2c19f);
        }

        .teacher-back .hair {
            position: absolute;
            top: 5px;
            left: 78px;
            width: 86px;
            height: 54px;
            border-radius: 54% 45% 42% 36%;
            background: #171923;
        }

        .teacher-back .body {
            position: absolute;
            left: 34px;
            bottom: 0;
            width: 155px;
            height: 205px;
            border-radius: 70px 55px 0 0;
            background: linear-gradient(115deg, #0d2d54, #1c5e91);
            box-shadow: inset -20px 0 36px rgba(255,255,255,.08);
        }

        .teacher-back .arm {
            position: absolute;
            left: 132px;
            top: 97px;
            width: 92px;
            height: 18px;
            border-radius: 20px;
            background: #e4b18e;
            transform: rotate(-37deg);
            transform-origin: right center;
        }

        .teacher-back .chalk-stick {
            position: absolute;
            left: 220px;
            top: 62px;
            width: 32px;
            height: 5px;
            border-radius: 8px;
            background: #fff;
            transform: rotate(-35deg);
        }

        .hero-arrow {
            position: absolute;
            z-index: 4;
            top: 50%;
            width: 47px;
            height: 47px;
            display: grid;
            place-items: center;
            border-radius: 50%;
            background: rgba(255,255,255,.94);
            color: #22334f;
            font-size: 33px;
            font-weight: 700;
            transform: translateY(-50%);
            box-shadow: 0 6px 20px rgba(8, 36, 66, .16);
        }

        .hero-arrow.r { right: 24px; }
        .hero-arrow.l { left: 24px; }

        .dots {
            position: absolute;
            z-index: 5;
            right: 46%;
            bottom: 20px;
            display: flex;
            gap: 10px;
        }

        .dot {
            width: 10px;
            height: 10px;
            border-radius: 99px;
            background: rgba(255,255,255,.62);
        }

        .dot.active {
            width: 28px;
            background: var(--amber);
        }

        .middle {
            display: grid;
            grid-template-columns: 598fr 824fr;
            gap: 14px;
            margin-top: 17px;
        }

        .reference-tile {
            display: block;
            overflow: hidden;
            border-radius: 14px;
            background: #fff;
            box-shadow: 0 8px 24px rgba(16, 34, 61, .08);
        }

        .reference-tile img {
            width: 100%;
            height: auto;
            display: block;
        }

        .ref-only {
            display: none;
        }

        .path-card {
            position: relative;
            min-height: 386px;
            overflow: hidden;
            border-radius: 14px;
            padding: 28px 32px;
            color: #fff;
            background:
                radial-gradient(circle at 72% 24%, rgba(255,255,255,.17), transparent 18%),
                linear-gradient(100deg, rgba(7,80,88,.95), rgba(16,103,111,.82)),
                #0c5963;
            box-shadow: 0 10px 28px rgba(13, 89, 100, .16);
        }

        .path-card::before {
            content: "";
            position: absolute;
            inset: 0;
            background:
                linear-gradient(90deg, transparent 0 49%, rgba(255,255,255,.18) 49% 50%, transparent 50%),
                linear-gradient(0deg, transparent 0 49%, rgba(255,255,255,.13) 49% 50%, transparent 50%);
            background-size: 74px 74px;
            opacity: .2;
        }

        .path-card .tag {
            position: relative;
            z-index: 2;
            display: inline-flex;
            padding: 7px 15px;
            border: 1px solid rgba(255,255,255,.75);
            border-radius: 9px;
            font-size: 17px;
            font-weight: 800;
        }

        .path-card h2 {
            position: relative;
            z-index: 2;
            margin: 29px 0 4px;
            font-size: 50px;
            line-height: 1.12;
            font-weight: 950;
        }

        .path-card h2 span {
            display: block;
            color: var(--amber);
        }

        .path-card p {
            position: relative;
            z-index: 2;
            margin: 0 0 18px;
            font-size: 19px;
            font-weight: 700;
        }

        .path-button {
            position: relative;
            z-index: 3;
            display: inline-flex;
            align-items: center;
            gap: 10px;
            height: 43px;
            padding: 0 18px;
            border: 1px solid rgba(255,255,255,.8);
            border-radius: 9px;
            font-size: 18px;
            font-weight: 850;
            background: rgba(6, 37, 55, .22);
        }

        .stairs {
            position: absolute;
            z-index: 2;
            left: 52px;
            bottom: 43px;
            width: 330px;
            height: 246px;
        }

        .stairs .pole {
            position: absolute;
            top: 2px;
            left: 62px;
            width: 5px;
            height: 108px;
            background: #ffbc1e;
        }

        .stairs .flag {
            position: absolute;
            top: 0;
            left: 64px;
            width: 0;
            height: 0;
            border-top: 27px solid transparent;
            border-bottom: 27px solid transparent;
            border-right: 64px solid #ffbc1e;
        }

        .stair {
            position: absolute;
            left: calc(var(--n) * 37px);
            bottom: calc(var(--n) * 31px);
            width: 228px;
            height: 39px;
            display: flex;
            align-items: center;
            justify-content: center;
            color: #1d2839;
            font-size: 15px;
            font-weight: 900;
            border: 1px solid rgba(0,0,0,.1);
            background: linear-gradient(180deg, #f6f6f2, #cdd2d5);
            box-shadow: 0 10px 20px rgba(0,0,0,.18);
            transform: skewY(-5deg);
        }

        .panel {
            min-height: 386px;
            padding: 8px 18px 18px;
            border: 1px solid var(--line);
            border-radius: 14px;
            background: #fff;
            box-shadow: 0 8px 24px rgba(16, 34, 61, .08);
        }

        .panel-head {
            height: 48px;
            display: flex;
            align-items: end;
            justify-content: space-between;
        }

        .panel-head h2 {
            margin: 0;
            font-size: 26px;
            font-weight: 950;
        }

        .panel-head small {
            color: var(--muted);
            font-size: 15px;
        }

        .video-row {
            display: grid;
            grid-template-columns: repeat(4, minmax(0, 1fr));
            gap: 18px;
            margin-top: 12px;
        }

        .video h3 {
            margin: 10px 0 2px;
            text-align: center;
            font-size: 19px;
            font-weight: 950;
        }

        .video p {
            margin: 0;
            text-align: center;
            color: var(--muted);
            font-size: 15px;
        }

        .thumb {
            position: relative;
            height: 122px;
            overflow: hidden;
            border-radius: 9px;
            background: #102038;
            box-shadow: inset 0 0 0 1px rgba(255,255,255,.08);
        }

        .thumb img {
            width: 100%;
            height: 100%;
            display: block;
            object-fit: cover;
        }

        .categories-block {
            margin-top: 22px;
            padding: 18px 0 0;
            border-top: 1px solid #eef3f8;
        }

        .categories-title {
            display: flex;
            align-items: center;
            justify-content: flex-start;
            gap: 10px;
            margin-bottom: 14px;
            font-size: 24px;
            font-weight: 950;
        }

        .cat-grid {
            display: grid;
            grid-template-columns: repeat(5, 1fr);
            gap: 16px;
        }

        .cat {
            display: grid;
            justify-items: center;
            gap: 8px;
            font-size: 18px;
            font-weight: 850;
        }

        .cat-icon {
            width: 72px;
            height: 72px;
            display: grid;
            place-items: center;
            border-radius: 50%;
        }

        .cat-icon img {
            width: 72px;
            height: 72px;
            display: block;
        }

        .bottom {
            display: grid;
            grid-template-columns: 450fr 968fr;
            gap: 18px;
            margin-top: 26px;
        }

        .quick {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 12px;
        }

        .quick-card {
            min-height: 220px;
            display: flex;
            flex-direction: column;
            justify-content: space-between;
            align-items: center;
            text-align: center;
            padding: 23px 16px 20px;
            border: 1px solid var(--line);
            border-radius: 12px;
            background: #fff;
            box-shadow: 0 8px 22px rgba(16, 34, 61, .06);
        }

        a.quick-card {
            color: inherit;
        }

        .quick-icon {
            width: 54px;
            height: 54px;
            display: grid;
            place-items: center;
            border-radius: 12px;
            color: #fff;
            font-weight: 950;
            font-size: 24px;
        }

        .quick-icon img {
            width: 54px;
            height: 54px;
            display: block;
        }

        .quick-card h3 {
            margin: 4px 0 0;
            font-size: 21px;
            font-weight: 950;
        }

        .quick-card p {
            margin: 8px 0;
            color: var(--muted);
            font-size: 15px;
            line-height: 1.8;
        }

        .quick-btn {
            height: 39px;
            min-width: 122px;
            display: inline-flex;
            align-items: center;
            justify-content: center;
            border-radius: 8px;
            color: #fff;
            font-size: 16px;
            font-weight: 850;
            background: var(--green);
        }

        .quick-card:nth-child(2) .quick-icon,
        .quick-card:nth-child(2) .quick-btn { background: #f97316; }
        .quick-card:nth-child(3) .quick-icon,
        .quick-card:nth-child(3) .quick-btn { background: var(--blue); }

        .courses {
            padding: 10px 12px 12px;
            border: 1px solid var(--line);
            border-radius: 14px;
            background: #fff;
            box-shadow: 0 8px 24px rgba(16, 34, 61, .08);
        }

        .courses-head {
            height: 36px;
            display: flex;
            align-items: center;
            justify-content: space-between;
            font-size: 22px;
            font-weight: 950;
        }

        .course-row {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 14px;
        }

        .course {
            position: relative;
            height: 200px;
            overflow: hidden;
            display: block;
            border-radius: 12px;
            color: #fff;
            background:
                linear-gradient(135deg, rgba(255,255,255,.06), rgba(255,255,255,0) 45%),
                linear-gradient(135deg, #0b63ce, #082f69);
        }

        .course.green {
            background:
                linear-gradient(135deg, rgba(255,255,255,.06), rgba(255,255,255,0) 45%),
                linear-gradient(135deg, #159565, #09573d);
        }

        .course.orange {
            background:
                linear-gradient(135deg, rgba(255,255,255,.06), rgba(255,255,255,0) 45%),
                linear-gradient(135deg, #f06423, #be310d);
        }

        .course::after {
            content: "";
            position: absolute;
            inset: 0;
            background:
                linear-gradient(90deg, transparent 0 47%, rgba(255,255,255,.13) 48%, transparent 49%),
                linear-gradient(0deg, transparent 0 48%, rgba(255,255,255,.1) 49%, transparent 50%);
            background-size: 68px 68px;
            opacity: .18;
        }

        .course-badge {
            position: absolute;
            z-index: 3;
            top: 10px;
            left: 10px;
            padding: 5px 10px;
            border-radius: 8px;
            background: #ef4444;
            color: #fff;
            font-size: 13px;
            font-weight: 900;
        }

        .course-badge.blue { background: #0b8bff; }
        .course-badge.green { background: #22c55e; }

        .course-person {
            position: absolute;
            z-index: 2;
            right: 0;
            bottom: 42px;
            width: 142px;
            height: 150px;
            object-fit: cover;
            object-position: bottom right;
        }

        .course-copy {
            position: relative;
            z-index: 3;
            margin: 28px 136px 0 18px;
            text-align: right;
        }

        .course h3 {
            margin: 0;
            font-size: 34px;
            line-height: 1.05;
            font-weight: 950;
        }

        .course p {
            margin: 7px 0 0;
            font-size: 17px;
            font-weight: 850;
            color: rgba(255,255,255,.94);
        }

        .course small {
            display: block;
            margin-top: 16px;
            font-size: 13px;
            font-weight: 800;
            color: rgba(255,255,255,.82);
        }

        .course-formula {
            position: absolute;
            z-index: 2;
            left: 20px;
            top: 92px;
            color: rgba(255,255,255,.82);
            font-family: Georgia, "Times New Roman", serif;
            font-size: 23px;
            font-style: italic;
        }

        .course-line {
            position: absolute;
            z-index: 2;
            left: 38px;
            top: 86px;
            width: 96px;
            height: 74px;
            border-right: 2px solid rgba(255,255,255,.42);
            border-bottom: 2px solid rgba(255,255,255,.42);
            transform: skew(-8deg);
        }

        .course-footer {
            position: absolute;
            z-index: 4;
            right: 0;
            left: 0;
            bottom: 0;
            height: 43px;
            display: grid;
            grid-template-columns: 1.35fr .95fr .95fr;
            align-items: center;
            padding: 0 12px;
            background: linear-gradient(180deg, #ffd95e, #ffc333);
            color: #1a2a40;
            font-size: 14px;
            font-weight: 950;
        }

        .quick.compact {
            align-self: stretch;
        }

        .quick.compact .quick-card {
            min-height: 218px;
        }

        @media (max-width: 1480px) {
            .topbar { gap: 20px; padding: 0 32px; }
            .nav { gap: 30px; }
            .search { width: 360px; }
            .shell { padding: 0 34px 34px; }
            .hero-copy { left: 170px; }
            .video-row { gap: 14px; }
        }

        @media (max-width: 1320px) {
            .topbar {
                display: flex;
                flex-wrap: wrap;
                justify-content: center;
                align-items: center;
                gap: 16px 26px;
                padding: 14px 24px 12px;
                height: auto;
            }
            .brand { order: 1; }
            .search { order: 2; width: 360px; max-width: calc(100vw - 48px); }
            .sun { order: 2; }
            .login { order: 2; }
            .nav {
                order: 3;
                flex: 1 1 100%;
                gap: 34px;
                justify-content: center;
                overflow: visible;
            }
            .nav a { padding: 14px 0 18px; }
            .nav a.active::after { bottom: 3px; }
            .shell { padding: 0 22px 28px; }
            .hero-copy { left: auto; right: 44px; width: min(520px, calc(100% - 88px)); padding: 0; }
            .teacher-back { left: 80px; }
            .middle, .bottom { grid-template-columns: 1fr; }
        }

        @media (max-width: 760px) {
            .topbar {
                display: grid;
                grid-template-columns: 82px 1fr 44px;
                grid-template-areas:
                    "login brand menu"
                    "search search search"
                    "nav nav nav";
                gap: 12px;
                padding: 12px 16px;
                position: sticky;
                top: 0;
                z-index: 30;
                direction: ltr;
            }

            .brand {
                order: 1;
                grid-area: brand;
                font-size: 24px;
                justify-self: end;
                direction: rtl;
            }

            .brand-mark {
                width: 46px;
                height: 46px;
                border-radius: 14px;
                font-size: 28px;
            }

            .login {
                order: 1;
                grid-area: login;
                width: 82px;
                height: 44px;
                font-size: 16px;
                justify-self: start;
                direction: rtl;
            }

            .login .user-icon { display: none; }

            .menu-button {
                display: inline-flex;
                order: 1;
                grid-area: menu;
                justify-self: end;
            }

            .menu-toggle:checked + .menu-button span:nth-child(1) {
                transform: translateY(7px) rotate(45deg);
            }

            .menu-toggle:checked + .menu-button span:nth-child(2) {
                opacity: 0;
            }

            .menu-toggle:checked + .menu-button span:nth-child(3) {
                transform: translateY(-7px) rotate(-45deg);
            }

            .search {
                order: 2;
                grid-area: search;
                width: 100%;
                height: 46px;
                font-size: 17px;
                direction: rtl;
            }

            .sun { display: none; }

            .nav {
                order: 3;
                grid-area: nav;
                display: none;
                grid-template-columns: repeat(2, minmax(0, 1fr));
                gap: 10px;
                padding: 0;
                direction: rtl;
            }

            .menu-toggle:checked + .menu-button + .nav {
                display: grid;
                padding-top: 4px;
            }

            .nav a {
                display: flex;
                align-items: center;
                justify-content: center;
                min-height: 42px;
                padding: 8px 12px;
                border: 1px solid #dce6f1;
                border-radius: 12px;
                background: #fff;
                font-size: 17px;
                box-shadow: 0 6px 16px rgba(16, 34, 61, .05);
            }

            .nav a.active {
                color: #fff;
                border-color: #0b63e5;
                background: #0b63e5;
            }

            .nav a.active::after { display: none; }

            .shell { padding: 0 14px 24px; }

            .hero.reference-hero {
                min-height: 360px;
                aspect-ratio: auto;
                background:
                    linear-gradient(180deg, rgba(4, 30, 59, .2), rgba(4, 30, 59, .4)),
                    url("/images/home-hero-board.jpg") center / cover no-repeat;
            }

            .hero.reference-hero > * { display: initial; }

            .hero.reference-hero .chalk,
            .hero.reference-hero .teacher-back { display: none; }

            .hero-arrow {
                width: 38px;
                height: 38px;
                font-size: 26px;
            }

            .hero-arrow.r { right: 12px; }
            .hero-arrow.l { left: 12px; }

            .brush {
                left: 16px;
                top: 18px;
                width: 125px;
                height: 54px;
            }

            .hero-copy {
                position: absolute;
                right: 26px;
                left: 26px;
                top: 62px;
                width: auto;
                padding: 0;
            }

            .hero h1 {
                font-size: 43px;
                line-height: 1.2;
            }

            .hero p {
                max-width: 310px;
                margin-top: 14px;
                font-size: 17px;
                line-height: 1.8;
            }

            .cta {
                height: 44px;
                min-width: 158px;
                font-size: 18px;
            }

            .dots {
                right: 50%;
                transform: translateX(50%);
                bottom: 15px;
            }

            .middle,
            .bottom,
            .course-row {
                grid-template-columns: 1fr;
            }

            .video-row {
                grid-template-columns: repeat(2, minmax(0, 1fr));
                gap: 12px;
            }

            .middle { gap: 14px; margin-top: 14px; }

            .path-card {
                min-height: 410px;
                padding: 22px;
            }

            .path-card h2 { font-size: 40px; }
            .path-card p { font-size: 17px; }

            .stairs {
                left: 50%;
                bottom: 26px;
                width: 270px;
                height: 210px;
                transform: translateX(-50%) scale(.82);
                transform-origin: bottom center;
            }

            .panel {
                min-height: 0;
                padding: 12px;
            }

            .panel-head {
                height: auto;
                align-items: center;
                margin-bottom: 12px;
            }

            .panel-head h2,
            .categories-title,
            .courses-head {
                font-size: 22px;
            }

            .thumb { height: 106px; }

            .video h3 {
                margin-top: 8px;
                font-size: 17px;
                line-height: 1.25;
            }

            .video p {
                font-size: 14px;
                line-height: 1.35;
            }

            .cat-grid {
                grid-template-columns: repeat(5, minmax(0, 1fr));
                gap: 8px;
            }

            .cat {
                gap: 6px;
                font-size: 14px;
                line-height: 1.25;
            }

            .cat:last-child { grid-column: auto; }

            .cat-icon,
            .cat-icon img {
                width: 54px;
                height: 54px;
            }

            .bottom { margin-top: 14px; }

            .quick {
                grid-template-columns: repeat(3, minmax(0, 1fr));
                gap: 8px;
            }

            .quick-card {
                min-height: 142px;
                padding: 12px 8px;
            }

            .quick.compact .quick-card { min-height: 142px; }

            .quick-icon,
            .quick-icon img {
                width: 42px;
                height: 42px;
            }

            .quick-card h3 {
                font-size: 16px;
                line-height: 1.2;
            }

            .quick-card p {
                margin: 4px 0;
                font-size: 12px;
                line-height: 1.45;
            }

            .quick-btn {
                min-width: 0;
                width: 100%;
                height: 32px;
                padding: 0 6px;
                font-size: 12px;
            }

            .courses {
                padding: 12px;
            }

            .courses-head {
                height: auto;
                margin-bottom: 12px;
            }

            .course {
                height: 190px;
            }

            .course-person {
                width: 116px;
                height: 136px;
                right: 0;
            }

            .course-copy {
                margin: 26px 110px 0 14px;
            }

            .course h3 {
                font-size: 29px;
            }

            .course p {
                font-size: 16px;
            }

            .course small {
                margin-top: 11px;
                font-size: 12px;
            }

            .course-formula {
                left: 14px;
                top: 88px;
                font-size: 20px;
            }

            .course-footer {
                grid-template-columns: 1.2fr .9fr .9fr;
                font-size: 13px;
            }
        }

        @media (max-width: 420px) {
            .topbar {
                grid-template-columns: 72px 1fr 40px;
                gap: 10px;
                padding: 10px 12px;
            }

            .brand {
                font-size: 21px;
                gap: 8px;
            }

            .brand-mark {
                width: 40px;
                height: 40px;
                font-size: 25px;
            }

            .login {
                width: 72px;
                height: 40px;
                font-size: 15px;
            }

            .menu-button {
                width: 40px;
                height: 40px;
                border-radius: 11px;
            }

            .search {
                height: 43px;
                font-size: 15px;
                padding: 0 13px;
            }

            .nav {
                grid-template-columns: 1fr 1fr;
                gap: 8px;
            }

            .nav a {
                min-height: 40px;
                font-size: 16px;
            }

            .hero.reference-hero { min-height: 340px; }
            .hero-copy { right: 20px; left: 20px; top: 58px; }
            .hero h1 { font-size: 37px; }
            .hero p { font-size: 16px; }
            .path-card h2 { font-size: 35px; }
            .stairs { transform: translateX(-50%) scale(.72); }
            .thumb { height: 96px; }
            .cat-grid {
                grid-template-columns: repeat(5, 64px);
                justify-content: space-between;
                overflow-x: auto;
                padding-bottom: 2px;
                scrollbar-width: none;
            }

            .cat-grid::-webkit-scrollbar { display: none; }

            .cat {
                font-size: 13px;
            }

            .cat-icon,
            .cat-icon img {
                width: 50px;
                height: 50px;
            }
            .course h3 { font-size: 25px; }
            .course-copy { margin-right: 96px; }
            .course-person { width: 98px; }
            .course-footer { font-size: 12px; padding: 0 8px; }
        }