/* ============================================================
   what-is-aipo.css — extracted from what-is-aipo.html
   ============================================================ */

:root {
            --brand: #991B2D;
            --brand-dark: #6E1320;
            --brand-tint: #FCEFEF;
            --ink: #1A1A1A;
            --ink-2: #4B4F58;
            --ink-3: #8A8A8A;
            --line: #E8E6E1;
            --line-2: #DCD9D1;
            --paper: #FFFFFF;
            --paper-2: #FAF8F4;
            --paper-3: #F4F1EA;
            --night: #1A1416;
            --night-2: #2A2125;
            --serif: 'Spectral', Georgia, 'Times New Roman', serif;
            --sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
        }

        /* All page styles are scoped under .aipo-page wrapper to avoid bleeding into layouts/main.php navbar/footer. */
        .aipo-page,
        .aipo-page * { box-sizing: border-box; }
        .aipo-page {
            font-family: var(--sans);
            color: var(--ink);
            background: var(--paper);
            line-height: 1.7;
            font-weight: 400;
            -webkit-font-smoothing: antialiased;
            -moz-osx-font-smoothing: grayscale;
        }
        .aipo-page h1, .aipo-page h2, .aipo-page h3, .aipo-page h4, .aipo-page h5, .aipo-page h6,
        .aipo-page p, .aipo-page ul, .aipo-page ol, .aipo-page figure, .aipo-page blockquote { margin: 0; padding: 0; }

        .aipo-page .container {
            max-width: 1180px;
            margin: 0 auto;
            padding: 0 32px;
        }
        .aipo-page .container-narrow {
            max-width: 880px;
            margin: 0 auto;
            padding: 0 32px;
        }

        /* ============ Eyebrow ============ */
        .eyebrow {
            display: inline-flex;
            align-items: center;
            gap: 12px;
            color: var(--brand);
            font-size: 13px;
            font-weight: 500;
            letter-spacing: 0.18em;
            text-transform: uppercase;
            margin-bottom: 28px;
        }
        .eyebrow::before {
            content: '';
            width: 28px;
            height: 1px;
            background: var(--brand);
        }
        .eyebrow.dark { color: rgba(255,255,255,0.6); }
        .eyebrow.dark::before { background: rgba(255,255,255,0.4); }

        /* ============ Hero ============ */
        .hero {
            padding: 100px 0 60px;
            text-align: center;
            position: relative;
        }
        .hero h1 {
            font-family: var(--serif);
            font-size: clamp(36px, 5.6vw, 64px);
            font-weight: 700;
            line-height: 1.18;
            letter-spacing: -0.01em;
            margin-bottom: 28px;
            color: var(--ink);
        }
        .hero h1 em {
            font-style: normal;
            color: var(--brand);
        }
        .hero .lead {
            font-size: clamp(16px, 1.3vw, 19px);
            color: var(--ink-2);
            max-width: 720px;
            margin: 0 auto 24px;
            line-height: 1.75;
        }

        /* ============ Loop diagram ============ */
        .loop-wrap {
            margin: 40px auto 30px;
            max-width: 760px;
            padding: 0 16px;
        }
        .loop-wrap svg {
            width: 100%;
            height: auto;
            display: block;
        }
        .loop-caption {
            font-size: 13px;
            color: var(--ink-3);
            text-align: center;
            font-style: italic;
            margin-top: 4px;
        }

        /* ============ CTAs ============ */
        .cta-row {
            display: flex;
            justify-content: center;
            align-items: center;
            gap: 24px;
            flex-wrap: wrap;
            margin-top: 32px;
        }
        .btn-primary {
            display: inline-flex;
            align-items: center;
            gap: 10px;
            padding: 18px 32px;
            background: var(--brand);
            color: white;
            text-decoration: none;
            font-size: 15px;
            font-weight: 500;
            border-radius: 4px;
            transition: all .25s;
        }
        .btn-primary:hover {
            background: var(--brand-dark);
            transform: translateY(-1px);
        }
        .btn-primary .arrow { transition: transform .25s; }
        .btn-primary:hover .arrow { transform: translateX(4px); }
        .btn-ghost {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            padding: 17px 28px;
            background: transparent;
            color: var(--ink);
            text-decoration: none;
            font-size: 15px;
            font-weight: 500;
            border: 1px solid var(--line-2);
            border-radius: 4px;
            transition: all .25s;
        }
        .btn-ghost:hover {
            border-color: var(--ink);
        }

        /* ============ Section base ============ */
        section.block {
            padding: 100px 0;
            border-top: 1px solid var(--line);
        }
        section.block.alt { background: var(--paper-2); }
        section.block.alt-warm { background: var(--paper-3); }

        h2.section-title {
            font-family: var(--serif);
            font-size: clamp(28px, 3.2vw, 42px);
            font-weight: 700;
            line-height: 1.25;
            letter-spacing: -0.005em;
            color: var(--ink);
            margin-bottom: 18px;
        }
        h2.section-title.dark { color: white; }
        .section-sub {
            font-size: 17px;
            color: var(--ink-2);
            margin-bottom: 48px;
            max-width: 680px;
            line-height: 1.7;
        }

        /* ============ Why AIPO ============ */
        .reason-body p {
            font-size: 17px;
            line-height: 1.85;
            color: var(--ink-2);
            margin-bottom: 22px;
        }
        .reason-body p strong {
            color: var(--ink);
            font-weight: 500;
        }
        .reason-body .pull {
            font-family: var(--serif);
            font-size: 22px;
            line-height: 1.6;
            color: var(--ink);
            font-weight: 500;
            margin: 36px 0;
            padding: 22px 28px;
            border-left: 3px solid var(--brand);
            background: var(--paper-2);
        }

        /* ============ Definition box ============ */
        .definition-card {
            background: var(--paper);
            border: 1px solid var(--line);
            border-top: 3px solid var(--brand);
            padding: 40px 44px;
            margin: 32px 0;
        }
        .definition-card .label {
            font-family: var(--serif);
            font-size: 13px;
            color: var(--brand);
            letter-spacing: 0.16em;
            margin-bottom: 14px;
            font-weight: 500;
            text-transform: uppercase;
        }
        .definition-card .term {
            font-family: var(--serif);
            font-size: 28px;
            font-weight: 700;
            color: var(--ink);
            margin-bottom: 16px;
            line-height: 1.3;
        }
        .definition-card .meaning {
            font-size: 17px;
            line-height: 1.8;
            color: var(--ink-2);
        }

        .acronym-grid {
            display: grid;
            grid-template-columns: repeat(3, 1fr);
            gap: 1px;
            background: var(--line);
            border: 1px solid var(--line);
            margin-top: 32px;
        }
        .acronym-cell {
            background: var(--paper);
            padding: 28px 24px;
        }
        .acronym-cell .letter {
            font-family: var(--serif);
            font-size: 48px;
            font-weight: 900;
            color: var(--brand);
            line-height: 1;
            margin-bottom: 12px;
            display: block;
        }
        .acronym-cell .word {
            font-size: 14px;
            font-weight: 500;
            color: var(--ink);
            margin-bottom: 6px;
            letter-spacing: 0.04em;
        }
        .acronym-cell .word .cn { color: var(--ink-3); margin-left: 6px; font-weight: 400; }
        .acronym-cell .desc {
            font-size: 13.5px;
            color: var(--ink-2);
            line-height: 1.65;
            margin-top: 10px;
        }

        /* ============ Comparison table ============ */
        .versus {
            width: 100%;
            border-collapse: collapse;
        }
        .versus thead th {
            text-align: left;
            padding: 22px 24px;
            font-family: var(--serif);
            font-weight: 700;
            font-size: 18px;
            border-bottom: 2px solid var(--ink);
        }
        .versus thead th:first-child {
            font-family: var(--sans);
            font-weight: 500;
            font-size: 13px;
            color: var(--ink-3);
            letter-spacing: 0.1em;
            text-transform: uppercase;
        }
        .versus thead th:nth-child(2) { color: var(--ink-3); }
        .versus thead th:nth-child(3) { color: var(--brand); }
        .versus tbody td {
            padding: 22px 24px;
            border-bottom: 1px solid var(--line);
            font-size: 15.5px;
            line-height: 1.7;
            vertical-align: top;
        }
        .versus tbody td:first-child {
            font-weight: 500;
            color: var(--ink);
            width: 24%;
        }
        .versus tbody td:nth-child(2) {
            color: var(--ink-3);
            width: 38%;
        }
        .versus tbody td:nth-child(3) {
            color: var(--ink);
            width: 38%;
        }
        .versus-summary {
            margin-top: 36px;
            padding: 26px 30px;
            background: var(--paper);
            border-left: 3px solid var(--brand);
            font-family: var(--serif);
            font-size: 19px;
            color: var(--ink);
            line-height: 1.6;
        }

        /* ============ Five environments ============ */
        .env-list {
            display: flex;
            flex-direction: column;
            gap: 0;
        }
        .env-item {
            display: grid;
            grid-template-columns: 120px 1fr 200px;
            gap: 36px;
            padding: 40px 0;
            border-bottom: 1px solid var(--line);
            align-items: start;
        }
        .env-item:first-child { border-top: 1px solid var(--line); }
        .env-num {
            font-family: var(--serif);
            font-size: 56px;
            font-weight: 900;
            color: var(--brand);
            line-height: 1;
        }
        .env-content h3 {
            font-family: var(--serif);
            font-size: 24px;
            font-weight: 700;
            color: var(--ink);
            margin-bottom: 12px;
        }
        .env-content p {
            font-size: 15.5px;
            line-height: 1.75;
            color: var(--ink-2);
            margin: 0;
        }
        .env-link {
            text-align: right;
        }
        .env-link a {
            display: inline-flex;
            align-items: center;
            gap: 8px;
            color: var(--brand);
            text-decoration: none;
            font-size: 14px;
            font-weight: 500;
            padding: 8px 0;
            border-bottom: 1px solid transparent;
            transition: border-color .2s;
        }
        .env-link a:hover { border-bottom-color: var(--brand); }
        .env-link .arrow { transition: transform .25s; display: inline-block; }
        .env-link a:hover .arrow { transform: translateX(4px); }

        /* ============ Closed loop philosophy ============ */
        .loop-philo {
            background: var(--night);
            color: white;
            padding: 110px 0;
            position: relative;
            overflow: hidden;
        }
        .loop-philo::before {
            content: '';
            position: absolute;
            top: 0; left: 0; right: 0; bottom: 0;
            background-image:
                radial-gradient(circle at 20% 30%, rgba(153,27,45,0.18) 0%, transparent 50%),
                radial-gradient(circle at 80% 70%, rgba(153,27,45,0.12) 0%, transparent 50%);
            pointer-events: none;
        }
        .loop-philo > .container-narrow { position: relative; z-index: 1; }
        .loop-philo .section-sub { color: rgba(255,255,255,0.7); }
        .loop-philo .reason-body p { color: rgba(255,255,255,0.82); }
        .loop-philo .reason-body p strong { color: white; }
        .loop-philo .pull {
            font-family: var(--serif);
            font-size: 22px;
            line-height: 1.6;
            color: white;
            font-weight: 500;
            margin: 36px 0;
            padding: 24px 30px;
            border-left: 3px solid var(--brand);
            background: rgba(255,255,255,0.04);
        }

        /* ============ Origin ============ */
        .origin-body p {
            font-size: 17px;
            line-height: 1.9;
            color: var(--ink-2);
            margin-bottom: 22px;
        }
        .origin-body p:first-letter {
            font-family: var(--serif);
            font-size: 1.3em;
            font-weight: 700;
            color: var(--brand);
        }

        /* ============ Final CTA ============ */
        .final-cta {
            text-align: center;
            padding: 120px 0;
            background: var(--paper-3);
            border-top: 1px solid var(--line);
        }
        .final-cta h2 {
            font-family: var(--serif);
            font-size: clamp(30px, 3.4vw, 44px);
            font-weight: 700;
            line-height: 1.25;
            color: var(--ink);
            margin-bottom: 20px;
        }
        .final-cta p {
            font-size: 17px;
            color: var(--ink-2);
            line-height: 1.7;
            max-width: 600px;
            margin: 0 auto 36px;
        }
        .final-cta .cta-row { justify-content: center; }

        /* ============ Responsive ============ */
        @media (max-width: 880px) {
            .hero { padding: 60px 0 40px; }
            section.block { padding: 70px 0; }
            .acronym-grid { grid-template-columns: 1fr; }
            .versus thead th, .versus tbody td { padding: 14px 12px; font-size: 14px; }
            .versus tbody td:first-child { width: 28%; }
            .env-item {
                grid-template-columns: 60px 1fr;
                gap: 20px;
                padding: 28px 0;
            }
            .env-num { font-size: 40px; }
            .env-link {
                grid-column: 1 / -1;
                text-align: left;
                padding-left: 80px;
                margin-top: -8px;
            }
            .loop-philo { padding: 70px 0; }
            .final-cta { padding: 70px 0; }
            .definition-card { padding: 28px 24px; }
        }