* {
    box-sizing: border-box;
}

:root {
    --background: #B6DFF1;
    --cream: #FFF9D6;
    --text: #000000;
    --muted-text: rgba(0, 0, 0, 0.66);
    --border: rgba(0, 0, 0, 0.24);
    --expiration-soon: #FFD6A5;
    --expiration-expired: #FFB3BA;
    --content-width: 1320px;
}

html {
    scroll-behavior: smooth;
}

body {
    min-height: 100vh;
    margin: 0;
    display: flex;
    flex-direction: column;
    background-color: var(--background);
    color: var(--text);
    font-family: Inter, -apple-system, BlinkMacSystemFont, "Segoe UI", Arial, sans-serif;
    line-height: 1.5;
}

img {
    display: block;
    max-width: 100%;
}

a {
    color: inherit;
}

/* Header */

.site-header {
    width: min(var(--content-width), calc(100% - 80px));
    margin: 0 auto;
    padding: 32px 0;
    display: flex;
    align-items: center;
    justify-content: space-between;
    border-bottom: 1px solid var(--border);
}

.site-name {
    font-size: 17px;
    font-weight: 800;
    letter-spacing: -0.02em;
    text-decoration: none;
}

.site-header nav {
    display: flex;
    align-items: center;
    gap: 32px;
}

    .site-header nav a {
        padding: 6px 0;
        font-size: 15px;
        font-weight: 600;
        text-decoration: none;
        border-bottom: 1px solid transparent;
    }

        .site-header nav a:hover,
        .site-header nav a:focus-visible {
            border-bottom-color: var(--text);
        }

/* Main layout */

main {
    width: min(var(--content-width), calc(100% - 80px));
    margin: auto;
}

/* Homepage hero */

.hero {
    min-height: 650px;
    padding: 50px 0 110px;
    display: grid;
    grid-template-columns: minmax(0, 0.9fr) minmax(420px, 1.1fr);
    align-items: center;
    gap: 56px;
}

.hero-text {
    position: relative;
    z-index: 1;
}

.hero h1 {
    max-width: 690px;
    margin: 0;
    font-size: clamp(48px, 5.4vw, 84px);
    font-weight: 800;
    letter-spacing: -0.055em;
    line-height: 0.97;
}

    .hero h1 span {
        display: block;
    }

.hero p {
    max-width: 470px;
    margin: 28px 0 0;
    color: var(--muted-text);
    font-size: clamp(18px, 1.5vw, 23px);
    line-height: 1.5;
}

.text-link {
    display: inline-block;
    margin-top: 28px;
    font-size: 16px;
    font-weight: 700;
    text-decoration-line: underline;
    text-decoration-thickness: 1px;
    text-underline-offset: 5px;
}

    .text-link:hover,
    .text-link:focus-visible {
        text-decoration-thickness: 2px;
    }

.hero-image {
    display: flex;
    align-items: center;
    justify-content: center;
}

    .hero-image img {
        width: min(100%, 850px);
        max-height: 720px;
        object-fit: contain;
    }

/* Tutorial page */

.tutorial {
    padding: 90px 0 120px;
}

.tutorial-introduction {
    margin-bottom: 80px;
    display: grid;
    grid-template-columns: minmax(0, 1fr) minmax(240px, 380px);
    align-items: center;
    gap: 72px;
}

.tutorial-introduction-copy {
    max-width: 760px;
}

.section-label {
    margin: 0 0 14px;
    font-size: 13px;
    font-weight: 800;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.tutorial-introduction h1 {
    margin: 0;
    max-width: 760px;
    font-size: clamp(42px, 5vw, 68px);
    font-weight: 800;
    letter-spacing: -0.045em;
    line-height: 1.02;
}

.tutorial-introduction-copy > p:last-child {
    max-width: 620px;
    margin: 24px 0 0;
    color: var(--muted-text);
    font-size: 19px;
    line-height: 1.55;
}

.tutorial-introduction-image {
    display: flex;
    align-items: center;
    justify-content: center;
}

    .tutorial-introduction-image img {
        width: 100%;
        max-width: 340px;
        height: auto;
        object-fit: contain;
    }

.tutorial-steps {
    border-top: 1px solid var(--border);
}

.tutorial-step {
    padding: 52px 0;
    display: grid;
    grid-template-columns: 100px minmax(0, 700px);
    gap: 36px;
    border-bottom: 1px solid var(--border);
}

.step-number {
    margin: 5px 0 0;
    font-size: 15px;
    font-weight: 800;
    letter-spacing: 0.05em;
}

.step-content h2 {
    margin: 0 0 14px;
    font-size: clamp(30px, 3vw, 43px);
    font-weight: 800;
    letter-spacing: -0.035em;
    line-height: 1.1;
}

.step-content > p {
    max-width: 650px;
    margin: 0;
    color: var(--muted-text);
    font-size: 18px;
    line-height: 1.65;
}

/* Expiration guide */

.expiration-guide {
    margin-top: 24px;
}

.expiration-explanation {
    margin: 0 0 12px;
    color: var(--muted-text);
    font-size: 15px;
    font-weight: 600;
    line-height: 1.5;
}

.expiration-key {
    display: flex;
    flex-wrap: wrap;
    gap: 12px;
}

.expiration-status {
    display: inline-flex;
    align-items: center;
    min-height: 38px;
    padding: 9px 15px;
    border: 1px solid rgba(0, 0, 0, 0.55);
    border-radius: 999px;
    color: var(--text);
    font-size: 14px;
    font-weight: 700;
    line-height: 1.2;
}

.expiration-soon {
    background-color: var(--expiration-soon);
}

.expiration-expired {
    background-color: var(--expiration-expired);
}

/* Footer */

.site-footer {
    width: min(var(--content-width), calc(100% - 80px));
    margin: 0 auto;
    padding: 26px 0 34px;
    display: grid;
    grid-template-columns: 1fr auto auto;
    align-items: center;
    gap: 34px;
    border-top: 1px solid var(--border);
    font-size: 14px;
}

    .site-footer p {
        margin: 0;
    }

    .site-footer a {
        text-decoration: none;
    }

        .site-footer a:hover,
        .site-footer a:focus-visible {
            text-decoration: underline;
            text-underline-offset: 4px;
        }

/* Privacy page */

.privacy-main {
    padding: 50px 0 90px;
}

.privacy-card {
    max-width: 850px;
    margin: 0 auto;
    padding: clamp(32px, 6vw, 72px);
}

    .privacy-card h1 {
        margin: 0 0 8px;
        font-size: clamp(42px, 6vw, 72px);
        letter-spacing: -0.04em;
        line-height: 1;
    }

    .privacy-card h2 {
        margin: 42px 0 12px;
        font-size: 24px;
        line-height: 1.2;
    }

    .privacy-card p,
    .privacy-card li {
        font-size: 17px;
    }

    .privacy-card a {
        text-underline-offset: 4px;
    }

.updated {
    margin-bottom: 36px;
    color: var(--muted-text);
}

/* Tablet */

@media (max-width: 900px) {
    .site-header,
    main,
    .site-footer {
        width: min(calc(100% - 40px), var(--content-width));
    }

    .site-header {
        padding: 24px 0;
    }

    .hero {
        min-height: auto;
        padding: 48px 0 82px;
        grid-template-columns: 1fr;
        gap: 38px;
    }

        .hero h1 {
            max-width: 100%;
            font-size: clamp(48px, 11vw, 74px);
        }

        .hero p {
            max-width: 540px;
            font-size: 18px;
        }

    .hero-image img {
        width: min(100%, 540px);
        max-height: none;
    }

    .tutorial {
        padding: 72px 0 90px;
    }

    .tutorial-introduction {
        margin-bottom: 60px;
        grid-template-columns: 1fr;
        gap: 36px;
    }

    .tutorial-introduction-image {
        justify-content: flex-start;
    }

        .tutorial-introduction-image img {
            max-width: 260px;
        }

    .tutorial-step {
        grid-template-columns: 70px minmax(0, 1fr);
        gap: 24px;
    }

    .site-footer {
        grid-template-columns: 1fr;
        gap: 10px;
    }

    .privacy-main {
        padding: 32px 0 60px;
    }
}

/* Mobile */

@media (max-width: 600px) {
    .site-header,
    main,
    .site-footer {
        width: calc(100% - 32px);
    }

    .site-header {
        padding: 20px 0;
    }

    .site-name {
        font-size: 15px;
    }

    .site-header nav {
        gap: 18px;
    }

        .site-header nav a {
            font-size: 13px;
        }

    .hero {
        padding: 34px 0 64px;
        gap: 30px;
    }

        .hero h1 {
            font-size: clamp(42px, 14vw, 60px);
            letter-spacing: -0.045em;
        }

        .hero p {
            margin-top: 20px;
            font-size: 17px;
        }

    .text-link {
        margin-top: 24px;
        font-size: 15px;
    }

    .hero-image img {
        width: 100%;
        max-width: 420px;
    }

    .tutorial {
        padding: 54px 0 70px;
    }

    .tutorial-introduction {
        margin-bottom: 46px;
        gap: 28px;
    }

        .tutorial-introduction h1 {
            font-size: 38px;
        }

    .tutorial-introduction-copy > p:last-child {
        margin-top: 18px;
        font-size: 17px;
    }

    .tutorial-introduction-image img {
        max-width: 220px;
    }

    .tutorial-step {
        padding: 38px 0;
        grid-template-columns: 1fr;
        gap: 10px;
    }

    .step-number {
        margin: 0;
        font-size: 13px;
    }

    .step-content h2 {
        margin-bottom: 12px;
        font-size: 30px;
    }

    .step-content > p {
        font-size: 16px;
        line-height: 1.6;
    }

    .expiration-guide {
        margin-top: 20px;
    }

    .expiration-explanation {
        margin-bottom: 10px;
        font-size: 14px;
    }

    .expiration-key {
        gap: 10px;
    }

    .expiration-status {
        min-height: 36px;
        padding: 8px 12px;
        font-size: 13px;
    }

    .site-footer {
        padding-bottom: 28px;
        font-size: 13px;
    }

    .privacy-card {
        padding: 28px 22px;
    }

        .privacy-card h1 {
            font-size: 42px;
        }

        .privacy-card h2 {
            margin-top: 34px;
            font-size: 22px;
        }

        .privacy-card p,
        .privacy-card li {
            font-size: 16px;
        }
}