/* Concept Page Styles */
@import url('https://fonts.googleapis.com/css2?family=Noto+Sans+JP:wght@400;500;700;900&family=Oswald:wght@500;700&display=swap');

.yi-concept-page {
    background-color: #0d0d0d;
    color: #ffffff;
    font-family: 'Noto Sans JP', sans-serif;
    padding-top: 64px;
    /* Offset for fixed header */
}

.yi-concept-problem {
    background: #111318;
}

.yi-container {
    width: 100%;
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 20px;
}

.yi-section {
    padding: 100px 0;
}

.yi-section-header {
    margin-bottom: 50px;
}

.yi-section-subtitle {
    color: var(--primary-color);
    font-family: 'Oswald', sans-serif;
    font-size: 14px;
    letter-spacing: 2px;
    display: block;
    margin-bottom: 10px;
}

.yi-section-title {
    font-size: 32px;
    font-weight: 700;
    color: #ffffff;
    margin: 0 0 20px 0;
    line-height: 1.4;
}

.yi-section-line {
    width: 40px;
    height: 3px;
    background-color: var(--primary-color);
}

/* Hero Section */
.yi-concept-hero {
    text-align: center;
    padding: 120px 0 80px;
    background: linear-gradient(180deg, #1a0800 0%, #0a0a0a 100%);
}

.yi-concept-subtitle {
    color: var(--primary-color);
    font-family: 'Oswald', sans-serif;
    font-size: 14px;
    font-weight: 500;
    letter-spacing: 4px;
    display: block;
    margin-bottom: 20px;
}

.yi-concept-title {
    font-size: clamp(2.5rem, 6vw, 5rem);
    font-weight: 900;
    line-height: 1.2;
    margin: 0 0 30px 0;
    letter-spacing: -1px;
}

.yi-concept-hero-desc {
    font-size: 16px;
    color: #cccccc;
    line-height: 1.8;
    margin: 0 auto;
    max-width: 700px;
}

/* Stats Grid */
.yi-stats-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
    margin-bottom: 40px;
}

.yi-stat-card {
    background-color: #1a1a1c;
    border-radius: 8px;
    padding: 40px 30px;
    text-align: center;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.yi-stat-number {
    font-size: 48px;
    font-weight: 900;
    color: var(--primary-color);
    margin-bottom: 15px;
    font-family: 'Noto Sans JP', sans-serif;
}

.yi-stat-number span {
    font-size: 24px;
}

.yi-stat-title {
    font-size: 16px;
    font-weight: 700;
    margin: 0 0 15px 0;
}

.yi-stat-desc {
    font-size: 13px;
    color: #aaaaaa;
    line-height: 1.6;
    margin: 0;
}

.yi-problem-footer-text {
    font-size: 14px;
    color: #cccccc;
    line-height: 1.8;
    max-width: 800px;
}

/* Mission Box */
.yi-mission-box {
    background-color: #15110e;
    border: 1px solid rgba(255, 92, 22, 0.15);
    border-radius: 8px;
    padding: 60px 40px;
    text-align: center;
}

.yi-mission-text {
    font-size: 32px;
    font-weight: 700;
    line-height: 1.6;
    margin: 0 0 30px 0;
}

.yi-mission-desc {
    font-size: 15px;
    color: #cccccc;
    line-height: 1.8;
    max-width: 800px;
    margin: 0 auto;
}

/* Diff Grid */
.yi-diff-grid {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 30px;
}

.yi-diff-card {
    background-color: #1a1a1c;
    border-radius: 8px;
    padding: 40px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.yi-diff-card.new-way {
    background-color: #1a1512;
    border-color: rgba(255, 92, 22, 0.3);
}

.yi-diff-badge {
    display: inline-block;
    padding: 5px 15px;
    border-radius: 3px;
    font-size: 12px;
    font-weight: 500;
    margin-bottom: 20px;
}

.old-way .yi-diff-badge {
    background-color: #333333;
    color: #aaaaaa;
}

.new-way .yi-diff-badge {
    background-color: rgba(255, 92, 22, 0.2);
    color: var(--primary-color);
    border: 1px solid rgba(255, 92, 22, 0.5);
}

.yi-diff-title {
    font-size: 24px;
    font-weight: 700;
    margin: 0 0 30px 0;
}

.yi-diff-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.yi-diff-list li {
    font-size: 15px;
    color: #cccccc;
    margin-bottom: 15px;
    padding-bottom: 15px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.05);
    display: flex;
    align-items: flex-start;
    gap: 10px;
}

.yi-diff-list li:last-child {
    border-bottom: none;
    margin-bottom: 0;
    padding-bottom: 0;
}

.old-way .yi-diff-list li::before {
    content: "−";
    color: #555555;
    font-weight: bold;
}

.yi-check {
    color: var(--primary-color);
    font-weight: bold;
}

/* Values Grid */
.yi-values-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.yi-value-card {
    background-color: #1a1a1c;
    border-radius: 8px;
    padding: 40px 30px;
    border: 1px solid rgba(255, 255, 255, 0.05);
}

.yi-value-number {
    font-size: 32px;
    font-weight: 700;
    color: rgba(255, 92, 22, 0.5);
    font-family: 'Oswald', sans-serif;
    margin-bottom: 10px;
}

.yi-value-title {
    font-size: 18px;
    font-weight: 700;
    margin: 0 0 15px 0;
    font-family: 'Oswald', sans-serif;
    letter-spacing: 1px;
}

.yi-value-desc {
    font-size: 13px;
    color: #aaaaaa;
    line-height: 1.6;
    margin: 0;
}

/* CTA */
.yi-concept-cta {
    text-align: center;
    padding: 100px 20px 120px;
}

.yi-cta-title {
    font-size: 36px;
    font-weight: 700;
    margin: 0 0 15px 0;
}

.yi-cta-title span {
    color: var(--primary-color);
}

.yi-cta-desc {
    font-size: 15px;
    color: #aaaaaa;
    margin: 0 0 40px 0;
}

.yi-cta-buttons {
    display: flex;
    gap: 20px;
    justify-content: center;
}

.yi-btn {
    padding: 16px 40px;
    border-radius: 4px;
    font-size: 15px;
    font-weight: 700;
    text-decoration: none;
    transition: all 0.3s ease;
    cursor: pointer;
    border: 1px solid transparent;
}

.yi-btn-primary {
    background-color: var(--primary-color);
    color: #ffffff;
}

.yi-btn-primary:hover {
    background-color: #e04e0f;
    color: #ffffff;
    transform: translateY(-5px);
    box-shadow: 0 10px 20px rgba(255, 92, 22, 0.3);
}

.yi-btn-outline {
    background-color: transparent;
    border: 1px solid #555555;
    color: #ffffff;
}

.yi-btn-outline:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: #ffffff;
    color: #ffffff;
}

@media (max-width: 992px) {

    .yi-stats-grid,
    .yi-values-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .yi-concept-title {
        font-size: 40px;
    }

    .yi-mission-text {
        font-size: 24px;
    }

    .yi-stats-grid,
    .yi-diff-grid,
    .yi-values-grid {
        grid-template-columns: 1fr;
    }

    .yi-cta-buttons {
        flex-direction: column;
    }

    .yi-cta-buttons .yi-btn {
        width: 100%;
        box-sizing: border-box;
    }
}