:root {
    --color-background: #f6f4ef;
    --color-header: #ffffff;
    --color-surface: #ffffff;
    --color-panel: #fbfaf7;
    --color-primary: #06345f;
    --color-primary-dark: #052b4f;
    --color-text: #111827;
    --color-muted: #4b5563;
    --color-border: #d4c8b8;
    --color-border-cool: #cbd5e1;
    --color-success: #3f6f39;
    --color-warning: #8b5d18;
    --color-error: #8c2d22;
    --color-info: #3f5368;
    --color-success-muted: #e9ead7;
    --color-error-muted: #ead5cf;
    --content-width: 1180px;
}

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

body {
    min-height: 100vh;
    background: var(--color-background);
    color: var(--color-text);
    font-family: "Source Sans 3", "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.7;
    letter-spacing: 0;
}

.container {
    width: 100%;
}

.hero-header {
    background: var(--color-header);
    border-bottom: 1px solid var(--color-border-cool);
    padding: 68px max(32px, calc((100vw - var(--content-width)) / 2)) 82px;
    position: relative;
}

.header-logo {
    display: none;
}

.notebook-mark {
    height: 50px;
    margin: 0 0 24px;
    position: relative;
    width: 74px;
}

.notebook-mark span {
    border: 5px solid #111111;
    border-bottom: 0;
    border-radius: 999px 999px 0 0;
    bottom: 0;
    display: block;
    position: absolute;
}

.notebook-mark span:nth-child(1) {
    height: 48px;
    left: 0;
    width: 72px;
}

.notebook-mark span:nth-child(2) {
    height: 36px;
    left: 9px;
    width: 54px;
}

.notebook-mark span:nth-child(3) {
    height: 24px;
    left: 18px;
    width: 36px;
}

.notebook-mark-small {
    height: 34px;
    margin: 0 auto 20px;
    width: 50px;
}

.notebook-mark-small span {
    border-width: 3px;
}

.notebook-mark-small span:nth-child(1) {
    height: 32px;
    width: 48px;
}

.notebook-mark-small span:nth-child(2) {
    height: 24px;
    left: 6px;
    width: 36px;
}

.notebook-mark-small span:nth-child(3) {
    height: 16px;
    left: 12px;
    width: 24px;
}

.hero-header h1 {
    color: var(--color-primary);
    font-size: clamp(3.4rem, 7vw, 5.6rem);
    font-weight: 900;
    line-height: 0.98;
    margin-bottom: 26px;
    max-width: 980px;
}

.hero-header p {
    color: var(--color-muted);
    font-size: clamp(1.25rem, 2.3vw, 2rem);
    font-weight: 500;
    line-height: 1.35;
    max-width: 940px;
}

.progress-top,
.hero-quote,
.nav-dots,
.section {
    max-width: var(--content-width);
    margin-left: auto;
    margin-right: auto;
}

.progress-top {
    background: transparent;
    border: 0;
    border-radius: 0;
    padding: 58px 32px 0;
}

.progress-top-bar {
    background: #d8e0e8;
    height: 12px;
    overflow: hidden;
}

.progress-top-fill {
    background: var(--color-primary);
    height: 100%;
    width: 0%;
    transition: width 0.35s ease;
}

.progress-top-text {
    display: flex;
    justify-content: space-between;
    align-items: baseline;
    gap: 16px;
    margin-top: 20px;
    color: var(--color-muted);
    font-size: clamp(1.05rem, 1.8vw, 1.42rem);
    font-weight: 900;
    letter-spacing: 0.04em;
    text-transform: uppercase;
}

#progressPercent {
    color: var(--color-primary);
}

.nav-dots {
    display: flex;
    flex-wrap: wrap;
    gap: 14px;
    padding: 28px 32px 0;
}

.nav-dot {
    min-width: 104px;
    min-height: 52px;
    padding: 10px 22px;
    border-radius: 8px;
    border: 2px solid var(--color-border);
    background: var(--color-panel);
    color: var(--color-muted);
    cursor: pointer;
    font: inherit;
    font-size: clamp(0.98rem, 1.5vw, 1.28rem);
    font-weight: 900;
    letter-spacing: 0.04em;
    text-transform: uppercase;
    transition: background 0.18s ease, border-color 0.18s ease, color 0.18s ease;
}

.nav-dot:hover,
.nav-dot:focus-visible {
    border-color: var(--color-primary);
    color: var(--color-primary);
    outline: none;
}

.nav-dot.active {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: #ffffff;
}

.nav-dot.completed:not(.active) {
    color: var(--color-primary);
}

.hero-quote {
    background: transparent;
    color: var(--color-text);
    padding: 40px 32px 56px;
    border-radius: 0;
    box-shadow: none;
    text-align: left;
}

.hero-quote p {
    border-left: 7px solid var(--color-primary);
    color: var(--color-text);
    font-size: clamp(1.25rem, 2vw, 1.68rem);
    font-weight: 900;
    line-height: 1.32;
    margin: 0;
    padding-left: 28px;
}

.section {
    display: none;
    background: transparent;
    border: 0;
    border-radius: 0;
    padding: 0 32px 82px;
    animation: slideIn 0.28s ease;
}

@keyframes slideIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.section.active {
    display: block;
}

.section h2 {
    color: var(--color-primary);
    font-size: clamp(2.7rem, 5vw, 4.2rem);
    font-weight: 900;
    line-height: 1.02;
    margin: 0 0 34px;
}

.section h2::before {
    background: #111111;
    content: "";
    display: block;
    height: 6px;
    margin: 0 0 24px;
    width: 54px;
}

.section h3 {
    color: var(--color-text);
    font-size: clamp(1.8rem, 3vw, 2.45rem);
    font-weight: 900;
    line-height: 1.12;
    margin: 58px 0 20px;
}

.section h4 {
    color: var(--color-text);
    font-size: 1.32rem;
    font-weight: 900;
    margin: 28px 0 12px;
}

p {
    font-size: clamp(1.08rem, 1.8vw, 1.42rem);
    line-height: 1.62;
    margin-bottom: 20px;
}

a {
    color: var(--color-primary);
    font-weight: 800;
}

.chapter-list {
    margin: 18px 0 26px 28px;
    padding-left: 14px;
}

.chapter-list li {
    font-size: clamp(1.04rem, 1.6vw, 1.26rem);
    line-height: 1.55;
    margin-bottom: 12px;
}

.learning-cards,
.feature-grid,
.prompt-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 18px;
    margin: 34px 0;
}

.learning-card,
.feature-card,
.prompt-card,
.tip-box,
.info-box,
.warning-box,
.danger-box,
.chapter-summary,
.scenario,
.accordion-item,
.completion {
    background: var(--color-surface);
    border: 2px solid var(--color-border);
    border-radius: 8px;
}

.learning-card,
.feature-card,
.prompt-card {
    padding: 24px;
}

.learning-card span,
.feature-card span,
.prompt-card span {
    display: block;
    color: var(--color-primary);
    font-size: 1.18rem;
    font-weight: 900;
    line-height: 1.2;
    margin-bottom: 8px;
}

.learning-card p,
.feature-card p,
.prompt-card p {
    color: var(--color-muted);
    font-size: 1.02rem;
    line-height: 1.45;
    margin: 0;
}

.tip-box,
.info-box,
.warning-box,
.danger-box,
.chapter-summary,
.scenario {
    border-left: 8px solid var(--color-primary);
    padding: 24px 28px;
    margin: 30px 0;
}

.info-box {
    border-left-color: var(--color-info);
}

.warning-box {
    border-left-color: var(--color-warning);
}

.danger-box {
    border-left-color: var(--color-error);
}

.tip-box strong,
.chapter-summary strong,
.scenario-header {
    color: var(--color-primary);
}

.info-box strong {
    color: var(--color-info);
}

.warning-box strong {
    color: var(--color-warning);
}

.danger-box strong {
    color: var(--color-error);
}

.scenario-header {
    font-size: 1.2rem;
    font-weight: 900;
    margin-bottom: 12px;
}

.lesson-banner {
    background: var(--color-primary);
    border-radius: 8px;
    color: #ffffff;
    margin: 36px 0;
    padding: 28px 32px;
}

.lesson-banner p {
    margin: 0;
}

.accordion {
    margin: 34px 0;
}

.accordion-item {
    overflow: hidden;
    margin-bottom: 14px;
}

.accordion-header {
    align-items: center;
    color: var(--color-primary);
    cursor: pointer;
    display: flex;
    font-size: 1.18rem;
    font-weight: 900;
    gap: 18px;
    justify-content: space-between;
    padding: 20px 24px;
}

.accordion-header:hover,
.accordion-header:focus-visible {
    background: #f1eee8;
    outline: none;
}

.accordion-arrow {
    transition: transform 0.2s ease;
}

.accordion-item.open .accordion-arrow {
    transform: rotate(180deg);
}

.accordion-content {
    display: none;
    border-top: 2px solid var(--color-border);
}

.accordion-item.open .accordion-content {
    display: block;
}

.accordion-body {
    padding: 24px;
}

.accordion-body p {
    font-size: 1.12rem;
}

.btn-nav {
    border-top: 2px solid var(--color-border);
    display: flex;
    gap: 16px;
    justify-content: space-between;
    margin-top: 42px;
    padding-top: 28px;
}

.btn {
    background: var(--color-primary);
    border: 2px solid var(--color-primary);
    border-radius: 8px;
    color: #ffffff;
    cursor: pointer;
    display: inline-block;
    font: inherit;
    font-size: 1.05rem;
    font-weight: 900;
    letter-spacing: 0.03em;
    padding: 13px 24px;
    text-decoration: none;
    text-transform: uppercase;
    transition: background 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.btn:hover,
.btn:focus-visible {
    background: var(--color-primary-dark);
    border-color: var(--color-primary-dark);
    outline: none;
    transform: translateY(-1px);
}

.btn-outline {
    background: transparent;
    color: var(--color-primary);
}

.btn-outline:hover,
.btn-outline:focus-visible {
    background: var(--color-primary);
    border-color: var(--color-primary);
    color: #ffffff;
}

.completion {
    padding: 34px;
    text-align: center;
}

.source-list {
    margin: 18px 0 0 28px;
}

.source-list li {
    font-size: 1.08rem;
    margin: 8px 0;
}

.toast {
    background: var(--color-primary);
    border-radius: 8px;
    bottom: 24px;
    color: #ffffff;
    font-weight: 800;
    left: 50%;
    padding: 12px 18px;
    position: fixed;
    transform: translateX(-50%);
    z-index: 20;
}

.toast[hidden] {
    display: none;
}

@media (max-width: 820px) {
    .hero-header {
        padding: 44px 22px 58px;
    }

    .progress-top,
    .nav-dots,
    .hero-quote,
    .section {
        padding-left: 22px;
        padding-right: 22px;
    }

    .progress-top {
        padding-top: 38px;
    }

    .nav-dots {
        gap: 10px;
    }

    .nav-dot {
        min-height: 46px;
        min-width: 0;
        padding: 9px 14px;
    }

    .learning-cards,
    .feature-grid,
    .prompt-grid {
        grid-template-columns: 1fr;
    }

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

    .btn-nav .btn {
        text-align: center;
        width: 100%;
    }
}
 .hidden { display: none !important; }
.gate-home-link { margin-top: 22px; color: inherit; font-weight: 750; text-underline-offset: 4px; }