* {
    box-sizing: border-box;
}

:root {
    --green-900: #12372a;
    --green-800: #174b38;
    --green-700: #1d6549;
    --green-100: #e8f3ed;

    --bg: #f5f7f6;
    --white: #ffffff;

    --text: #1b2420;
    --muted: #68736e;

    --border: #dde4e0;

    --correct: #15803d;
    --incorrect: #b91c1c;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    font-family:
        -apple-system,
        BlinkMacSystemFont,
        "Segoe UI",
        "Noto Sans JP",
        sans-serif;

    background: var(--bg);
    color: var(--text);
}

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

.container {
    width: min(1120px, 92%);
    margin: 0 auto;
}


/* HEADER */

.site-header {
    position: sticky;
    top: 0;
    z-index: 100;

    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(14px);

    border-bottom: 1px solid var(--border);
}

.header-inner {
    min-height: 72px;

    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    font-size: 22px;
    font-weight: 800;
    color: var(--green-900);
}

.subtitle {
    margin-top: 2px;
    font-size: 12px;
    color: var(--muted);
}

.header-button {
    padding: 9px 16px;
    background: var(--green-900);
    color: white;
    border-radius: 9px;
    font-size: 14px;
    font-weight: 700;
}


/* HERO */

.hero {
    padding: 95px 0 85px;
    background:
        radial-gradient(
            circle at 80% 20%,
            rgba(46, 125, 89, 0.15),
            transparent 35%
        );
}

.hero-inner {
    display: grid;
    grid-template-columns: 1.45fr 0.75fr;
    gap: 70px;
    align-items: center;
}

.hero-content {
    max-width: 720px;
}

.badge {
    display: inline-block;

    padding: 7px 13px;

    border-radius: 999px;

    background: var(--green-100);
    color: var(--green-700);

    font-size: 13px;
    font-weight: 700;
}

.hero h1 {
    margin: 24px 0 20px;

    font-size: clamp(44px, 6vw, 72px);
    line-height: 1.13;

    letter-spacing: -0.045em;
}

.hero p {
    max-width: 650px;
    margin-bottom: 34px;

    font-size: 18px;
    line-height: 1.9;

    color: var(--muted);
}

.hero-actions {
    display: flex;
    gap: 12px;
    flex-wrap: wrap;
}

.primary-button,
.secondary-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;

    min-height: 48px;
    padding: 0 22px;

    border-radius: 10px;
    font-weight: 700;
}

.primary-button {
    color: white;
    background: var(--green-900);
}

.secondary-button {
    background: white;
    border: 1px solid var(--border);
}


/* HERO PANEL */

.hero-panel {
    padding: 30px;

    color: white;

    background:
        linear-gradient(
            145deg,
            var(--green-900),
            var(--green-700)
        );

    border-radius: 22px;

    box-shadow:
        0 25px 60px
        rgba(23, 75, 56, 0.18);
}

.hero-panel-label {
    font-size: 12px;
    letter-spacing: .13em;
    opacity: .75;
}

.hero-stat {
    margin: 30px 0;
}

.hero-stat span {
    display: block;
    opacity: .8;
}

.hero-stat strong {
    display: inline-block;
    margin-top: 4px;

    font-size: 70px;
    line-height: 1;
}

.hero-stat small {
    margin-left: 7px;
    opacity: .65;
}

.hero-note {
    padding-top: 20px;

    border-top:
        1px solid
        rgba(255, 255, 255, 0.18);

    line-height: 1.7;
    font-size: 13px;

    opacity: .8;
}


/* SECTIONS */

.section-block {
    padding: 75px 0 10px;
}

.section-heading {
    margin-bottom: 30px;
}

.section-heading h2 {
    margin: 7px 0 10px;

    font-size: 34px;
}

.section-heading p {
    margin: 0;
    color: var(--muted);
}

.eyebrow {
    color: var(--green-700);

    font-size: 12px;
    font-weight: 800;

    letter-spacing: .15em;
}


/* FEATURES */

.feature-grid {
    display: grid;

    grid-template-columns:
        repeat(3, 1fr);

    gap: 18px;
}

.feature-card {
    padding: 28px;

    background: white;

    border:
        1px solid
        var(--border);

    border-radius: 16px;
}

.feature-number {
    font-size: 13px;
    color: var(--green-700);
    font-weight: 800;
}

.feature-card h3 {
    margin: 18px 0 10px;
    font-size: 20px;
}

.feature-card p {
    margin: 0;

    color: var(--muted);

    line-height: 1.75;
}


/* CATEGORY */

.category-grid {
    display: grid;
    grid-template-columns:
        repeat(2, 1fr);

    gap: 17px;
}

.category-card {
    display: flex;
    align-items: center;

    padding: 23px;

    background: white;

    border:
        1px solid
        var(--border);

    border-radius: 15px;

    transition:
        transform .18s ease,
        box-shadow .18s ease;
}

.category-card:hover {
    transform: translateY(-3px);

    box-shadow:
        0 14px 34px
        rgba(0, 0, 0, .06);
}

.category-index {
    width: 48px;

    color: var(--green-700);

    font-weight: 800;
    font-size: 14px;
}

.category-text h3 {
    margin: 0 0 5px;
}

.category-text p {
    margin: 0;

    color: var(--muted);

    font-size: 14px;
}

.category-arrow {
    margin-left: auto;

    font-size: 24px;
    color: var(--green-700);
}


/* FUTURE */

.future-section {
    margin-top: 100px;
    padding: 80px 0;

    color: white;

    background: var(--green-900);
}

.section-heading.light .eyebrow {
    color: #94d5b5;
}

.future-grid {
    display: grid;

    grid-template-columns:
        repeat(4, 1fr);

    gap: 15px;
}

.future-item {
    padding: 25px;

    background:
        rgba(255, 255, 255, .06);

    border:
        1px solid
        rgba(255, 255, 255, .12);

    border-radius: 14px;
}

.future-item h3 {
    margin-top: 0;
}

.future-item p {
    margin-bottom: 0;

    line-height: 1.7;

    color:
        rgba(255, 255, 255, .72);
}


/* QUIZ */

.quiz-container {
    max-width: 860px;

    padding-top: 55px;
    padding-bottom: 80px;
}

.quiz-heading {
    margin-bottom: 38px;
}

.quiz-heading h1 {
    margin: 8px 0 8px;

    font-size: 40px;
}

.quiz-heading p {
    color: var(--muted);
    line-height: 1.7;
}

.back-link {
    display: inline-block;

    margin-bottom: 26px;

    color: var(--green-700);

    font-weight: 700;
}

.quiz-category {
    color: var(--muted);
    font-size: 14px;
}


/* QUESTION CARD */

.quiz-card {
    margin-bottom: 30px;
    padding: 34px;

    background: white;

    border:
        1px solid
        var(--border);

    border-radius: 18px;
}

.question-meta {
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.question-number {
    color: var(--green-700);

    font-size: 12px;
    font-weight: 800;

    letter-spacing: .12em;
}

.question-category {
    padding: 5px 9px;

    background: var(--green-100);

    border-radius: 999px;

    color: var(--green-700);

    font-size: 12px;
}

.question-text {
    margin: 22px 0 27px;

    font-size: 22px;
    line-height: 1.65;
}


/* CHOICES */

.choices {
    display: grid;
    gap: 12px;
}

.choice-button {
    width: 100%;

    display: flex;
    align-items: center;

    gap: 14px;

    padding: 16px;

    text-align: left;

    background: white;

    border:
        1px solid
        var(--border);

    border-radius: 11px;

    cursor: pointer;

    transition:
        background .15s ease,
        border .15s ease;
}

.choice-button:hover:not(:disabled) {
    background: #f2f8f4;
    border-color: #91bea6;
}

.choice-button:disabled {
    cursor: default;
}

.choice-label {
    width: 32px;
    height: 32px;

    flex-shrink: 0;

    display: flex;
    align-items: center;
    justify-content: center;

    border-radius: 8px;

    background: #eef2f0;

    font-weight: 800;
}

.choice-text {
    line-height: 1.55;
}

.choice-button.correct {
    background: #effcf3;
    border-color: #22c55e;
}

.choice-button.incorrect {
    background: #fff1f1;
    border-color: #ef4444;
}


/* RESULT */

.result-box {
    display: none;

    margin-top: 25px;
    padding: 21px;

    border-radius: 12px;
}

.result-box.show {
    display: block;
}

.correct-result {
    background: #effcf3;
}

.incorrect-result {
    background: #fff1f1;
}

.result-title {
    margin-bottom: 16px;

    font-size: 20px;
    font-weight: 800;
}

.explanation-label {
    margin-bottom: 6px;

    font-size: 13px;
    font-weight: 800;
}

.explanation p {
    margin: 0;

    line-height: 1.75;
}


/* MISC */

.empty-card {
    padding: 30px;

    background: white;

    border: 1px solid var(--border);

    border-radius: 15px;
}

footer {
    padding: 30px 0;

    background: white;

    border-top: 1px solid var(--border);

    color: var(--muted);

    font-size: 13px;
}

.footer-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
}


/* RESPONSIVE */

@media (max-width: 850px) {

    .hero-inner {
        grid-template-columns: 1fr;
    }

    .hero-panel {
        max-width: 500px;
    }

    .feature-grid,
    .future-grid {
        grid-template-columns: 1fr 1fr;
    }
}

@media (max-width: 650px) {

    .hero {
        padding: 65px 0;
    }

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

    .category-grid,
    .feature-grid,
    .future-grid {
        grid-template-columns: 1fr;
    }

    .quiz-card {
        padding: 23px;
    }

    .footer-inner {
        align-items: flex-start;
        flex-direction: column;
        gap: 5px;
    }
}