body {
  font-family: Arial, sans-serif;
  background-color: #f4f4f4;
  text-align: center;
}

#book-box-container {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  margin-top: 20px;
  width: 100%;
  margin-left: auto;
  margin-right: auto;

}
.main-container {
    width: min(1180px, calc(100% - 2rem));
    margin: clamp(7rem, 10vw, 10rem) auto 3rem;
    padding: clamp(1.25rem, 3vw, 2.5rem);
    box-sizing: border-box;
    background-color: var(--white, #ffffff);
    border-radius: 20px;
}

.book-page-intro {
    max-width: 900px;
    margin: 0 auto 2.5rem;
    text-align: center;
}

.book-page-intro h1 {
    margin: 0 0 1rem;
    color: #0f172a;
    font-size: clamp(2rem, 5vw, 3.25rem);
    line-height: 1.15;
    font-weight: 800;
    letter-spacing: -0.035em;
}

.book-page-intro p {
    max-width: 780px;
    margin: 0 auto;
    color: #475569;
    font-size: clamp(1rem, 2vw, 1.15rem);
    line-height: 1.7;
}

#books-grid {
    display: grid;
    width: 100%;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 1.5rem;
    margin-top: 1.5rem;
}

        
        /* Disabled/Coming Soon style */
        .coming-soon {
            background-color: #6c757d;
            cursor: not-allowed;
        }
        .coming-soon:hover {
            background-color: #5a6268;
        }
        /* Go Back Button Style */
.seo-subject-info {
    max-width: 850px;        /* keep it readable on wide screens */
    margin: 25px auto;        /* center with some space above/below */
    padding: 20px 25px;       /* breathing room inside */
    background-color: #f9f9f9; /* subtle background for distinction */
    border-left: 4px solid #007bff; /* small visual highlight */
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0, 0, 0, 0.03); /* subtle shadow for depth */
    font-size: 16px;
    line-height: 1.7;
    color: #333;              /* readable text color */
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

/* Optional: responsive adjustments for mobile */
@media (max-width: 768px) {
    .seo-subject-info {
        padding: 15px 20px;
        font-size: 15px;
        margin: 20px 10px;
    }
}

/* SEO Content Styles Refined */
.book-selection-header {
    text-align: center;
    margin-bottom: 3rem;
    padding: 0 1rem;
}

.book-selection-header h2 {
    color: #0f172a;
    font-size: clamp(1.5rem, 5vw, 2.2rem);
    font-weight: 800;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.book-selection-header p {
    color: #64748b;
    font-size: clamp(1rem, 2.5vw, 1.15rem);
    max-width: 750px;
    margin: 0 auto;
    line-height: 1.6;
}

.book-features-seo {
    margin: 4rem auto 2rem auto;
    padding: 3rem 2rem;
    background: linear-gradient(135deg, #ffffff 0%, #f8fafc 100%);
    border-radius: 24px;
    border: 1px solid rgba(226, 232, 240, 0.8);
    box-shadow: 0 20px 50px -12px rgba(0, 0, 0, 0.05);
}

.features-title {
    color: #0f172a;
    font-size: clamp(1.3rem, 4vw, 1.75rem);
    font-weight: 800;
    margin-bottom: 3rem;
    text-align: center;
    letter-spacing: -0.01em;
}

.features-intro {
    max-width: 820px;
    margin: -2rem auto 3rem;
    color: #64748b;
    font-size: 1.1rem;
    line-height: 1.7;
    text-align: center;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 260px), 1fr));
    gap: 2rem;
}

.feature-card {
    display: block;
    padding: 1.75rem;
    background: #ffffff;
    border-radius: 20px;
    border: 1px solid #f1f5f9;
    transition: all 0.4s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.02);
}

.feature-card:hover {
    transform: translateY(-8px);
    border-color: #3b82f6;
    box-shadow: 0 20px 25px -5px rgba(59, 130, 246, 0.1), 0 10px 10px -5px rgba(59, 130, 246, 0.04);
}

.feature-text {
    text-align: left;
}

.feature-text strong {
    display: block;
    color: #0f172a;
    font-size: 1.15rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
}

.feature-text p {
    color: #475569;
    font-size: 0.95rem;
    line-height: 1.5;
    margin: 0;
}

.bise-boards-section {
    margin-top: 4rem;
    padding-top: 3rem;
    text-align: center;
    border-top: 1px solid #e2e8f0;
}

.bise-boards-section h3 {
    margin-bottom: 1.5rem;
    color: #0f172a;
}

.bise-boards-section p {
    max-width: 800px;
    margin: 0 auto 2rem;
    color: #475569;
    line-height: 1.6;
}

.boards-list {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 0.65rem;
    color: #1e40af;
    font-weight: 600;
}

.boards-list span {
    padding: 0.45rem 0.7rem;
    background: #eff6ff;
    border: 1px solid #dbeafe;
    border-radius: 999px;
}

.page-back-link {
    align-items: center;
    justify-content: center;
    text-decoration: none;
}

.class-nine-seo-article {
    width: min(1080px, calc(100% - 2rem));
    margin: 3rem auto;
    padding: clamp(1.5rem, 4vw, 3.5rem);
    box-sizing: border-box;
    color: #334155;
    text-align: left;
    line-height: 1.8;
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 24px;
    box-shadow: 0 18px 45px rgba(15, 23, 42, 0.08);
}

.class-nine-seo-article h2 {
    margin: 0 0 1rem;
    color: #0f172a;
    font-size: clamp(1.8rem, 4vw, 2.6rem);
    line-height: 1.2;
    letter-spacing: -0.025em;
}

.class-nine-seo-article h3 {
    margin: 2.75rem 0 1rem;
    color: #172554;
    font-size: clamp(1.35rem, 3vw, 1.85rem);
    line-height: 1.3;
}

.class-nine-seo-article h4 {
    margin: 0 0 0.65rem;
    color: #1e3a8a;
    font-size: 1.15rem;
    line-height: 1.4;
}

.class-nine-seo-article p,
.class-nine-seo-article li {
    color: #475569;
    font-size: 1rem;
}

.class-nine-seo-article p {
    margin: 0 0 1.15rem;
}

.class-nine-seo-article strong {
    color: #1e3a8a;
}

.class-nine-seo-article a {
    color: #1d4ed8;
}

.seo-article-header {
    padding-bottom: 1.5rem;
    border-bottom: 1px solid #e2e8f0;
}

.seo-eyebrow {
    margin-bottom: 0.45rem !important;
    color: #2563eb !important;
    font-size: 0.82rem !important;
    font-weight: 800;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.seo-article-lead {
    font-size: 1.08rem !important;
}

.seo-article-nav {
    display: flex;
    flex-wrap: wrap;
    gap: 0.65rem 1rem;
    margin-top: 1.5rem;
    padding: 1rem 1.15rem;
    background: #f8fafc;
    border-radius: 12px;
}

.seo-article-nav strong {
    width: 100%;
}

.seo-article-nav a {
    font-weight: 700;
    text-decoration: none;
}

.seo-article-nav a:hover,
.seo-article-nav a:focus {
    text-decoration: underline;
}

.seo-info-grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 1rem;
    margin: 1.75rem 0;
}

.seo-info-grid > div {
    padding: 1.3rem;
    background: #f8fafc;
    border: 1px solid #e2e8f0;
    border-radius: 14px;
}

.seo-info-grid p {
    margin-bottom: 0;
    font-size: 0.96rem;
}

.seo-callout {
    margin: 1.75rem 0;
    padding: 1.4rem 1.5rem;
    background: #eff6ff;
    border: 1px solid #bfdbfe;
    border-left: 5px solid #2563eb;
    border-radius: 12px;
}

.seo-callout p {
    margin-bottom: 0;
}

.subject-seo-card {
    margin: 1.25rem 0;
    padding: 1.5rem;
    background: linear-gradient(135deg, #ffffff, #f8fafc);
    border: 1px solid #dbeafe;
    border-radius: 16px;
}

.subject-seo-card + .subject-seo-card {
    margin-top: 1.5rem;
}

.subject-generator-link {
    display: inline-flex;
    align-items: center;
    padding: 0.7rem 1rem;
    color: #ffffff !important;
    font-weight: 700;
    line-height: 1.3;
    text-decoration: none;
    background: #2563eb;
    border-radius: 9px;
}

.subject-generator-link:hover,
.subject-generator-link:focus {
    background: #1d4ed8;
    transform: translateY(-1px);
}

.seo-process-list {
    margin: 1.25rem 0 1.75rem;
    padding-left: 1.4rem;
}

.seo-process-list li {
    margin-bottom: 0.85rem;
    padding-left: 0.3rem;
}

.seo-faq-section details {
    margin-bottom: 0.8rem;
    background: #ffffff;
    border: 1px solid #e2e8f0;
    border-radius: 11px;
}

.seo-faq-section summary {
    padding: 1rem 1.15rem;
    color: #1e3a8a;
    font-weight: 700;
    cursor: pointer;
}

.seo-faq-section details p {
    margin: 0;
    padding: 0 1.15rem 1rem;
}

.seo-article-footer {
    margin-top: 3rem;
    padding: 2rem;
    color: #ffffff;
    text-align: center;
    background: linear-gradient(135deg, #172554, #2563eb);
    border-radius: 16px;
}

.seo-article-footer h3,
.seo-article-footer p {
    color: #ffffff;
}

.seo-article-footer h3 {
    margin-top: 0;
}

.seo-article-footer a {
    display: inline-flex;
    padding: 0.75rem 1.15rem;
    color: #172554;
    font-weight: 800;
    text-decoration: none;
    background: #ffffff;
    border-radius: 9px;
}

@media (max-width: 768px) {
    .main-container {
        width: calc(100% - 1rem);
        margin-top: 6.5rem;
        padding: 1.25rem 0.9rem;
        border-radius: 14px;
    }

    .book-page-intro {
        margin-bottom: 2rem;
    }

    .book-page-intro h1 {
        font-size: clamp(1.75rem, 8vw, 2.35rem);
        letter-spacing: -0.025em;
    }

    .book-page-intro p {
        font-size: 0.98rem;
        line-height: 1.6;
    }

    #book-box-container {
        margin-top: 0;
    }

    #books-grid {
        grid-template-columns: 1fr;
        gap: 1rem;
    }

    .book-selection-header {
        margin-bottom: 2rem;
        padding: 0;
    }

    .book-selection-header h2 {
        font-size: 1.45rem;
    }

    .book-features-seo {
        padding: 2rem 1rem;
        margin-top: 2.5rem;
        border-radius: 16px;
    }
    
    .feature-card {
        padding: 1.25rem;
    }

    .features-intro {
        margin-top: -1.75rem;
        margin-bottom: 2rem;
        font-size: 1rem;
    }

    .bise-boards-section {
        margin-top: 2.5rem;
        padding-top: 2rem;
    }

    .boards-list {
        display: grid;
        grid-template-columns: 1fr;
    }

    .page-back-link {
        display: flex;
        width: calc(100% - 2rem);
        margin: 1rem auto;
        box-sizing: border-box;
    }

    .class-nine-seo-article {
        width: calc(100% - 1rem);
        margin: 2rem auto;
        padding: 1.35rem 1rem;
        border-radius: 15px;
    }

    .class-nine-seo-article h2 {
        font-size: 1.65rem;
    }

    .class-nine-seo-article h3 {
        margin-top: 2.2rem;
        font-size: 1.35rem;
    }

    .class-nine-seo-article p,
    .class-nine-seo-article li {
        font-size: 0.96rem;
    }

    .seo-article-nav {
        display: grid;
        padding: 1rem;
    }

    .seo-info-grid {
        grid-template-columns: 1fr;
    }

    .subject-seo-card {
        padding: 1.15rem;
    }

    .subject-generator-link {
        display: flex;
        justify-content: center;
        width: 100%;
        box-sizing: border-box;
        text-align: center;
    }

    .seo-article-footer {
        padding: 1.5rem 1rem;
    }
}

@media (max-width: 480px) {
    .features-grid {
        grid-template-columns: 1fr;
    }
    
    .feature-text {
        text-align: center;
    }
}