/* ============================================
   DevOps Tool Credit Cost Predictor
   impeccable design system — zero-decoration minimalism
   ============================================ */

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

:root {
  --ink: #000000;
  --canvas: #ffffff;
  --signal: #0052cc;
  --signal-light: #e8f0fe;
  --border: #e5e5e5;
  --bg-subtle: #fafafa;
  --text-secondary: #4a4a4a;
  --radius: 4px;
  --space-1: 4px;
  --space-2: 8px;
  --space-3: 16px;
  --space-4: 24px;
  --space-5: 32px;
  --space-6: 48px;
  --space-7: 64px;
  --font-sans: 'Pretendard', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'SF Mono', 'Fira Code', 'Menlo', monospace;
  --transition: 200ms ease;
}

html { scroll-behavior: smooth; }

body {
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--ink);
  background: var(--canvas);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

img { max-width: 100%; height: auto; display: block; }
a { color: var(--signal); text-decoration: none; }
a:hover { text-decoration: underline; }

.container {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 var(--space-4);
}

/* --- Animations --- */
@keyframes fadeUp {
  from { opacity: 0; transform: translateY(24px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideInLeft {
  from { opacity: 0; transform: translateX(-40px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes slideInRight {
  from { opacity: 0; transform: translateX(40px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes countUp {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

.animate-fade-up {
  animation: fadeUp 0.6s ease forwards;
  opacity: 0;
}

/* --- Header --- */
.header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: rgba(255,255,255,0.96);
  border-bottom: 1px solid var(--border);
  backdrop-filter: blur(8px);
}

.nav {
  max-width: 1120px;
  margin: 0 auto;
  padding: 0 var(--space-4);
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-brand {
  font-weight: 700;
  font-size: 15px;
  letter-spacing: -0.02em;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.nav-links a {
  color: var(--text-secondary);
  font-size: 14px;
  transition: color var(--transition);
  padding: 4px 0;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.nav-links a:hover { color: var(--ink); text-decoration: none; }

.nav-links a.nav-cta {
  display: inline-flex;
  align-items: center;
  padding: 10px 16px;
  background: var(--ink);
  color: var(--canvas);
  border-radius: var(--radius);
  font-size: 14px;
  font-weight: 700;
  transition: background var(--transition);
  min-height: 44px;
}

.nav-links a.nav-cta:hover { background: #222; text-decoration: none; }

/* --- Hero --- */
.hero {
  padding-top: 120px;
  padding-bottom: var(--space-7);
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
  align-items: center;
  max-width: 1120px;
  margin: 0 auto;
  padding-left: var(--space-4);
  padding-right: var(--space-4);
}

.hero-content { animation: slideInLeft 0.8s ease forwards; }

.hero-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--signal);
  margin-bottom: var(--space-3);
}

.hero-title {
  font-size: 48px;
  font-weight: 700;
  line-height: 1.15;
  letter-spacing: -0.03em;
  margin-bottom: var(--space-4);
}

.hero-title .accent { color: var(--signal); }

.hero-desc {
  font-size: 17px;
  line-height: 1.7;
  color: var(--text-secondary);
  margin-bottom: var(--space-4);
  max-width: 480px;
}

.hero-actions {
  display: flex;
  gap: var(--space-3);
  margin-bottom: var(--space-5);
}

.hero-vendors {
  display: flex;
  gap: var(--space-3);
  flex-wrap: wrap;
}

.hero-vendors span {
  font-size: 13px;
  font-weight: 700;
  color: var(--text-secondary);
  padding: 4px 12px;
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.hero-image {
  animation: slideInRight 0.8s ease 0.2s forwards;
  opacity: 0;
}

.hero-image img {
  width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

/* --- Buttons --- */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  background: var(--ink);
  color: var(--canvas);
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 700;
  border: none;
  cursor: pointer;
  transition: background var(--transition), transform 100ms ease;
  text-decoration: none;
}

.btn-primary:hover { background: #222; text-decoration: none; transform: translateY(-1px); }
.btn-primary:active { transform: translateY(0); }

.btn-secondary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  background: transparent;
  color: var(--ink);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: border-color var(--transition), transform 100ms ease;
  text-decoration: none;
}

.btn-secondary:hover { border-color: var(--ink); text-decoration: none; transform: translateY(-1px); }
.btn-secondary:active { transform: translateY(0); }

.btn-lg { padding: 16px 36px; font-size: 16px; }

/* --- Problem Section --- */
.problem {
  padding: var(--space-7) 0;
  background: var(--bg-subtle);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.problem-grid {
  display: grid;
  grid-template-columns: 1fr 1fr 1fr;
  gap: var(--space-4);
}

.problem-card {
  padding: var(--space-5);
  background: var(--canvas);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.problem-num {
  font-size: 40px;
  font-weight: 700;
  color: var(--border);
  line-height: 1;
  display: block;
  margin-bottom: var(--space-3);
}

.problem-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: var(--space-2);
}

.problem-card p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* --- Section Headers --- */
.section-header {
  margin-bottom: var(--space-6);
}

.section-tag {
  display: inline-block;
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--signal);
  margin-bottom: var(--space-2);
}

.section-title {
  font-size: 36px;
  font-weight: 700;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.section-title .accent { color: var(--signal); }

/* --- Calculator --- */
.calculator-section {
  padding: var(--space-7) 0;
}

.calc-layout {
  display: grid;
  grid-template-columns: 1fr 1.4fr;
  gap: var(--space-5);
  align-items: start;
}

.calc-inputs {
  padding: var(--space-5);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--bg-subtle);
}

.input-group {
  margin-bottom: var(--space-3);
}

.input-group label {
  display: block;
  font-size: 14px;
  font-weight: 700;
  margin-bottom: var(--space-1);
}

.input-with-unit {
  display: flex;
  align-items: center;
  border: 1px solid var(--border);
  border-radius: var(--radius);
  background: var(--canvas);
  overflow: hidden;
  transition: border-color var(--transition);
}

.input-with-unit:focus-within { border-color: var(--signal); }

.input-with-unit input {
  flex: 1;
  padding: 12px;
  border: none;
  font-family: var(--font-mono);
  font-size: 16px;
  font-weight: 400;
  outline: none;
  background: transparent;
  -moz-appearance: textfield;
  min-height: 44px;
}

.input-with-unit input::-webkit-inner-spin-button,
.input-with-unit input::-webkit-outer-spin-button {
  -webkit-appearance: none;
}

.input-unit {
  padding: 10px 12px;
  font-size: 14px;
  color: var(--text-secondary);
  background: var(--bg-subtle);
  border-left: 1px solid var(--border);
  min-width: 44px;
  text-align: center;
}

.input-group label.checkbox-label {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  cursor: pointer;
  font-weight: 400;
}

.checkbox-label input[type="checkbox"] {
  width: 24px;
  height: 24px;
  accent-color: var(--signal);
  cursor: pointer;
  flex-shrink: 0;
}

.btn-calc {
  width: 100%;
  margin-top: var(--space-3);
  padding: 14px;
  font-size: 16px;
}

/* --- Results Panel --- */
.calc-results {
  padding: var(--space-5);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  min-height: 400px;
  position: relative;
}

.results-placeholder {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 360px;
  text-align: center;
  color: var(--text-secondary);
  font-size: 16px;
  line-height: 1.8;
}

.results-title {
  font-size: 20px;
  font-weight: 700;
  margin-bottom: var(--space-4);
  padding-bottom: var(--space-3);
  border-bottom: 1px solid var(--border);
}

/* --- Vendor Result Cards --- */
.vendor-card {
  display: grid;
  grid-template-columns: 1fr auto auto auto;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) 0;
  border-bottom: 1px solid var(--border);
  animation: countUp 0.4s ease forwards;
  opacity: 0;
}

.vendor-card:last-of-type { border-bottom: none; }

.vendor-name {
  font-weight: 700;
  font-size: 15px;
}

.vendor-model {
  font-size: 13px;
  color: var(--text-secondary);
}

.vendor-cost-usd {
  font-family: var(--font-mono);
  font-size: 15px;
  text-align: right;
  min-width: 80px;
}

.vendor-cost-krw {
  font-family: var(--font-mono);
  font-size: 15px;
  font-weight: 700;
  text-align: right;
  min-width: 100px;
}

/* --- Summary --- */
.results-summary {
  margin-top: var(--space-4);
  padding-top: var(--space-4);
  border-top: 2px solid var(--ink);
}

.summary-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: var(--space-2) 0;
}

.summary-label {
  font-size: 14px;
  color: var(--text-secondary);
}

.summary-value {
  font-family: var(--font-mono);
  font-size: 18px;
  font-weight: 700;
}

.summary-annual {
  font-size: 24px;
  color: var(--signal);
}

.btn-consult {
  width: 100%;
  margin-top: var(--space-4);
  text-align: center;
  background: var(--signal);
}

.btn-consult:hover { background: #003d99; }

/* --- Comparison Table --- */
.comparison-section {
  padding: var(--space-7) 0;
  background: var(--bg-subtle);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.comparison-table-wrap {
  overflow-x: auto;
  -webkit-overflow-scrolling: touch;
}

.comparison-table {
  width: 100%;
  border-collapse: collapse;
  background: var(--canvas);
  border: 1px solid var(--border);
  border-radius: var(--radius);
}

.comparison-table th {
  padding: 14px 20px;
  text-align: left;
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  background: var(--bg-subtle);
  border-bottom: 2px solid var(--ink);
}

.comparison-table td {
  padding: 14px 20px;
  font-size: 15px;
  border-bottom: 1px solid var(--border);
}

.comparison-table tr:last-child td { border-bottom: none; }

.comparison-table tbody tr {
  transition: background var(--transition);
}

.comparison-table tbody tr:hover { background: var(--signal-light); }

/* --- Savings Section --- */
.savings-section {
  padding: var(--space-7) 0;
}

.savings-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-6);
  align-items: center;
}

.savings-image img {
  width: 100%;
  border-radius: var(--radius);
  border: 1px solid var(--border);
}

.savings-content .section-title {
  margin-bottom: var(--space-4);
}

.savings-list {
  list-style: none;
  margin-bottom: var(--space-5);
}

.savings-list li {
  padding: var(--space-2) 0;
  padding-left: var(--space-4);
  position: relative;
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.6;
}

.savings-list li::before {
  content: '';
  position: absolute;
  left: 0;
  top: 14px;
  width: 8px;
  height: 8px;
  background: var(--signal);
  border-radius: 50%;
}

/* --- Features --- */
.features-section {
  padding: var(--space-7) 0;
  background: var(--bg-subtle);
  border-top: 1px solid var(--border);
  border-bottom: 1px solid var(--border);
}

.features-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--space-4);
}

.feature-card {
  padding: var(--space-5);
  background: var(--canvas);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  transition: border-color var(--transition);
}

.feature-card:hover { border-color: var(--signal); }

.feature-icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--signal);
  margin-bottom: var(--space-3);
}

.feature-card h3 {
  font-size: 18px;
  font-weight: 700;
  margin-bottom: var(--space-2);
}

.feature-card p {
  font-size: 15px;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* --- CTA Section --- */
.cta-section {
  padding: var(--space-7) 0;
  text-align: center;
}

.cta-content { max-width: 560px; margin: 0 auto; }

.cta-title {
  font-size: 32px;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-bottom: var(--space-3);
}

.cta-desc {
  font-size: 17px;
  color: var(--text-secondary);
  margin-bottom: var(--space-5);
  line-height: 1.7;
}

.cta-actions {
  display: flex;
  gap: var(--space-3);
  justify-content: center;
}

/* --- Footer --- */
.footer {
  padding: var(--space-5) 0;
  border-top: 1px solid var(--border);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-3);
}

.footer-logo {
  font-size: 16px;
  font-weight: 700;
}

.footer-desc {
  font-size: 14px;
  color: var(--text-secondary);
}

.footer-links {
  display: flex;
  gap: var(--space-4);
}

.footer-links a {
  font-size: 14px;
  color: var(--text-secondary);
  padding: 8px 0;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
}

.footer-copy {
  font-size: 13px;
  color: var(--text-secondary);
  padding-top: var(--space-3);
  border-top: 1px solid var(--border);
}

/* --- Responsive --- */
@media (max-width: 768px) {
  .hero {
    grid-template-columns: 1fr;
    padding-top: 100px;
    gap: var(--space-4);
  }

  .hero-title { font-size: 32px; }
  .hero-image { display: none; }
  .hero-actions { flex-direction: column; }
  .hero-actions .btn-primary,
  .hero-actions .btn-secondary { width: 100%; text-align: center; }

  .problem-grid { grid-template-columns: 1fr; }
  .calc-layout { grid-template-columns: 1fr; }
  .section-title { font-size: 28px; }

  .savings-layout { grid-template-columns: 1fr; }
  .features-grid { grid-template-columns: 1fr; }
  .comparison-table { font-size: 13px; }
  .comparison-table th, .comparison-table td { padding: 10px 12px; }

  .cta-actions { flex-direction: column; }
  .cta-title { font-size: 24px; }

  .nav-links a:not(.nav-cta) { display: none; }

  .vendor-card {
    grid-template-columns: 1fr;
    gap: var(--space-1);
  }
}

@media (max-width: 480px) {
  .hero-title { font-size: 28px; }
  .container { padding: 0 var(--space-3); }
}

/* --- Intersection Observer Animation Trigger --- */
.visible { animation-play-state: running; }

/* --- Focus Styles --- */
input:focus-visible,
button:focus-visible,
a:focus-visible {
  outline: 2px solid var(--signal);
  outline-offset: 2px;
}

/* --- Print --- */
@media print {
  .header, .cta-section, .cta-actions, .nav, .btn-consult { display: none; }
  body { font-size: 12pt; }
}