/* ──────────────────────────────────────────────────────────────────────
   Invoice Tracker — Landing Page Global Styles
   Dark theme, system fonts, CSS-only animations.
   Zero JavaScript shipped for styling.
   ────────────────────────────────────────────────────────────────────── */

:root {
    /* Colors */
    --bg:          #0e0f1a;
    --bg-card:     #151625;
    --bg-elevated: #1c1d30;
    --border:      rgba(255, 255, 255, 0.08);
    --border-hover:rgba(255, 255, 255, 0.15);

    --text:        #e5e7f0;
    --text-dim:    #b8bccc;
    --text-muted:  #6b7084;

    --accent:      #4a9eff;
    --accent-glow: rgba(74, 158, 255, 0.15);
    --accent-hover:#3a8eef;

    --green:       #4aff7a;
    --green-dim:   rgba(74, 255, 122, 0.1);
    --amber:       #f0b90b;
    --red:         #ff6b6b;

    /* Typography */
    --font:        'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, sans-serif;
    --font-mono:   'JetBrains Mono', 'Fira Code', monospace;

    /* Spacing */
    --space-xs:    0.25rem;
    --space-sm:    0.5rem;
    --space-md:    1rem;
    --space-lg:    2rem;
    --space-xl:    4rem;
    --space-2xl:   6rem;

    /* Layout */
    --max-w:       1140px;
    --radius:      12px;
    --radius-sm:   8px;
    --radius-pill: 100px;
}

/* ── Reset ─────────────────────────────────────────────────────────── */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; -webkit-font-smoothing: antialiased; }
body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}
img, svg { display: block; max-width: 100%; }
a { color: var(--accent); text-decoration: none; transition: color 0.15s; }
a:hover { color: var(--accent-hover); }

/* ── Container ─────────────────────────────────────────────────────── */
.container {
    max-width: var(--max-w);
    margin: 0 auto;
    padding: 0 1.5rem;
}

/* ── Section ───────────────────────────────────────────────────────── */
.section {
    padding: var(--space-2xl) 0;
}
.section-title {
    font-size: 2.2rem;
    font-weight: 700;
    letter-spacing: -0.02em;
    text-align: center;
    margin-bottom: 0.5rem;
}
.section-sub {
    color: var(--text-dim);
    text-align: center;
    max-width: 560px;
    margin: 0 auto var(--space-xl);
    font-size: 1.05rem;
    line-height: 1.65;
}

/* ── Buttons ───────────────────────────────────────────────────────── */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.85rem 1.8rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 0.95rem;
    border: none;
    cursor: pointer;
    transition: transform 0.12s, box-shadow 0.2s, background 0.15s;
    text-decoration: none;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary {
    background: var(--accent);
    color: white;
    box-shadow: 0 4px 14px rgba(74, 158, 255, 0.3);
}
.btn-primary:hover {
    background: var(--accent-hover);
    box-shadow: 0 6px 20px rgba(74, 158, 255, 0.4);
    color: white;
}
.btn-secondary {
    background: transparent;
    color: var(--text);
    border: 1px solid var(--border-hover);
}
.btn-secondary:hover {
    background: var(--bg-elevated);
    border-color: var(--accent);
    color: var(--accent);
}

/* ── Cards ─────────────────────────────────────────────────────────── */
.card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.8rem;
    transition: border-color 0.2s, transform 0.2s;
}
.card:hover {
    border-color: var(--border-hover);
    transform: translateY(-2px);
}
.card-highlight {
    border-color: var(--accent);
    background: linear-gradient(135deg, var(--bg-card) 0%, rgba(74, 158, 255, 0.04) 100%);
}

/* ── Badge / Pill ──────────────────────────────────────────────────── */
.pill {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    padding: 0.4rem 1rem;
    border-radius: var(--radius-pill);
    background: var(--accent-glow);
    color: var(--accent);
    font-size: 0.85rem;
    font-weight: 500;
}
.badge {
    display: inline-block;
    padding: 0.15rem 0.6rem;
    border-radius: 4px;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.badge-accent {
    background: var(--accent);
    color: white;
}
.badge-green {
    background: var(--green-dim);
    color: var(--green);
}

/* ── Grid utilities ────────────────────────────────────────────────── */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 1.5rem;
}
.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}
.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 1.2rem;
}
@media (max-width: 900px) {
    .grid-3 { grid-template-columns: 1fr; }
    .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 640px) {
    .grid-2, .grid-4 { grid-template-columns: 1fr; }
    .section-title { font-size: 1.7rem; }
    .section { padding: var(--space-xl) 0; }
}

/* ── Fade-in on scroll (CSS-only via IntersectionObserver polyfill) ── */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ── Accent line ───────────────────────────────────────────────────── */
.accent-line {
    width: 60px;
    height: 3px;
    background: var(--accent);
    border-radius: 2px;
    margin: 0 auto 1.5rem;
}

/* ── FAQ accordion (CSS-only via details/summary) ──────────────────── */
.faq-item {
    border-bottom: 1px solid var(--border);
}
.faq-item summary {
    list-style: none;
    cursor: pointer;
    padding: 1.2rem 0;
    font-size: 1.05rem;
    font-weight: 600;
    display: flex;
    justify-content: space-between;
    align-items: center;
    color: var(--text);
    transition: color 0.15s;
}
.faq-item summary:hover { color: var(--accent); }
.faq-item summary::after {
    content: '+';
    font-size: 1.4rem;
    color: var(--text-muted);
    transition: transform 0.2s;
}
.faq-item[open] summary::after {
    transform: rotate(45deg);
    color: var(--accent);
}
.faq-item .faq-answer {
    padding: 0 0 1.2rem;
    color: var(--text-dim);
    line-height: 1.65;
    font-size: 0.95rem;
}