/* ═══════════════════════════════════════════
   InviteAI — Core Design System
   ═══════════════════════════════════════════ */

:root {
    /* Palette */
    --bg: #F6F2ED;
    --bg-warm: #EDE7DF;
    --surface: #FFFFFF;
    --surface-raised: #FFFFFF;
    --border: rgba(28, 18, 10, 0.07);
    --border-hover: rgba(28, 18, 10, 0.14);
    --text-primary: #1C120A;
    --text-secondary: #5C4A3A;
    --text-tertiary: #8A7A6C;
    --text-muted: #AEA196;
    --accent: #B85C3C;
    --accent-hover: #9E4D30;
    --accent-soft: rgba(184, 92, 60, 0.07);
    --accent-glow: rgba(184, 92, 60, 0.12);
    --gold: #C4A24E;
    --gold-soft: rgba(196, 162, 78, 0.12);
    --sage: #7B9067;
    --header-bg: #1C120A;
    --header-text: #E8DFD4;

    /* Elevation */
    --shadow-1: 0 1px 2px rgba(28,18,10,0.04);
    --shadow-2: 0 2px 8px rgba(28,18,10,0.06);
    --shadow-3: 0 4px 16px rgba(28,18,10,0.07), 0 1px 3px rgba(28,18,10,0.04);
    --shadow-4: 0 8px 32px rgba(28,18,10,0.08), 0 2px 6px rgba(28,18,10,0.04);
    --shadow-5: 0 16px 48px rgba(28,18,10,0.1), 0 4px 12px rgba(28,18,10,0.05);

    /* Radius */
    --r-xs: 6px;
    --r-sm: 10px;
    --r-md: 14px;
    --r-lg: 20px;

    /* Motion */
    --ease: cubic-bezier(0.4, 0, 0.2, 1);
    --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
    --dur: 0.2s;
    --dur-md: 0.35s;

    /* Type */
    --font-display: 'Cormorant Garamond', Georgia, 'Times New Roman', serif;
    --font-body: 'DM Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

body {
    font-family: var(--font-body);
    color: var(--text-primary);
    background: var(--bg);
    line-height: 1.55;
    min-height: 100vh;
    overflow-x: hidden;
}

/* ── Subtle texture ── */
.texture-overlay {
    position: fixed;
    inset: 0;
    pointer-events: none;
    z-index: 9999;
    opacity: 0.018;
    background-image: url("data:image/svg+xml,%3Csvg width='400' height='400' xmlns='http://www.w3.org/2000/svg'%3E%3Cfilter id='n'%3E%3CfeTurbulence type='fractalNoise' baseFrequency='0.65' numOctaves='4' stitchTiles='stitch'/%3E%3C/filter%3E%3Crect width='100%25' height='100%25' filter='url(%23n)'/%3E%3C/svg%3E");
}

/* ── Typography ── */
h1, h2, h3, h4 {
    font-family: var(--font-display);
    font-weight: 500;
    line-height: 1.15;
    letter-spacing: -0.02em;
    color: var(--text-primary);
}

h2 { font-size: clamp(1.85rem, 4.5vw, 2.75rem); }
h3 { font-size: 1.25rem; color: var(--text-secondary); }
p  { color: var(--text-secondary); }

/* ═══════ HEADER ═══════ */
.site-header {
    background: var(--header-bg);
    height: 56px;
    display: flex;
    align-items: center;
    padding: 0 1.75rem;
    position: sticky;
    top: 0;
    z-index: 100;
    border-bottom: 1px solid rgba(255,255,255,0.05);
}

.header-inner {
    max-width: 1060px;
    width: 100%;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    text-decoration: none;
    color: var(--header-text);
}

.logo-icon { color: var(--accent); flex-shrink: 0; }
.logo-icon svg { width: 32px; height: 32px; }

.logo-text {
    font-family: var(--font-display);
    font-size: 1.35rem;
    font-weight: 600;
    letter-spacing: -0.03em;
    color: var(--header-text);
}

.logo-text em {
    font-style: normal;
    color: var(--accent);
    opacity: 0.9;
}

.tagline {
    font-size: 0.65rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--header-text);
    opacity: 0.35;
    font-weight: 400;
}

/* ═══════ MAIN ═══════ */
.main-content {
    max-width: 920px;
    margin: 0 auto;
    padding: 2rem 2rem 6rem;
}

/* ═══════ BUTTONS ═══════ */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
    height: 42px;
    padding: 0 1.5rem;
    border-radius: var(--r-sm);
    font-family: var(--font-body);
    font-size: 0.84rem;
    font-weight: 500;
    border: none;
    cursor: pointer;
    transition: all var(--dur) var(--ease);
    text-decoration: none;
    white-space: nowrap;
    letter-spacing: 0.01em;
}

.btn-primary {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 1px 3px rgba(184,92,60,0.25), inset 0 1px 0 rgba(255,255,255,0.08);
}

.btn-primary:hover {
    background: var(--accent-hover);
    box-shadow: 0 4px 14px rgba(184,92,60,0.3), inset 0 1px 0 rgba(255,255,255,0.08);
    transform: translateY(-1px);
}

.btn-primary:active {
    transform: translateY(0);
    box-shadow: 0 1px 2px rgba(184,92,60,0.2);
}

.btn-primary:disabled {
    opacity: 0.35;
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

.btn-secondary {
    background: var(--surface);
    color: var(--text-secondary);
    box-shadow: var(--shadow-1), inset 0 0 0 1px var(--border);
}

.btn-secondary:hover {
    box-shadow: var(--shadow-2), inset 0 0 0 1px var(--border-hover);
    color: var(--accent);
}

.btn-arrow {
    font-size: 0.95em;
    transition: transform var(--dur) var(--ease);
    display: inline-block;
}

.btn:hover .btn-arrow { transform: translateX(2px); }
.btn[data-prev]:hover .btn-arrow { transform: translateX(-2px); }

/* ═══════ FOOTER ═══════ */
.site-footer {
    text-align: center;
    padding: 2rem;
    border-top: 1px solid var(--border);
}

.site-footer p {
    font-size: 0.72rem;
    color: var(--text-muted);
}

/* ═══════ RESPONSIVE ═══════ */
@media (max-width: 768px) {
    .site-header { padding: 0 1rem; }
    .header-inner { gap: 0; }
    .tagline { display: none; }
    .main-content { padding: 1.5rem 1rem 4rem; }
}

@media (max-width: 480px) {
    .site-header { height: 48px; }
    .logo-text { font-size: 1.15rem; }
    .logo-icon svg { width: 26px; height: 26px; }
}