.topbar {
    height: 64px;
    padding: 0 48px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    background: rgba(255, 255, 255, 0.78);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid rgba(0, 0, 0, 0.06);
    position: sticky;
    top: 0;
    z-index: 10;
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
    font-size: 18px;
    color: #1d1d1f;
    text-decoration: none;
}

.brand-logo {
    width: 36px;
    height: 36px;
}

.brand .brand-wordmark {
    font-size: 23px;
    font-weight: 900;
}

.topbar-actions a {
    color: #0071e3;
    font-size: 14px;
}

.topbar-profile-btn {
    min-height: 40px;
    padding: 0;
    border: 0;
    background: transparent;
    color: #0071e3;
    cursor: pointer;
    font: inherit;
    font-size: 14px;
    font-weight: 700;
}

.hero {
    text-align: center;
    padding: 90px 24px 50px;
}

.badge {
    display: inline-block;
    padding: 8px 16px;
    border-radius: 999px;
    background: #e8f0ff;
    color: #0066cc;
    font-size: 14px;
    margin-bottom: 22px;
}

h1 {
    font-size: 68px;
    line-height: 1.05;
    letter-spacing: -0.06em;
    margin-bottom: 22px;
}

.subtitle {
    max-width: 760px;
    margin: 0 auto;
    color: #6e6e73;
    font-size: 21px;
    line-height: 1.7;
}

.stage-info {
    max-width: 1080px;
    margin: 30px auto 36px;
    padding: 32px;
    background: white;
    border-radius: 30px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.06);
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
}

.info-item {
    background: #f5f5f7;
    border-radius: 22px;
    padding: 22px;
}

.info-item strong {
    display: block;
    font-size: 22px;
    margin-bottom: 8px;
}

.info-item span {
    color: #6e6e73;
    font-size: 14px;
    line-height: 1.6;
}

.lesson-section {
    max-width: 1080px;
    margin: 0 auto 90px;
    padding: 0 24px;
}

.section-title {
    display: flex;
    align-items: end;
    justify-content: space-between;
    margin-bottom: 22px;
}

.section-title h2 {
    font-size: 34px;
    letter-spacing: -0.04em;
}

.section-title p {
    color: #86868b;
    font-size: 15px;
}

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

.lesson-card {
    background: white;
    border-radius: 28px;
    padding: 26px;
    min-height: 230px;
    box-shadow: 0 14px 45px rgba(0, 0, 0, 0.06);
    transition: 0.25s;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
}

.lesson-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 28px 70px rgba(0, 0, 0, 0.1);
}

.lesson-card.is-checking-access {
    pointer-events: none;
    opacity: 0.72;
}

.lesson-num {
    color: #0071e3;
    font-size: 14px;
    font-weight: 700;
    margin-bottom: 12px;
}

.lesson-card h3 {
    font-size: 24px;
    letter-spacing: -0.03em;
    margin-bottom: 10px;
}

.lesson-desc {
    color: #6e6e73;
    line-height: 1.7;
    font-size: 15px;
    margin-bottom: 18px;
}

.tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 20px;
}

.lesson-progress {
    margin-top: 6px;
}

.lesson-progress-label {
    margin-bottom: 8px;
    color: #6e6e73;
    font-size: 12px;
    font-weight: 700;
}

.lesson-progress-track {
    width: 100%;
    height: 8px;
    border-radius: 999px;
    background: #e5ecf5;
    overflow: hidden;
}

.lesson-progress-track span {
    display: block;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, #0a84ff, #34c759);
}

.tag {
    padding: 6px 10px;
    border-radius: 999px;
    background: #f5f5f7;
    color: #555;
    font-size: 12px;
}

.start {
    color: #0071e3;
    font-weight: 700;
    font-size: 15px;
}

.locked {
    opacity: 0.55;
}

.locked .start {
    color: #86868b;
}

.bottom-nav {
    max-width: 1080px;
    margin: 0 auto 60px;
    padding: 0 24px;
    display: flex;
    gap: 16px;
}

.bottom-nav a {
    flex: 1;
    text-align: center;
    padding: 22px;
    border-radius: 24px;
    background: white;
    color: #0071e3;
    font-weight: 700;
    box-shadow: 0 14px 40px rgba(0, 0, 0, 0.06);
}

@media (max-width: 900px) {
    .topbar {
        padding: 0 20px;
    }

    h1 {
        font-size: 44px;
    }

    .subtitle {
        font-size: 18px;
    }

    .stage-info {
        grid-template-columns: 1fr;
        margin: 20px 24px 34px;
    }

    .lesson-grid {
        grid-template-columns: 1fr;
    }

    .section-title {
        display: block;
    }

    .section-title p {
        margin-top: 8px;
    }

    .bottom-nav {
        flex-direction: column;
    }
}

@media (max-width: 700px) {
    .topbar {
        height: auto;
        padding: 14px 20px;
        flex-direction: column;
        align-items: flex-start;
        gap: 12px;
    }

    .brand {
        font-size: 16px;
        line-height: 1.25;
    }

    .brand-logo {
        width: 32px;
        height: 32px;
    }

    .brand .brand-wordmark {
        font-size: 20px;
    }

    .topbar .topbar-actions {
        width: 100%;
        display: flex;
        justify-content: space-between;
        align-items: center;
        flex-wrap: nowrap;
        gap: 12px;
    }

    .topbar .topbar-actions > a {
        min-height: 40px;
        padding: 0 14px;
        border-radius: 14px;
        display: inline-flex;
        align-items: center;
        background: rgba(255, 255, 255, 0.92);
        color: #1d1d1f;
        font-size: 13px;
        font-weight: 700;
        white-space: nowrap;
        box-shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
    }

    .topbar .topbar-actions .topbar-profile-btn {
        min-height: 40px;
        padding: 0 14px;
        border-radius: 14px;
        background: rgba(255, 255, 255, 0.92);
        color: #1d1d1f;
        font-size: 13px;
        box-shadow: 0 8px 24px rgba(15, 23, 42, 0.08);
        white-space: nowrap;
    }

    .topbar .topbar-actions .auth-status {
        width: auto;
        min-width: 0;
        justify-content: flex-end;
        flex: 0 1 auto;
    }

    .topbar .topbar-actions .auth-account {
        width: auto;
        gap: 8px;
    }

    .topbar .topbar-actions .auth-feedback-btn {
        min-height: 40px;
        padding: 0 12px;
        font-size: 13px;
    }
}

@media (max-width: 520px) {
    .topbar .topbar-actions {
        align-items: flex-start;
    }

    .topbar .topbar-actions .auth-status {
        flex: 1;
    }

    .topbar .topbar-actions .auth-account {
        justify-content: flex-end;
    }
}