body {
  margin: 0;
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: radial-gradient(circle at center, #0f183d, #010414);
  color: #e0e0e0;
  scroll-behavior: smooth;
}

header {
  background: rgba(10, 16, 43, 0.96);
  padding: 1rem 2rem;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border-bottom: 1px solid #1f2b63;
  position: sticky;
  top: 0;
  z-index: 50;
}
.logo { display: flex; align-items: center; }
.logo img { width: 42px; margin-right: 12px; }
.logo h1 { font-size: 1.4rem; color: #00bfff; margin: 0; }
nav ul { list-style: none; display: flex; gap: 1.5rem; margin: 0; padding: 0; }
nav a { color: #a5b4fc; text-decoration: none; font-weight: 500; transition: color 0.2s; }
nav a:hover { color: #ffcc00; }

section { padding: 4rem 2rem; max-width: 1150px; margin: 0 auto; text-align: center; }

/* Hero Styles */
#hero { padding: 6rem 2rem; }
.tagline { font-size: 2.5rem; font-weight: 800; color: #ffcc00; margin: 0.5rem 0; }
.hero-description { font-size: 1.15rem; max-width: 750px; margin: 0 auto 2rem; color: #cbd5e1; line-height: 1.6; }
.hero-actions { display: flex; justify-content: center; gap: 1.2rem; margin-bottom: 2.5rem; }
.hero-bullets { display: inline-flex; flex-wrap: wrap; justify-content: center; gap: 1.5rem; list-style: none; padding: 0; color: #00bfff; font-weight: 600; }

button, .cta-btn {
  background: #00bfff; color: #000; border: none; padding: 0.8rem 1.8rem;
  border-radius: 30px; font-weight: bold; cursor: pointer; transition: all 0.2s ease;
}
button:hover, .cta-btn:hover { background: #ffcc00; transform: translateY(-2px); box-shadow: 0 5px 15px rgba(0, 191, 255, 0.3); }
.btn-secondary { border: 2px solid #00bfff; color: #00bfff; padding: 0.7rem 1.6rem; border-radius: 30px; text-decoration: none; font-weight: bold; transition: all 0.2s; }
.btn-secondary:hover { background: rgba(0, 191, 255, 0.1); color: #ffcc00; border-color: #ffcc00; }

.section-subtitle { font-size: 1.2rem; color: #94a3b8; margin-bottom: 2rem; }
.checklist-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; margin-top: 1rem; }
.check-item { background: rgba(255,255,255,0.03); padding: 0.9rem; border-radius: 8px; border-left: 4px solid #00bfff; text-align: left; font-size: 0.95rem; }

/* Dashboard Panel Settings */
.features-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(300px, 1fr)); gap: 1.5rem; margin-top: 2rem; }
.panel { background: rgba(255,255,255,0.04); border: 1px solid rgba(0, 191, 255, 0.15); padding: 1.5rem; border-radius: 12px; cursor: pointer; transition: all 0.25s ease; text-align: left; }
.panel h4 { margin: 0 0 0.5rem; font-size: 1.3rem; color: #00bfff; }
.panel p { margin: 0; font-size: 0.9rem; color: #94a3b8; line-height: 1.5; }
.panel:hover { background: rgba(0, 191, 255, 0.08); border-color: #00bfff; transform: translateY(-3px); }

/* Core Calculator Platform Viewport layouts */
.calc-container { display: flex; justify-content: center; gap: 2rem; flex-wrap: wrap; margin-top: 1.5rem; }
.main-calc { background: #0b0f26; border: 1px solid #1f2b63; border-radius: 20px; padding: 1.5rem; width: 330px; box-shadow: 0 20px 40px rgba(0,0,0,0.6); }
#display { width: 100%; height: 55px; font-size: 1.9rem; text-align: right; margin-bottom: 1.2rem; border: none; background: #040614; color: #00bfff; border-radius: 10px; padding: 0 14px; box-sizing: border-box; }
.buttons { display: grid; grid-template-columns: repeat(4, 1fr); gap: 10px; }
.buttons button { height: 50px; font-size: 1.25rem; border-radius: 8px; background: rgba(255,255,255,0.05); color: #fff; cursor: pointer; border: none; }
.buttons button:hover { background: rgba(255,255,255,0.14); }
.sci-buttons { grid-template-columns: repeat(4, 1fr); margin-bottom: 12px; border-bottom: 1px solid rgba(255,255,255,0.08); padding-bottom: 12px; }
.sci-buttons button { background: rgba(0, 191, 255, 0.07); color: #00bfff; font-size: 0.95rem; }
#equals { background: #ffcc00; color: #000; font-weight: bold; }
#clear { color: #ef4444; font-weight: bold; }

/* Sidebar Expansion Framework panels */
.side-panels { min-width: 320px; max-width: 360px; flex: 1; }
.panel-content { background: rgba(255,255,255,0.04); border: 1px solid #1f2b63; border-radius: 20px; padding: 1.5rem; text-align: left; box-shadow: 0 10px 25px rgba(0,0,0,0.3); }
.panel-content h4 { margin: 0 0 1.2rem; color: #00bfff; text-align: center; font-size: 1.35rem; border-bottom: 1px dashed rgba(0,191,255,0.2); padding-bottom: 0.5rem; }
.panel-content input, .panel-content select { width: 100%; padding: 0.75rem; margin-bottom: 0.9rem; border-radius: 8px; border: 1px solid rgba(255,255,255,0.1); background: #040614; color: white; box-sizing: border-box; font-size: 1rem; }
.panel-content button { width: 100%; margin-top: 0.4rem; }
.panel-row-btns { display: flex; gap: 0.6rem; }
.result-box { background: rgba(0,0,0,0.4); border-radius: 8px; padding: 1rem; margin-top: 1.2rem; border-left: 4px solid #ffcc00; font-size: 0.95rem; line-height: 1.5; color: #e2e8f0; }
.hidden-panel { display: none !important; }
.selector-row { display: flex; align-items: center; justify-content: space-between; gap: 0.5rem; margin-bottom: 0.5rem; }
.selector-row select { margin: 0; }

/* Audience Target Grids */
.audience-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); gap: 1.5rem; margin-top: 2rem; }
.card { background: linear-gradient(145deg, rgba(255,255,255,0.03), rgba(255,255,255,0.01)); border: 1px solid rgba(255,255,255,0.05); padding: 1.6rem; border-radius: 12px; text-align: left; }
.card h5 { margin: 0 0 0.6rem; font-size: 1.25rem; color: #ffcc00; }
.card p { margin: 0; font-size: 0.95rem; color: #94a3b8; line-height: 1.5; }

.highlights-container { display: flex; flex-wrap: wrap; justify-content: center; gap: 1.5rem; margin-top: 1.5rem; font-weight: 600; color: #00bfff; font-size: 1.05rem; }

/* Social Proofing Blocks */
.testimonial-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); gap: 1.5rem; margin-top: 2rem; }
blockquote { background: rgba(0,0,0,0.25); border: 1px dashed rgba(0,191,255,0.25); padding: 1.6rem; border-radius: 12px; font-style: italic; margin: 0; line-height: 1.6; color: #cbd5e1; text-align: left; }

/* Accordion FAQs Component */
.faq-container { max-width: 800px; margin: 2rem auto 0; text-align: left; }
.faq-item { border-bottom: 1px solid #1f2b63; }
.faq-question { padding: 1.1rem 0; font-weight: 600; cursor: pointer; display: flex; justify-content: space-between; color: #00bfff; font-size: 1.1rem; }
.faq-question:hover { color: #ffcc00; }
.faq-answer { max-height: 0; overflow: hidden; transition: max-height 0.3s ease-out; color: #94a3b8; }
.faq-answer p { padding-bottom: 1.1rem; margin: 0; line-height: 1.6; }

#download .specs-bar { font-weight: 700; color: #ffcc00; letter-spacing: 2px; margin-bottom: 2rem; font-size: 1.1rem; }
.beyond-limits { font-style: italic; margin-top: 2.5rem; color: #475569; font-weight: 500; }

/* Global Hidden Modifier Utility Rule */
.hidden { display: none !important; }

/* Modern Floating Overlay Modal Execution fixes structural overlay failures */
.floating-btn { position: fixed; bottom: 20px; right: 20px; background: #00bfff; color: #000; border: none; padding: 0.8rem 1.4rem; border-radius: 50px; cursor: pointer; box-shadow: 0 4px 20px rgba(0,191,255,0.4); z-index: 100; font-weight: bold; }
.modal { position: fixed; top: 0; left: 0; width: 100%; height: 100%; background: rgba(0,0,0,0.82); display: flex; justify-content: center; align-items: center; z-index: 200; }
.modal-content { background: #090d22; border: 1px solid #1f2b63; padding: 2.2rem; border-radius: 16px; width: 90%; max-width: 440px; position: relative; box-sizing: border-box; }
.close { position: absolute; top: 14px; right: 20px; font-size: 2.2rem; cursor: pointer; color: #64748b; line-height: 1; transition: color 0.2s; }
.close:hover { color: #ffffff; }

#historyList { list-style: none; padding: 0; max-height: 220px; overflow-y: auto; text-align: left; margin: 1.5rem 0; background: rgba(0,0,0,0.4); border-radius: 8px; border: 1px solid rgba(255,255,255,0.05); }
#historyList li { padding: 0.85rem; border-bottom: 1px solid rgba(255,255,255,0.05); display: flex; justify-content: space-between; align-items: center; font-size: 0.9rem; word-break: break-all; color: #e2e8f0; }
#historyList li.empty-history { color: #475569; justify-content: center; font-style: italic; border: none; padding: 1.5rem; }
.copy-btn { padding: 0.35rem 0.7rem; font-size: 0.75rem; background: #1f2b63; border: none; color: #00bfff; border-radius: 4px; cursor: pointer; font-weight: 600; flex-shrink: 0; margin-left: 10px; }
.copy-btn:hover { background: #00bfff; color: #000; }
.clear-btn { width: 100%; background: #ef4444; color: white; border-radius: 8px; padding: 0.7rem; font-weight: bold; }
.clear-btn:hover { background: #dc2626; transform: none; }

footer { text-align: center; padding: 1.5rem; background: #02030d; color: #475569; font-size: 0.9rem; border-top: 1px solid #0f183d; }

@media (max-width: 768px) {
  nav ul { display: none; }
  .calc-container { flex-direction: column; align-items: center; }
  .side-panels { width: 100%; max-width: 330px; }
}