.premium-content-wrapper { width: 100%; max-width: 1000px; margin: 0 auto; display: flex; flex-direction: column; gap: 3rem; padding: 0 1.5rem; }
        .premium-card { width: 100%; background: var(--bg-panel); border-radius: 1.5rem; border: 1px solid var(--card-border); padding: clamp(2rem, 5vw, 3.5rem) clamp(1.25rem, 5vw, 3.5rem); position: relative; overflow: hidden; box-shadow: var(--shadow-glow); z-index: 1; }
        :root.dark .premium-card { background-image: radial-gradient(circle at 85% -10%, rgba(109, 40, 217, 0.25) 0%, transparent 40%), radial-gradient(circle at 0% 110%, rgba(34, 211, 238, 0.15) 0%, transparent 40%), url("data:image/svg+xml,%3Csvg width='1000' height='1000' viewBox='0 0 1000 1000' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M-100,200 Q400,-100 1000,500' fill='none' stroke='rgba(56,189,248,0.08)' stroke-width='1.5'/%3E%3Cpath d='M0,400 C300,100 700,0 1100,400' fill='none' stroke='rgba(167,139,250,0.06)' stroke-width='2'/%3E%3Cpath d='M200,-50 C500,300 800,700 1200,400' fill='none' stroke='rgba(56,189,248,0.04)' stroke-width='1'/%3E%3Ccircle cx='700' cy='150' r='2' fill='rgba(167,139,250,0.5)'/%3E%3Ccircle cx='850' cy='350' r='1.5' fill='rgba(56,189,248,0.6)'/%3E%3Ccircle cx='450' cy='80' r='1' fill='rgba(255,255,255,0.3)'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: top right; background-size: cover; }

        .content-header-area { position: relative; z-index: 2; margin-bottom: 2.5rem; }
        .intro-card .content-header-area { margin-bottom: 1.5rem; }
        .content-label { display: inline-block; font-size: clamp(13px, 2vw, 14px); font-weight: 700; color: var(--accent-cyan); text-transform: uppercase; letter-spacing: 0.12em; margin-bottom: 1rem; position: relative; }
        .content-label::after { content: ''; position: absolute; bottom: -0.4rem; left: 0; width: 1.5rem; height: 2px; background: var(--accent-cyan); border-radius: 2px; }
        .content-header-area h2 { font-size: clamp(28px, 4vw, 36px); font-weight: 800; color: var(--text-main); margin: 0 0 1rem 0; line-height: 1.2; letter-spacing: -0.02em; }

        .rich-text p { font-size: clamp(16px, 2vw, 17px); color: var(--text-muted); margin: 0 0 1.25rem 0; line-height: 1.8; }
        .rich-text p:last-child { margin-bottom: 0; }
        .rich-text a, .collapsible-content p a { color: var(--link-color); text-decoration: underline; text-underline-offset: 3px; font-weight: 500; transition: all 0.2s; }
        .rich-text a:hover, .collapsible-content p a:hover { text-decoration: underline wavy; outline: 2px solid currentColor; outline-offset: 2px; }

        .collapsible-list { display: flex; flex-direction: column; gap: 1rem; position: relative; z-index: 2; }
        .collapsible-item { background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 1rem; overflow: hidden; transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1); position: relative; }
        .collapsible-item:hover { border-color: rgba(34, 211, 238, 0.4); box-shadow: 0 4px 12px rgba(0, 0, 0, 0.05); }
        .collapsible-item[open] { border-color: transparent; background: var(--bg-panel); box-shadow: inset 0 0 0 1px rgba(255, 255, 255, 0.05), var(--shadow-glow); }
        .collapsible-item[open]::after { content: ''; position: absolute; left: -1px; top: 20%; bottom: 20%; width: 3px; background: linear-gradient(to bottom, var(--accent-cyan), var(--accent-violet)); border-radius: 0 4px 4px 0; box-shadow: 2px 0 16px rgba(34, 211, 238, 0.8); animation: pulseLeftGlow 3s infinite alternate; will-change: opacity; }

        .collapsible-summary { padding: clamp(1.25rem, 3vw, 1.5rem) clamp(1rem, 4vw, 1.75rem); cursor: pointer; list-style: none; display: flex; align-items: center; gap: 1.25rem; font-weight: 700; color: var(--text-main); font-size: clamp(17px, 2.5vw, 20px); line-height: 1.4; transition: color 0.3s ease; }
        .collapsible-summary::-webkit-details-marker { display: none; }
        .collapsible-item[open] .collapsible-summary { border-bottom: 1px solid var(--card-border); color: var(--accent-cyan); }
        .collapsible-summary:focus-visible { outline: 2px solid var(--accent-cyan); outline-offset: -2px; border-radius: 1rem; }

        .icon-action { display: flex; align-items: center; justify-content: center; width: 32px; height: 32px; border-radius: 50%; background: rgba(34, 211, 238, 0.1); color: var(--accent-cyan); flex-shrink: 0; transition: all 0.3s ease; }
        .collapsible-item[open] .icon-action { background: rgba(34, 211, 238, 0.2); box-shadow: inset 0 0 8px rgba(34, 211, 238, 0.2); }
        .icon-action svg { width: 16px; height: 16px; stroke-width: 2.5; }
        .collapsible-summary .icon-minus { display: none; }
        .collapsible-item[open] .collapsible-summary .icon-plus { display: none; }
        .collapsible-item[open] .collapsible-summary .icon-minus { display: block; }

        .item-title { flex-grow: 1; }
        .icon-chevron { color: var(--accent-cyan); transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1); display: flex; align-items: center; }
        .icon-chevron svg { width: 20px; height: 20px; stroke-width: 2.5; }
        .collapsible-item[open] .icon-chevron { transform: rotate(180deg); }

        .collapsible-content { padding: clamp(1.25rem, 4vw, 1.5rem) clamp(1rem, 4vw, 1.75rem); color: var(--text-muted); font-size: clamp(16px, 2vw, 17px); line-height: 1.7; display: flex; flex-direction: column; gap: 1rem; }
        .collapsible-content p { margin: 0; font-weight: 400; }

        .callout-box { margin-top: 3rem; background: var(--card-bg); border: 1px solid var(--card-border); border-radius: 1.25rem; padding: clamp(1.5rem, 4vw, 2rem) clamp(1.25rem, 4vw, 2rem); display: flex; align-items: center; justify-content: space-between; gap: 1.5rem; position: relative; z-index: 2; }
        @media (max-width: 640px) { .callout-box { flex-direction: column; text-align: left; align-items: stretch; gap: 1.25rem; } .callout-info { flex-direction: row; align-items: flex-start; gap: 1rem; } .callout-btn { width: 100%; justify-content: center; } }
        .callout-info { display: flex; align-items: center; gap: 1.25rem; }
        .callout-icon { width: 52px; height: 52px; border-radius: 50%; background: rgba(167, 139, 250, 0.1); color: var(--accent-violet); display: flex; align-items: center; justify-content: center; flex-shrink: 0; border: 1px solid rgba(167, 139, 250, 0.2); }
        .callout-icon svg { width: 26px; height: 26px; stroke-width: 1.5; }
        .callout-text h3 { margin: 0 0 0.35rem 0; color: var(--text-main); font-size: clamp(19px, 2.5vw, 22px); font-weight: 700; line-height: 1.2; }
        .callout-text p { margin: 0; color: var(--text-muted); font-size: clamp(16px, 2vw, 17px); line-height: 1.6; max-width: 380px; }
        .callout-btn { background: linear-gradient(135deg, var(--accent-cyan), var(--accent-violet)); color: #ffffff !important; text-decoration: none; padding: 0.875rem 1.75rem; border-radius: 999px; font-weight: 600; font-size: clamp(16px, 2vw, 17px); display: inline-flex; align-items: center; gap: 0.75rem; transition: transform 0.2s ease, box-shadow 0.2s ease; white-space: nowrap; box-shadow: 0 4px 15px rgba(109, 40, 217, 0.3); border: none; cursor: pointer; }
        .callout-btn:hover, .callout-btn:focus-visible { transform: translateY(-2px); box-shadow: 0 8px 25px rgba(109, 40, 217, 0.5); outline: none; }
        .callout-btn:focus-visible { outline: 2px solid var(--accent-cyan); outline-offset: 2px; }
        .callout-btn svg { width: 18px; height: 18px; stroke-width: 2.5; transition: transform 0.3s; }
        .callout-btn:hover svg { transform: translateX(4px); }

        .premium-footer-wrapper { width: 100%; padding: 0 1.5rem; margin: 3rem auto 1.5rem auto; max-width: 1000px; }