/* ===== CSS Variables & Reset ===== */
:root {
  --color-bg: #FAFAF8;
  --color-surface: #FFFFFF;
  --color-surface-alt: #F3F1ED;
  --color-border: #E2DFD8;
  --color-text: #1A1A18;
  --color-text-secondary: #6B6860;
  --color-text-muted: #9B978E;
  --color-primary: #1B6B4A;
  --color-primary-dark: #14503A;
  --color-primary-light: #E8F5EE;
  --color-accent: #D4A853;
  --color-accent-light: #FDF6E7;
  --color-danger: #C4402A;
  --color-info-bg: #EEF4FF;
  --color-info-border: #B8D0F0;
  --font-display: 'DM Serif Display', Georgia, serif;
  --font-body: 'Source Sans 3', 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', monospace;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.04), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.06), 0 1px 4px rgba(0,0,0,0.04);
  --shadow-lg: 0 12px 40px rgba(0,0,0,0.08), 0 4px 12px rgba(0,0,0,0.04);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --max-width: 1140px;
  --transition: 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

*, *::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;
}

body {
  font-family: var(--font-body);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.7;
}

img { max-width: 100%; display: block; }
a { color: var(--color-primary); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-primary-dark); }

/* ===== Typography ===== */
h1, h2, h3, h4 { font-family: var(--font-display); font-weight: 400; line-height: 1.25; }
h1 { font-size: clamp(2rem, 4.5vw, 3rem); letter-spacing: -0.01em; }
h2 { font-size: clamp(1.5rem, 3vw, 2.1rem); }
h3 { font-size: clamp(1.2rem, 2vw, 1.5rem); }
p { margin-bottom: 1rem; }

/* ===== Layout ===== */
.container { max-width: var(--max-width); margin: 0 auto; padding: 0 1.5rem; }
.section { padding: 4rem 0; }

/* ===== Header / Nav ===== */
.site-header {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(12px);
  background: rgba(255,255,255,0.92);
}
.nav-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}
.logo {
  font-family: var(--font-display);
  font-size: 1.35rem;
  color: var(--color-text);
  display: flex;
  align-items: center;
  gap: 0.5rem;
}
.logo-icon {
  width: 32px;
  height: 32px;
  background: var(--color-primary);
  border-radius: var(--radius-sm);
  display: grid;
  place-items: center;
  color: white;
  font-size: 0.85rem;
  font-weight: 700;
  font-family: var(--font-mono);
}
.nav-links { display: flex; gap: 2rem; align-items: center; list-style: none; }
.nav-links a {
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  font-weight: 500;
  position: relative;
  padding: 0.25rem 0;
}
.nav-links a::after {
  content: '';
  position: absolute;
  bottom: -2px;
  left: 0;
  width: 0;
  height: 2px;
  background: var(--color-primary);
  transition: width var(--transition);
}
.nav-links a:hover::after,
.nav-links a.active::after { width: 100%; }
.nav-links a:hover, .nav-links a.active { color: var(--color-primary); }

/* Mobile nav */
.nav-toggle { display: none; background: none; border: none; cursor: pointer; padding: 0.5rem; }
.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--color-text);
  margin: 5px 0;
  transition: var(--transition);
}

@media (max-width: 768px) {
  .nav-toggle { display: block; }
  .nav-links {
    display: none;
    position: absolute;
    top: 64px;
    left: 0;
    right: 0;
    background: var(--color-surface);
    flex-direction: column;
    padding: 1.5rem;
    gap: 1rem;
    border-bottom: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
  }
  .nav-links.open { display: flex; }
}

/* ===== Hero ===== */
.hero {
  padding: 3.5rem 0 2rem;
  text-align: center;
}
.hero-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  background: var(--color-primary-light);
  color: var(--color-primary);
  font-size: 0.8rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 0.35rem 1rem;
  border-radius: 50px;
  margin-bottom: 1.25rem;
}
.hero h1 { margin-bottom: 0.75rem; }
.hero p {
  font-size: 1.15rem;
  color: var(--color-text-secondary);
  max-width: 620px;
  margin: 0 auto 1.5rem;
}

/* ===== Calculator Card ===== */
.calc-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
  max-width: 960px;
  margin: 0 auto;
  overflow: hidden;
}
.calc-body {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0;
}
@media (max-width: 768px) {
  .calc-body { grid-template-columns: 1fr; }
}

/* Input side */
.calc-inputs {
  padding: 2.25rem;
  display: flex;
  flex-direction: column;
  gap: 1.35rem;
}
.input-group { display: flex; flex-direction: column; gap: 0.4rem; }
.input-group label {
  font-size: 0.82rem;
  font-weight: 600;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.06em;
}
.input-wrap {
  position: relative;
  display: flex;
  align-items: center;
}
.input-prefix, .input-suffix {
  position: absolute;
  color: var(--color-text-muted);
  font-size: 0.95rem;
  font-weight: 500;
  pointer-events: none;
}
.input-prefix { left: 14px; }
.input-suffix { right: 14px; }
.input-wrap input {
  width: 100%;
  padding: 0.75rem 1rem;
  font-size: 1.05rem;
  font-family: var(--font-body);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  color: var(--color-text);
  transition: border-color var(--transition), box-shadow var(--transition);
}
.input-wrap input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(27,107,74,0.1);
}
.input-wrap input.has-prefix { padding-left: 28px; }
.input-wrap input.has-suffix { padding-right: 40px; }

.extra-payment-section {
  background: var(--color-accent-light);
  border: 1px dashed var(--color-accent);
  border-radius: var(--radius-md);
  padding: 1rem 1.25rem;
}
.extra-payment-section .input-group label { color: var(--color-accent); }

.btn-calculate {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.85rem 2rem;
  background: var(--color-primary);
  color: white;
  font-family: var(--font-body);
  font-size: 1rem;
  font-weight: 600;
  border: none;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background var(--transition), transform 0.15s ease;
  margin-top: 0.5rem;
}
.btn-calculate:hover { background: var(--color-primary-dark); transform: translateY(-1px); }
.btn-calculate:active { transform: translateY(0); }

/* Results side */
.calc-results {
  background: var(--color-surface-alt);
  padding: 2.25rem;
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  border-left: 1px solid var(--color-border);
}
@media (max-width: 768px) {
  .calc-results { border-left: none; border-top: 1px solid var(--color-border); }
}
.results-title {
  font-family: var(--font-display);
  font-size: 1.15rem;
  color: var(--color-text-secondary);
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--color-border);
}
.result-item {
  display: flex;
  justify-content: space-between;
  align-items: baseline;
  padding: 0.35rem 0;
}
.result-label {
  font-size: 0.9rem;
  color: var(--color-text-secondary);
}
.result-value {
  font-family: var(--font-mono);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--color-text);
}
.result-value.highlight {
  color: var(--color-primary);
  font-size: 1.3rem;
}
.result-value.savings { color: var(--color-primary); }

.savings-box {
  background: var(--color-primary-light);
  border: 1px solid rgba(27,107,74,0.2);
  border-radius: var(--radius-md);
  padding: 1.15rem;
  text-align: center;
}
.savings-box .savings-label {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  font-weight: 600;
  color: var(--color-primary);
  margin-bottom: 0.25rem;
}
.savings-box .savings-amount {
  font-family: var(--font-mono);
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--color-primary-dark);
}
.savings-box .savings-time {
  font-size: 0.88rem;
  color: var(--color-primary);
  margin-top: 0.2rem;
}

/* Amortization table */
.amort-toggle {
  background: none;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  padding: 0.6rem 1rem;
  font-family: var(--font-body);
  font-size: 0.88rem;
  font-weight: 500;
  color: var(--color-text-secondary);
  cursor: pointer;
  transition: var(--transition);
  text-align: center;
}
.amort-toggle:hover { border-color: var(--color-primary); color: var(--color-primary); }

.amort-section {
  max-width: 960px;
  margin: 2rem auto 0;
  display: none;
}
.amort-section.visible { display: block; }
.amort-table-wrap {
  max-height: 420px;
  overflow-y: auto;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-surface);
}
.amort-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.88rem;
}
.amort-table thead { position: sticky; top: 0; z-index: 2; }
.amort-table th {
  background: var(--color-surface-alt);
  padding: 0.75rem 1rem;
  text-align: right;
  font-weight: 600;
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--color-text-secondary);
  border-bottom: 2px solid var(--color-border);
}
.amort-table th:first-child { text-align: left; }
.amort-table td {
  padding: 0.6rem 1rem;
  text-align: right;
  border-bottom: 1px solid var(--color-border);
  font-family: var(--font-mono);
  font-size: 0.82rem;
}
.amort-table td:first-child { text-align: left; font-family: var(--font-body); font-weight: 500; }
.amort-table tbody tr:hover { background: var(--color-surface-alt); }

/* ===== How-It-Works ===== */
.how-it-works { background: var(--color-surface); border-top: 1px solid var(--color-border); }
.section-header {
  text-align: center;
  max-width: 540px;
  margin: 0 auto 2.5rem;
}
.section-header p { color: var(--color-text-secondary); }
.steps-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 2rem;
}
@media (max-width: 768px) { .steps-grid { grid-template-columns: 1fr; } }
.step-card {
  text-align: center;
  padding: 2rem 1.5rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-border);
  background: var(--color-bg);
  transition: box-shadow var(--transition), transform var(--transition);
}
.step-card:hover { box-shadow: var(--shadow-md); transform: translateY(-3px); }
.step-num {
  width: 44px;
  height: 44px;
  background: var(--color-primary);
  color: white;
  font-family: var(--font-display);
  font-size: 1.25rem;
  border-radius: 50%;
  display: grid;
  place-items: center;
  margin: 0 auto 1rem;
}
.step-card h3 { margin-bottom: 0.5rem; }
.step-card p { color: var(--color-text-secondary); font-size: 0.95rem; margin: 0; }

/* ===== FAQ ===== */
.faq-section { max-width: 720px; margin: 0 auto; }
.faq-item {
  border-bottom: 1px solid var(--color-border);
}
.faq-question {
  width: 100%;
  text-align: left;
  background: none;
  border: none;
  padding: 1.25rem 0;
  font-family: var(--font-body);
  font-size: 1.05rem;
  font-weight: 600;
  color: var(--color-text);
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1rem;
  transition: color var(--transition);
}
.faq-question:hover { color: var(--color-primary); }
.faq-icon {
  flex-shrink: 0;
  width: 24px;
  height: 24px;
  border-radius: 50%;
  border: 1.5px solid var(--color-border);
  display: grid;
  place-items: center;
  font-size: 1.1rem;
  color: var(--color-text-muted);
  transition: var(--transition);
}
.faq-item.open .faq-icon { transform: rotate(45deg); background: var(--color-primary); color: white; border-color: var(--color-primary); }
.faq-answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height 0.35s ease, padding 0.35s ease;
}
.faq-answer-inner {
  padding: 0 0 1.25rem;
  color: var(--color-text-secondary);
  font-size: 0.95rem;
  line-height: 1.75;
}

/* ===== Blog Cards ===== */
.blog-preview { background: var(--color-surface); border-top: 1px solid var(--color-border); }
.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 1.75rem;
  margin-top: 2rem;
}
.blog-card {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  transition: box-shadow var(--transition), transform var(--transition);
  background: var(--color-bg);
}
.blog-card:hover { box-shadow: var(--shadow-md); transform: translateY(-3px); }
.blog-card-img {
  height: 180px;
  background: linear-gradient(135deg, var(--color-primary-light), var(--color-accent-light));
  display: grid;
  place-items: center;
  font-size: 3rem;
}
.blog-card-body { padding: 1.5rem; }
.blog-card-tag {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-primary);
  margin-bottom: 0.5rem;
}
.blog-card-body h3 { margin-bottom: 0.5rem; font-size: 1.15rem; }
.blog-card-body h3 a { color: var(--color-text); }
.blog-card-body h3 a:hover { color: var(--color-primary); }
.blog-card-body p { color: var(--color-text-secondary); font-size: 0.9rem; margin: 0; }
.blog-card-meta {
  padding: 0.75rem 1.5rem;
  border-top: 1px solid var(--color-border);
  font-size: 0.8rem;
  color: var(--color-text-muted);
  display: flex;
  justify-content: space-between;
}

/* ===== Blog Post Page ===== */
.blog-hero {
  padding: 3rem 0 2rem;
  border-bottom: 1px solid var(--color-border);
  background: var(--color-surface);
}
.breadcrumb {
  font-size: 0.85rem;
  color: var(--color-text-muted);
  margin-bottom: 1.5rem;
}
.breadcrumb a { color: var(--color-text-secondary); }
.breadcrumb a:hover { color: var(--color-primary); }
.blog-meta {
  display: flex;
  align-items: center;
  gap: 1.5rem;
  margin-top: 1rem;
  font-size: 0.88rem;
  color: var(--color-text-muted);
}
.blog-content {
  max-width: 720px;
  margin: 0 auto;
  padding: 3rem 1.5rem;
}
.blog-content h2 { margin: 2.5rem 0 1rem; }
.blog-content h3 { margin: 2rem 0 0.75rem; }
.blog-content p { margin-bottom: 1.25rem; color: var(--color-text-secondary); }
.blog-content ul, .blog-content ol {
  margin: 0 0 1.5rem 1.5rem;
  color: var(--color-text-secondary);
}
.blog-content li { margin-bottom: 0.5rem; }
.blog-content blockquote {
  border-left: 3px solid var(--color-primary);
  padding: 1rem 1.5rem;
  margin: 1.5rem 0;
  background: var(--color-primary-light);
  border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
  font-style: italic;
  color: var(--color-text-secondary);
}

.cta-box {
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-dark));
  color: white;
  padding: 2rem;
  border-radius: var(--radius-md);
  text-align: center;
  margin: 2.5rem 0;
}
.cta-box h3 { color: white; margin-bottom: 0.5rem; font-size: 1.3rem; }
.cta-box p { color: rgba(255,255,255,0.85); margin-bottom: 1.25rem; }
.cta-box a {
  display: inline-block;
  background: white;
  color: var(--color-primary);
  font-weight: 600;
  padding: 0.7rem 1.75rem;
  border-radius: var(--radius-sm);
  transition: transform 0.15s ease, box-shadow var(--transition);
}
.cta-box a:hover { transform: translateY(-2px); box-shadow: 0 4px 12px rgba(0,0,0,0.2); }

/* ===== Blog Listing ===== */
.blog-listing-hero {
  padding: 3rem 0 2rem;
  text-align: center;
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
}

/* ===== Footer ===== */
.site-footer {
  background: var(--color-text);
  color: rgba(255,255,255,0.65);
  padding: 3rem 0 1.5rem;
}
.footer-grid {
  display: grid;
  grid-template-columns: 2fr 1fr 1fr;
  gap: 3rem;
  margin-bottom: 2.5rem;
}
@media (max-width: 768px) { .footer-grid { grid-template-columns: 1fr; gap: 2rem; } }
.footer-brand .logo { color: white; margin-bottom: 0.75rem; }
.footer-brand p { font-size: 0.9rem; line-height: 1.6; max-width: 320px; }
.footer-col h4 {
  color: white;
  font-family: var(--font-body);
  font-size: 0.82rem;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 1rem;
  font-weight: 600;
}
.footer-col ul { list-style: none; }
.footer-col li { margin-bottom: 0.5rem; }
.footer-col a { color: rgba(255,255,255,0.6); font-size: 0.9rem; }
.footer-col a:hover { color: white; }
.footer-bottom {
  border-top: 1px solid rgba(255,255,255,0.1);
  padding-top: 1.5rem;
  text-align: center;
  font-size: 0.82rem;
}

/* ===== Utility ===== */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}
.text-center { text-align: center; }

/* ===== Animations ===== */
@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}
.fade-in {
  opacity: 0;
  animation: fadeInUp 0.6s ease forwards;
}
.fade-in:nth-child(2) { animation-delay: 0.1s; }
.fade-in:nth-child(3) { animation-delay: 0.2s; }

/* ===== Print ===== */
@media print {
  .site-header, .site-footer, .btn-calculate, .amort-toggle { display: none; }
  .calc-card { box-shadow: none; border: 1px solid #ccc; }
}