:root {
            --bg-primary: #0B1220;
            --bg-secondary: #111C33;
            --bg-card: rgba(255, 255, 255, 0.03);
            --bg-card-hover: rgba(255, 255, 255, 0.06);
            --border-subtle: rgba(255, 255, 255, 0.07);
            --border-strong: rgba(255, 255, 255, 0.14);
            --accent-primary: #00E5CC;
            --accent-primary-dim: rgba(0, 229, 204, 0.14);
            --accent-secondary: #6C5CE7;
            --accent-secondary-dim: rgba(108, 92, 231, 0.16);
            --accent-gold: #FFB300;
            --accent-gold-dim: rgba(255, 179, 0, 0.14);
            --accent-danger: #FF5C7A;
            --accent-danger-dim: rgba(255, 92, 122, 0.14);
            --text-primary: #FFFFFF;
            --text-secondary: rgba(255, 255, 255, 0.72);
            --text-tertiary: rgba(255, 255, 255, 0.45);
            --text-on-accent: #0B1220;
            --font-sans: 'Inter', 'PingFang SC', 'Microsoft YaHei', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
            --font-mono: 'JetBrains Mono', 'SF Mono', 'Fira Code', 'Consolas', monospace;
            --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.28);
            --shadow-glow: 0 0 42px rgba(0, 229, 204, 0.10);
            --shadow-glow-strong: 0 0 72px rgba(0, 229, 204, 0.18);
            --radius-sm: 10px;
            --radius-md: 16px;
            --radius-lg: 24px;
            --radius-xl: 32px;
            --transition-fast: 180ms ease;
            --transition-medium: 320ms ease;
            --transition-slow: 520ms cubic-bezier(0.22, 1, 0.36, 1);
            --section-pad: 96px 0;
            --shell-max: 1200px;
            --shell-pad: 0 40px;
        }
        *,
        *::before,
        *::after { margin: 0; padding: 0; box-sizing: border-box; }
        html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; -moz-osx-font-smoothing: grayscale; background: var(--bg-primary); }
        body { font-family: var(--font-sans); font-size: 16px; line-height: 1.7; color: var(--text-secondary); background: var(--bg-primary); overflow-x: hidden; min-height: 100vh; }
        img { max-width: 100%; height: auto; display: block; }
        a { color: var(--accent-primary); text-decoration: none; transition: color var(--transition-fast); }
        a:hover { color: #33F5E0; }
        h1, h2, h3, h4, h5, h6 { color: var(--text-primary); font-weight: 700; line-height: 1.25; letter-spacing: -0.02em; }
        h1 { font-size: clamp(2.6rem, 6vw, 4.8rem); font-weight: 800; letter-spacing: -0.04em; }
        h2 { font-size: clamp(1.8rem, 3.5vw, 2.8rem); letter-spacing: -0.03em; }
        h3 { font-size: clamp(1.25rem, 2vw, 1.6rem); letter-spacing: -0.02em; }
        ul, ol { list-style: none; }
        .section-shell { max-width: var(--shell-max); margin: 0 auto; padding: var(--shell-pad); }

        /* Header */
        .site-header { position: sticky; top: 0; z-index: 1000; background: rgba(11, 18, 32, 0.82); backdrop-filter: blur(22px); -webkit-backdrop-filter: blur(22px); border-bottom: 1px solid var(--border-subtle); transition: background var(--transition-medium); }
        .site-header.scrolled { background: rgba(11, 18, 32, 0.95); border-bottom-color: var(--border-strong); }
        .header-inner { display: flex; align-items: center; justify-content: space-between; height: 72px; gap: 24px; }
        .brand { display: flex; align-items: center; gap: 10px; font-size: 1.35rem; font-weight: 800; color: var(--text-primary); letter-spacing: -0.02em; flex-shrink: 0; }
        .brand svg { width: 38px; height: 38px; border-radius: var(--radius-sm); }
        .brand:hover { color: var(--accent-primary); }
        .nav-links { display: flex; align-items: center; gap: 4px; flex-wrap: wrap; justify-content: center; }
        .nav-links a { padding: 8px 14px; border-radius: 8px; font-size: 0.88rem; font-weight: 500; color: var(--text-tertiary); transition: all var(--transition-fast); white-space: nowrap; }
        .nav-links a:hover { color: var(--text-primary); background: var(--bg-card-hover); }
        .nav-links a.active { color: var(--accent-primary); background: var(--accent-primary-dim); font-weight: 600; }
        .header-action { padding: 9px 20px; border-radius: 10px; font-weight: 600; font-size: 0.88rem; background: var(--accent-primary); color: var(--text-on-accent) !important; flex-shrink: 0; transition: all var(--transition-fast); border: none; cursor: pointer; }
        .header-action:hover { background: #33F5E0; transform: translateY(-1px); box-shadow: 0 4px 20px rgba(0,229,204,0.3); }
        .nav-toggle { display: none; background: none; border: 1px solid var(--border-strong); border-radius: 8px; padding: 8px 12px; cursor: pointer; color: var(--text-primary); font-size: 1.2rem; line-height: 1; }

        /* Security Hero */
        .security-hero { padding: 100px 0 80px; background: radial-gradient(ellipse 55% 50% at 30% 10%, rgba(0,229,204,0.10) 0%, transparent 70%), radial-gradient(ellipse 35% 35% at 85% 25%, rgba(108,92,231,0.08) 0%, transparent 60%), var(--bg-primary); border-bottom: 1px solid var(--border-subtle); position: relative; overflow: hidden; }
        .security-hero::before { content: ''; position: absolute; inset: 0; background-image: linear-gradient(rgba(255,255,255,0.015) 1px, transparent 1px), linear-gradient(90deg, rgba(255,255,255,0.015) 1px, transparent 1px); background-size: 72px 72px; pointer-events: none; mask-image: radial-gradient(ellipse 70% 60% at 50% 40%, black 30%, transparent 70%); -webkit-mask-image: radial-gradient(ellipse 70% 60% at 50% 40%, black 30%, transparent 70%); }
        .security-hero-inner { position: relative; z-index: 1; display: grid; grid-template-columns: 1.1fr 0.9fr; gap: 48px; align-items: center; }
        .security-hero-copy .eyebrow { font-family: var(--font-mono); font-size: 0.78rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--accent-primary); margin-bottom: 16px; display: flex; align-items: center; gap: 10px; }
        .security-hero-copy .eyebrow::before { content: ''; width: 32px; height: 2px; background: var(--accent-primary); border-radius: 2px; }
        .security-hero-copy h1 { margin-bottom: 20px; background: linear-gradient(135deg, #FFFFFF 20%, #B0E8E0 60%, #00E5CC 100%); -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent; color: transparent; }
        .security-hero-copy>p:not(.eyebrow) { font-size: 1.12rem; line-height: 1.85; max-width: 540px; margin-bottom: 36px; color: var(--text-secondary); }
        .hero-actions { display: flex; flex-wrap: wrap; gap: 14px; }
        .primary-button { display: inline-flex; align-items: center; gap: 8px; padding: 14px 32px; border-radius: 12px; font-weight: 700; font-size: 1rem; background: var(--accent-primary); color: var(--text-on-accent); transition: all var(--transition-medium); border: none; cursor: pointer; letter-spacing: 0.01em; }
        .primary-button:hover { background: #33F5E0; transform: translateY(-2px); box-shadow: 0 8px 32px rgba(0,229,204,0.35); color: var(--text-on-accent); }
        .outline-button { display: inline-flex; align-items: center; gap: 8px; padding: 14px 28px; border-radius: 12px; font-weight: 600; font-size: 1rem; background: transparent; color: var(--text-primary); border: 1px solid var(--border-strong); transition: all var(--transition-medium); cursor: pointer; }
        .outline-button:hover { border-color: var(--accent-primary); color: var(--accent-primary); background: var(--accent-primary-dim); }
        .security-hero-visual { display: flex; justify-content: center; align-items: center; background: var(--bg-card); border-radius: var(--radius-xl); border: 1px solid var(--border-subtle); box-shadow: var(--shadow-card); backdrop-filter: blur(12px); padding: 40px; min-height: 350px; }
        .encryption-visual { text-align: center; width: 100%; }
        .encryption-visual .visual-badge { font-family: var(--font-mono); font-size: 0.85rem; letter-spacing: 0.12em; color: var(--accent-primary); margin-bottom: 20px; }
        .key-icon { font-size: 4rem; margin-bottom: 16px; }
        .key-details { display: flex; justify-content: center; gap: 24px; flex-wrap: wrap; }
        .key-details .detail-item { text-align: center; }
        .key-details .detail-label { font-family: var(--font-mono); font-size: 0.7rem; letter-spacing: 0.1em; text-transform: uppercase; color: var(--text-tertiary); }
        .key-details .detail-value { font-size: 1.6rem; font-weight: 800; color: var(--text-primary); }

        /* Section Headings */
        .section-heading { text-align: center; margin-bottom: 56px; }
        .section-heading .eyebrow { font-family: var(--font-mono); font-size: 0.78rem; letter-spacing: 0.18em; text-transform: uppercase; color: var(--accent-gold); margin-bottom: 10px; }
        .section-heading h2 { margin-bottom: 14px; }
        .section-heading p { max-width: 620px; margin: 0 auto; color: var(--text-secondary); }

        /* AES Encryption Details */
        .aes-details { padding: var(--section-pad); background: var(--bg-primary); }
        .aes-grid { display: grid; grid-template-columns: repeat(3, 1fr); gap: 20px; }
        .aes-card { padding: 32px 24px; background: var(--bg-card); border-radius: var(--radius-lg); border: 1px solid var(--border-subtle); transition: all var(--transition-medium); position: relative; overflow: hidden; }
        .aes-card::after { content: ''; position: absolute; top: 0; left: 0; right: 0; height: 3px; background: linear-gradient(90deg, var(--accent-primary), var(--accent-secondary)); transform: scaleX(0); transform-origin: left; transition: transform var(--transition-medium); }
        .aes-card:hover::after { transform: scaleX(1); }
        .aes-card:hover { border-color: var(--border-strong); background: var(--bg-card-hover); transform: translateY(-6px); }
        .aes-icon { font-size: 2.2rem; margin-bottom: 16px; }
        .aes-card h3 { font-size: 1.3rem; margin-bottom: 10px; }
        .aes-card p { font-size: 0.95rem; color: var(--text-tertiary); }

        /* Protocol Comparison */
        .protocol-comparison { padding: var(--section-pad); background: var(--bg-secondary); border-top: 1px solid var(--border-subtle); border-bottom: 1px solid var(--border-subtle); }
        .protocol-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 24px; max-width: 900px; margin: 0 auto; }
        .protocol-card { padding: 32px 28px; background: var(--bg-card); border-radius: var(--radius-lg); border: 1px solid var(--border-subtle); transition: all var(--transition-medium); }
        .protocol-card:hover { border-color: var(--accent-primary); background: var(--bg-card-hover); transform: translateY(-4px); }
        .protocol-card .protocol-name { font-family: var(--font-mono); font-size: 1.2rem; letter-spacing: 0.08em; color: var(--accent-primary); margin-bottom: 12px; }
        .protocol-card .protocol-desc { font-size: 0.95rem; color: var(--text-secondary); margin-bottom: 16px; }
        .protocol-features { display: flex; flex-direction: column; gap: 8px; }
        .protocol-feature { display: flex; align-items: center; gap: 8px; font-size: 0.9rem; color: var(--text-tertiary); }
        .protocol-feature::before { content: '✓'; color: var(--accent-primary); font-weight: 700; }

        /* Security Features Grid */
        .security-features { padding: var(--section-pad); background: var(--bg-primary); }
        .feature-grid { display: grid; grid-template-columns: repeat(4, 1fr); gap: 20px; }
        .feature-card { padding: 24px 20px; background: var(--bg-card); border-radius: var(--radius-md); border: 1px solid var(--border-subtle); transition: all var(--transition-medium); }
        .feature-card:hover { border-color: var(--accent-secondary); background: var(--bg-card-hover); transform: translateY(-4px); }
        .feature-icon { font-size: 2rem; margin-bottom: 12px; }
        .feature-card h4 { font-size: 1.05rem; margin-bottom: 8px; }
        .feature-card p { font-size: 0.88rem; color: var(--text-tertiary); }

        /* Transparency / Open Source */
        .open-source { padding: var(--section-pad); background: var(--bg-secondary); border-top: 1px solid var(--border-subtle); border-bottom: 1px solid var(--border-subtle); }
        .open-source-content { display: grid; grid-template-columns: 1fr 1fr; gap: 40px; align-items: center; }
        .open-source-copy h3 { font-size: 1.8rem; margin-bottom: 16px; }
        .open-source-copy p { color: var(--text-secondary); margin-bottom: 16px; }
        .open-source-copy .highlight-stat { font-family: var(--font-mono); font-size: 3rem; font-weight: 800; color: var(--accent-primary); }
        .open-source-visual { background: var(--bg-card); border-radius: var(--radius-xl); padding: 32px; border: 1px solid var(--border-subtle); text-align: center; }
        .code-snippet { background: rgba(0,0,0,0.3); padding: 16px; border-radius: var(--radius-sm); font-family: var(--font-mono); font-size: 0.8rem; color: var(--text-tertiary); text-align: left; overflow-x: auto; }

        /* Security Badge Strip */
        .security-badge-strip { padding: 72px 0; background: var(--bg-primary); border-bottom: 1px solid var(--border-subtle); }
        .badge-grid { display: grid; grid-template-columns: repeat(5, 1fr); gap: 16px; text-align: center; }
        .badge-item { padding: 20px 12px; background: var(--bg-card); border-radius: var(--radius-sm); border: 1px solid var(--border-subtle); transition: all var(--transition-fast); }
        .badge-item:hover { border-color: var(--accent-gold); background: var(--bg-card-hover); }
        .badge-icon { font-size: 1.8rem; margin-bottom: 8px; }
        .badge-label { font-size: 0.8rem; color: var(--text-tertiary); }
        .badge-value { font-size: 1.1rem; font-weight: 700; color: var(--text-primary); }

        /* FAQ */
        .faq-section { padding: var(--section-pad); background: var(--bg-secondary); border-top: 1px solid var(--border-subtle); border-bottom: 1px solid var(--border-subtle); }
        .faq-list { max-width: 800px; margin: 0 auto; }
        .faq-item { padding: 24px 0; border-bottom: 1px solid var(--border-subtle); }
        .faq-item:last-child { border-bottom: none; }
        .faq-question { font-size: 1.15rem; font-weight: 600; color: var(--text-primary); margin-bottom: 10px; cursor: pointer; display: flex; justify-content: space-between; align-items: center; }
        .faq-question::after { content: '+'; font-size: 1.6rem; color: var(--accent-primary); transition: transform var(--transition-fast); }
        .faq-question.active::after { transform: rotate(45deg); }
        .faq-answer { font-size: 0.95rem; color: var(--text-secondary); max-height: 0; overflow: hidden; transition: max-height 0.4s ease; }

        /* CTA */
        .cta-section { padding: 80px 0; background: var(--bg-primary); text-align: center; }
        .cta-section h2 { margin-bottom: 16px; }
        .cta-section p { color: var(--text-secondary); max-width: 560px; margin: 0 auto 32px; }
        .cta-actions { display: flex; gap: 16px; justify-content: center; flex-wrap: wrap; }

        /* Footer */
        .site-footer { padding: 40px 0; background: var(--bg-secondary); border-top: 1px solid var(--border-subtle); }
        .footer-inner { display: flex; align-items: center; justify-content: space-between; gap: 24px; flex-wrap: wrap; }
        .footer-inner p { font-size: 0.85rem; color: var(--text-tertiary); }

        /* Reveal */
        .reveal { opacity: 0; transform: translateY(24px); transition: opacity 0.7s cubic-bezier(0.22, 1, 0.36, 1), transform 0.7s cubic-bezier(0.22, 1, 0.36, 1); }
        .reveal.visible { opacity: 1; transform: translateY(0); }

        /* Responsive */
        @media (max-width: 1024px) {
            .security-hero-inner { grid-template-columns: 1fr; gap: 36px; }
            .aes-grid { grid-template-columns: 1fr 1fr; }
            .protocol-grid { grid-template-columns: 1fr; }
            .feature-grid { grid-template-columns: 1fr 1fr; }
            .open-source-content { grid-template-columns: 1fr; }
            .badge-grid { grid-template-columns: repeat(3, 1fr); }
        }
        @media (max-width: 768px) {
            :root { --shell-pad: 0 20px; --section-pad: 64px 0; }
            .nav-links { display: none; position: absolute; top: 72px; left: 0; right: 0; background: rgba(11,18,32,0.96); backdrop-filter: blur(22px); flex-direction: column; padding: 16px 20px; border-bottom: 1px solid var(--border-subtle); }
            .nav-links.open { display: flex; }
            .nav-toggle { display: block; }
            .header-action { display: none; }
            .aes-grid { grid-template-columns: 1fr; }
            .feature-grid { grid-template-columns: 1fr; }
            .badge-grid { grid-template-columns: repeat(2, 1fr); }
        }