/* =======================================
   Mobile-First Apple-inspired Design
   ======================================= */

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

:root {
    --color-text-primary: #1d1d1f;
    --color-text-secondary: #86868b;
    --color-bg-white: #ffffff;
    --color-bg-light: #f5f5f7;
    --color-bg-dark: #000000;
    --color-orange: #ff6b35;
    --color-blue: #0071e3;
    --color-green: #34c759;
    --font-main: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    --transition-smooth: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: var(--font-main);
    color: var(--color-text-primary);
    background-color: var(--color-bg-white);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
    font-size: 16px;
}

/* =======================================
   Container - Mobile First
   ======================================= */

.container {
    max-width: 100%;
    margin: 0 auto;
    padding: 0 20px;
}

/* =======================================
   Hero Section - Mobile First
   ======================================= */

.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 60px 0 80px;
    background: linear-gradient(135deg, #f5f5f7 0%, #ffffff 100%);
    animation: fadeIn 1s ease-out;
}

.hero-title {
    font-size: 40px;
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.1;
    margin-bottom: 20px;
    color: var(--color-text-primary);
    animation: slideUp 1s ease-out 0.2s both;
}

.hero-subtitle {
    font-size: 22px;
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.3;
    margin-bottom: 24px;
    color: var(--color-text-secondary);
    animation: slideUp 1s ease-out 0.4s both;
}

.hero-description {
    font-size: 17px;
    font-weight: 400;
    line-height: 1.7;
    color: var(--color-text-secondary);
    animation: slideUp 1s ease-out 0.6s both;
}

/* =======================================
   Benefit Section - Mobile First
   ======================================= */

.benefit {
    padding: 60px 0;
    background-color: var(--color-bg-white);
    text-align: center;
}

.section-title {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.2;
    margin-bottom: 28px;
    color: var(--color-text-primary);
}

.section-description {
    font-size: 17px;
    font-weight: 400;
    line-height: 1.8;
    color: var(--color-text-secondary);
}

/* =======================================
   Steps Section - Mobile First
   ======================================= */

.steps {
    padding: 60px 0 40px;
    background-color: var(--color-bg-light);
    text-align: center;
}

.section-title-large {
    font-size: 36px;
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.15;
    color: var(--color-text-primary);
    padding: 0 10px;
}

/* =======================================
   Step Sections - Mobile First
   ======================================= */

.step {
    padding: 60px 0;
    text-align: center;
    background-color: var(--color-bg-white);
    transition: var(--transition-smooth);
}

.step-dark {
    background-color: var(--color-bg-dark);
}

.step-dark .step-number,
.step-dark .step-title,
.step-dark .step-title-large,
.step-dark .step-description {
    color: var(--color-bg-white);
}

.step-content {
    opacity: 0;
    transform: translateY(50px);
    animation: fadeInUp 1s ease-out forwards;
}

.step.visible .step-content {
    opacity: 1;
    transform: translateY(0);
}

.step-number {
    font-size: 24px;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    color: var(--color-text-secondary);
    margin-bottom: 20px;
}

.step-title {
    font-size: 40px;
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.2;
    margin-bottom: 24px;
    color: var(--color-text-primary);
}

.step-title-large {
    font-size: 24px;
    font-weight: 600;
    letter-spacing: -0.02em;
    line-height: 1.3;
    margin-bottom: 24px;
    color: var(--color-text-primary);
}

.step-description {
    font-size: 17px;
    font-weight: 400;
    line-height: 1.8;
    color: var(--color-text-secondary);
    margin-bottom: 36px;
}

/* =======================================
   CTA Buttons - Mobile First (タップ最適化)
   ======================================= */

.cta-button {
    display: inline-block;
    width: 100%;
    max-width: 340px;
    padding: 18px 32px;
    font-size: 17px;
    font-weight: 600;
    text-decoration: none;
    border-radius: 980px;
    transition: var(--transition-smooth);
    border: none;
    cursor: pointer;
    letter-spacing: -0.01em;
    min-height: 56px;
    line-height: 1.2;
    position: relative;
    overflow: hidden;
    -webkit-tap-highlight-color: transparent;
    touch-action: manipulation;
}

.cta-button::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(255, 255, 255, 0.15);
    transform: translateX(-100%);
    transition: transform 0.3s ease;
}

.cta-button:active {
    transform: scale(0.97);
}

.cta-orange {
    background-color: var(--color-orange);
    color: white;
}

.cta-orange:active {
    background-color: #ff5722;
}

.cta-blue {
    background-color: var(--color-blue);
    color: white;
}

.cta-blue:active {
    background-color: #0062cc;
}

.cta-green {
    background-color: var(--color-green);
    color: white;
}

.cta-green:active {
    background-color: #2ab04a;
}

.cta-final {
    background-color: var(--color-text-primary);
    color: white;
    padding: 20px 32px;
    font-size: 18px;
    max-width: 360px;
}

.cta-final:active {
    background-color: #42424a;
}

/* =======================================
   FAQ Section - Mobile First
   ======================================= */

.faq {
    padding: 60px 0;
    background-color: var(--color-bg-light);
    text-align: center;
}

.faq .section-title-large {
    margin-bottom: 48px;
}

.faq-item {
    margin: 0 0 40px;
    padding-bottom: 40px;
    border-bottom: 1px solid #d2d2d7;
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.8s ease-out forwards;
}

.faq-item:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.faq-question {
    font-size: 20px;
    font-weight: 600;
    letter-spacing: -0.01em;
    line-height: 1.4;
    margin-bottom: 12px;
    color: var(--color-text-primary);
    text-align: left;
}

.faq-answer {
    font-size: 16px;
    font-weight: 400;
    line-height: 1.7;
    color: var(--color-text-secondary);
    text-align: left;
}

/* =======================================
   Final Message Section - Mobile First
   ======================================= */

.final-message {
    padding: 60px 0;
    background-color: var(--color-bg-white);
    text-align: center;
}

.final-title {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.03em;
    line-height: 1.2;
    margin-bottom: 32px;
    color: var(--color-text-primary);
}

.final-description {
    font-size: 17px;
    font-weight: 400;
    line-height: 1.8;
    color: var(--color-text-secondary);
}

.final-description strong {
    color: var(--color-text-primary);
    font-weight: 600;
}

/* =======================================
   Final CTA Section - Mobile First
   ======================================= */

.final-cta {
    padding: 60px 0 80px;
    background: linear-gradient(135deg, #f5f5f7 0%, #e8e8ed 100%);
    text-align: center;
}

.cta-title {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.25;
    margin-bottom: 16px;
    color: var(--color-text-primary);
}

.cta-title-sub {
    font-size: 32px;
    font-weight: 700;
    letter-spacing: -0.02em;
    line-height: 1.25;
    margin-bottom: 24px;
    color: var(--color-text-primary);
}

.cta-description {
    font-size: 17px;
    font-weight: 400;
    line-height: 1.8;
    color: var(--color-text-secondary);
    margin-bottom: 36px;
}

/* =======================================
   Footer - Mobile First
   ======================================= */

.footer {
    padding: 32px 0;
    background-color: var(--color-bg-light);
    text-align: center;
}

.footer p {
    font-size: 13px;
    color: var(--color-text-secondary);
}

/* =======================================
   Animations
   ======================================= */

@keyframes fadeIn {
    from {
        opacity: 0;
    }
    to {
        opacity: 1;
    }
}

@keyframes slideUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(40px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* =======================================
   Tablet (タブレット向け調整)
   ======================================= */

@media (min-width: 481px) {
    .container {
        padding: 0 32px;
    }

    .hero-title {
        font-size: 48px;
    }

    .hero-subtitle {
        font-size: 26px;
    }

    .hero-description {
        font-size: 19px;
    }

    .section-title {
        font-size: 40px;
    }

    .section-description {
        font-size: 19px;
    }

    .section-title-large {
        font-size: 48px;
    }

    .step-number {
        font-size: 28px;
    }

    .step-title {
        font-size: 48px;
    }

    .step-title-large {
        font-size: 28px;
    }

    .cta-title-sub {
        font-size: 40px;
    }

    .step-description {
        font-size: 19px;
    }

    .faq-question {
        font-size: 24px;
    }

    .faq-answer {
        font-size: 18px;
    }

    .final-title {
        font-size: 40px;
    }

    .cta-title {
        font-size: 40px;
    }

    .cta-button {
        max-width: 380px;
        font-size: 18px;
    }
}

/* =======================================
   Desktop (デスクトップ向け拡張)
   ======================================= */

@media (min-width: 769px) {
    .container {
        max-width: 1200px;
        padding: 0 48px;
    }

    .hero {
        padding: 100px 0 120px;
    }

    .hero-title {
        font-size: 72px;
        margin-bottom: 24px;
    }

    .hero-subtitle {
        font-size: 36px;
        margin-bottom: 32px;
    }

    .hero-description {
        font-size: 22px;
        max-width: 700px;
        margin: 0 auto;
    }

    .benefit,
    .steps,
    .step,
    .faq,
    .final-message,
    .final-cta {
        padding: 100px 0;
    }

    .section-title {
        font-size: 52px;
        margin-bottom: 40px;
    }

    .section-description {
        font-size: 22px;
        max-width: 800px;
        margin: 0 auto;
    }

    .section-title-large {
        font-size: 72px;
    }

    .step-content {
        max-width: 700px;
        margin: 0 auto;
    }

    .step-number {
        font-size: 32px;
    }

    .step-title {
        font-size: 64px;
        margin-bottom: 32px;
    }

    .step-title-large {
        font-size: 32px;
    }

    .faq .section-title-large {
        margin-bottom: 64px;
    }

    .cta-title-sub {
        font-size: 56px;
    }

    .step-description {
        font-size: 22px;
        margin-bottom: 48px;
    }

    .cta-button {
        max-width: 420px;
        padding: 18px 48px;
        font-size: 19px;
        min-height: 58px;
    }

    .cta-button:hover::before {
        transform: translateX(0);
    }

    .cta-button:hover {
        transform: scale(1.02);
    }

    .cta-button:active {
        transform: scale(0.98);
    }

    .cta-final {
        padding: 20px 64px;
        font-size: 21px;
        max-width: 450px;
    }

    .faq-item {
        max-width: 800px;
        margin: 0 auto 56px;
        padding-bottom: 56px;
    }

    .faq-question {
        font-size: 30px;
        margin-bottom: 16px;
        text-align: center;
    }

    .faq-answer {
        font-size: 22px;
        text-align: center;
    }

    .final-title {
        font-size: 64px;
        margin-bottom: 48px;
    }

    .final-description {
        font-size: 22px;
        max-width: 700px;
        margin: 0 auto;
    }

    .cta-title {
        font-size: 56px;
        margin-bottom: 32px;
    }

    .cta-description {
        font-size: 22px;
        margin-bottom: 48px;
    }

    .final-cta {
        padding: 120px 0 140px;
    }
}

/* =======================================
   Large Desktop (大画面向け最適化)
   ======================================= */

@media (min-width: 1200px) {
    .hero-title {
        font-size: 96px;
    }

    .hero-subtitle {
        font-size: 40px;
    }

    .hero-description {
        font-size: 24px;
    }

    .section-title {
        font-size: 56px;
    }

    .section-description {
        font-size: 24px;
    }

    .section-title-large {
        font-size: 80px;
    }

    .step-number {
        font-size: 36px;
    }

    .step-title {
        font-size: 72px;
    }

    .step-title-large {
        font-size: 36px;
    }

    .cta-title-sub {
        font-size: 64px;
    }

    .step-description {
        font-size: 24px;
    }

    .faq-question {
        font-size: 32px;
    }

    .faq-answer {
        font-size: 24px;
    }

    .final-title {
        font-size: 72px;
    }

    .final-description {
        font-size: 24px;
    }

    .cta-title {
        font-size: 64px;
    }

    .cta-description {
        font-size: 24px;
    }

    .cta-button {
        font-size: 21px;
    }

    .cta-final {
        font-size: 24px;
    }
}

/* =======================================
   Scroll Animations
   ======================================= */

.fade-in-section {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 1s ease-out, transform 1s ease-out;
}

.fade-in-section.is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* =======================================
   Touch Optimization (タッチ最適化)
   ======================================= */

@media (hover: none) and (pointer: coarse) {
    /* タッチデバイス専用の最適化 */
    .cta-button {
        min-height: 58px;
    }
    
    .cta-button:hover {
        transform: none;
    }
    
    .cta-button:hover::before {
        transform: translateX(-100%);
    }
}