/* Ardyn Design System v4.0 — Trust Infrastructure */
/* Canonical: docs/design/ARDYN_WEBSITE_DESIGN_DOCTRINE.md */
:root {
    /* Backgrounds */
    --bg: #FAFAFA;
    --bg-card: #FFFFFF;
    --bg-hover: #F8FAFC;
    --bg-elevated: #FFFFFF;
    --bg-alt: #F1F5F9;

    /* Text */
    --text: #0F172A;
    --text-secondary: #475569;
    --text-tertiary: #94A3B8;
    --text-muted: #CBD5E1;

    /* Accent — deep navy, not teal */
    --accent: #1E3A5F;
    --accent-dim: rgba(30, 58, 95, 0.06);
    --accent-hover: #15294A;
    --accent-trust: #2563EB;
    --accent-trust-dim: rgba(37, 99, 235, 0.06);

    /* Status */
    --status-valid: #059669;
    --status-warn: #D97706;
    --status-invalid: #DC2626;
    --status-experimental: #6366F1;

    /* Borders */
    --border: #E5E7EB;
    --border-strong: #D1D5DB;

    /* Radii */
    --radius-sm: 6px;
    --radius-md: 10px;
    --radius-lg: 14px;

    /* Typography */
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    font-size: 16px;
    line-height: 1.5;
    color: var(--text);
    background: var(--bg);
}

/* Reset */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

/* Typography */
html { scroll-behavior: smooth; }
body {
    font-family: 'Inter', sans-serif;
    background: var(--bg);
    color: var(--text);
    font-size: 1rem;
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    letter-spacing: -0.01em;
}
h1 {
    font-size: clamp(2.5rem, 5vw, 3.75rem);
    font-weight: 700;
    line-height: 1.08;
    letter-spacing: -0.04em;
    margin-bottom: 24px;
}
h2 {
    font-size: clamp(1.75rem, 3vw, 2.25rem);
    font-weight: 600;
    line-height: 1.18;
    letter-spacing: -0.03em;
    margin-bottom: 18px;
}
h3 {
    font-size: 1.125rem;
    font-weight: 600;
    line-height: 1.35;
    letter-spacing: -0.02em;
}
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }
code {
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85em;
    background: var(--bg-alt);
    padding: 2px 6px;
    border-radius: 4px;
    color: var(--text-secondary);
}

/* Nav */
nav {
    position: fixed; top: 0; left: 0; right: 0; z-index: 100;
    display: flex; align-items: center; justify-content: space-between;
    padding: 16px 40px;
    background: rgba(250, 250, 250, 0.92);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
}
nav .logo { font-weight: 800; font-size: 1.25rem; color: var(--text); letter-spacing: -0.03em; }
nav .nav-links { display: flex; gap: 28px; }
nav .nav-links a { color: var(--text-secondary); font-size: 0.9rem; font-weight: 500; transition: color 0.15s; }
nav .nav-links a:hover { color: var(--text); }
nav .nav-links a.active { color: var(--accent); }
.nav-cta {
    background: var(--accent); color: white;
    padding: 8px 18px; border-radius: var(--radius-sm);
    font-size: 0.85rem; font-weight: 600;
    transition: background 0.15s;
}
.nav-cta:hover { background: var(--accent-hover); color: white; }

/* Hamburger menu (mobile) */
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 4px; }
.nav-toggle span { display: block; width: 22px; height: 2px; background: var(--text); margin: 5px 0; border-radius: 1px; transition: all 0.2s; }

.nav-cta { display: inline-block; }

/* Buttons */
.btn-primary {
    display: inline-block;
    background: var(--accent); color: white;
    padding: 12px 28px; border-radius: var(--radius-sm);
    font-size: 0.9rem; font-weight: 600;
    transition: background 0.15s;
    border: none; cursor: pointer;
}
.btn-primary:hover { background: var(--accent-hover); color: white; }
.btn-secondary {
    display: inline-block;
    background: transparent; color: var(--text-secondary);
    padding: 12px 28px; border-radius: var(--radius-sm);
    font-size: 0.9rem; font-weight: 500;
    border: 1px solid var(--border);
    transition: all 0.15s;
}
.btn-secondary:hover { border-color: var(--text-tertiary); color: var(--text); }
.btn-group { display: flex; gap: 14px; flex-wrap: wrap; }

/* Layout */
.container { max-width: 1040px; margin: 0 auto; padding: 0 40px; }
section { padding: 120px 0; }
.bg-alt { background: var(--bg-alt); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); }

/* Section labels */
.section-label {
    display: block;
    font-size: 0.68rem; text-transform: uppercase;
    letter-spacing: 0.14em; color: var(--text-tertiary);
    margin-bottom: 14px; font-weight: 600;
}
.section-intro {
    color: var(--text-secondary); max-width: 640px;
    margin: 0 auto 48px auto; text-align: center;
    line-height: 1.7; font-size: 1.05rem;
}

/* Cards */
.card {
    background: var(--bg-card); border: 1px solid var(--border);
    border-radius: var(--radius-md); padding: 36px 32px;
}

/* Footer */
footer {
    border-top: 1px solid var(--border); padding: 56px 0;
    text-align: center; background: var(--bg-card);
}
footer .footer-links { display: flex; gap: 28px; justify-content: center; margin-bottom: 18px; flex-wrap: wrap; }
footer .footer-links a { color: var(--text-tertiary); text-decoration: none; font-size: 0.85rem; transition: color 0.2s; }
footer .footer-links a:hover { color: var(--text-secondary); }
footer .footer-copy { color: var(--text-tertiary); font-size: 0.875rem; }

/* Trust Ladder Cards */
.ladder-cards { max-width: 640px; margin: 0 auto; display: flex; flex-direction: column; gap: 0; }
.ladder-card { display: flex; gap: 20px; align-items: flex-start; background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-md); padding: 28px 28px; }
.ladder-step-label { width: 36px; height: 36px; border-radius: 50%; background: var(--accent); color: white; display: flex; align-items: center; justify-content: center; font-size: 0.85rem; font-weight: 700; flex-shrink: 0; margin-top: 2px; }
.ladder-card-body h4 { font-size: 1.05rem; font-weight: 600; color: var(--text); margin-bottom: 6px; }
.ladder-card-body p { font-size: 0.9rem; color: var(--text-secondary); line-height: 1.6; }
.ladder-connector { text-align: center; padding: 4px 0; }
.ladder-connector span { font-size: 1.2rem; color: var(--text-muted); }

/* Responsive */
@media (max-width: 768px) {
    .container { padding: 0 24px; }
    section { padding: 80px 0; }
    nav { padding: 14px 24px; flex-wrap: wrap; }
    nav .nav-links { display: none; width: 100%; flex-direction: column; gap: 0; padding-top: 14px; }
    nav .nav-links.open { display: flex; }
    nav .nav-links a { padding: 10px 0; font-size: 0.95rem; border-bottom: 1px solid var(--border); }
    nav .nav-links a:last-child { border-bottom: none; }
    .nav-toggle { display: block; }
    .nav-cta { display: none; }
    .nav-cta.mobile-show { display: inline-block; margin-top: 12px; }
    .ladder-card { flex-direction: column; gap: 12px; padding: 20px; }
}