/* ── modern minimalist theme reset ── */
:root {
  --bg: #f8fafc;            /* Soft light background */
  --surface: #ffffff;       /* Card background */
  --surface-hover: #f1f5f9;
  --surface-border: #e2e8f0;/* Slate-200 border */
  --primary: #4f46e5;       /* Premium indigo brand color */
  --primary-hover: #4338ca;
  --primary-light: rgba(79, 70, 229, 0.05);
  --text: #0f172a;          /* Slate-900 typography */
  --text-muted: #475569;    /* Slate-600 */
  --text-dark: #64748b;     /* Slate-500 */
  --success: #10b981;       /* Emerald success green */
  --radius: 12px;
  --radius-sm: 8px;
  --font: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --transition: all 0.15s cubic-bezier(0.4, 0, 0.2, 1);
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.05), 0 2px 4px -2px rgba(0, 0, 0, 0.05);
  --shadow-md: 0 10px 15px -3px rgba(0, 0, 0, 0.04), 0 4px 6px -4px rgba(0, 0, 0, 0.04);
  --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.05), 0 8px 10px -6px rgba(0, 0, 0, 0.05);
}

*, *::before, *::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  padding: 0;
  background-color: var(--bg);
  color: var(--text);
  font-family: var(--font);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
  line-height: 1.5;
}

.container {
  width: 100%;
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 24px;
}

section {
  padding: 60px 0;
}

/* Typography */
h1, h2, h3, h4 {
  color: var(--text);
  font-weight: 700;
  margin-top: 0;
  letter-spacing: -0.03em;
}

/* Minimalist Header */
.site-header {
  position: sticky;
  top: 0;
  background: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--surface-border);
  z-index: 999;
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
}

.logo-icon {
  font-size: 1.4rem;
}

.logo-text {
  font-weight: 800;
  font-size: 1.2rem;
  color: var(--text) !important;
  letter-spacing: -0.5px;
}

.header-nav-container {
  display: flex;
  align-items: center;
  gap: 32px;
}

.desktop-nav {
  display: flex;
  gap: 24px;
}

.desktop-nav a {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-muted);
  text-decoration: none;
}

.desktop-nav a:hover {
  color: var(--primary);
}

/* Switcher Button and Modal */
.lang-trigger {
  background: #ffffff;
  border: 1px solid var(--surface-border);
  color: var(--text-muted);
  padding: 8px 14px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: 600;
  font-size: 0.82rem;
  display: flex;
  align-items: center;
  gap: 6px;
  transition: var(--transition);
  box-shadow: var(--shadow-sm);
}

.lang-trigger:hover {
  background: var(--bg);
  border-color: var(--text-dark);
}

.lang-modal-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100vw;
  height: 100vh;
  background: rgba(15, 23, 42, 0.25);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  z-index: 10000;
  align-items: center;
  justify-content: center;
}

.lang-modal-overlay.is-open {
  display: flex;
}

.lang-modal-card {
  background: #ffffff;
  width: 90%;
  max-width: 480px;
  border-radius: var(--radius);
  border: 1px solid var(--surface-border);
  box-shadow: var(--shadow-lg);
  padding: 24px;
  animation: modalSlide 0.2s cubic-bezier(0.16, 1, 0.3, 1) forwards;
}

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

.lang-modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.lang-modal-header h3 {
  font-size: 1.1rem;
  margin: 0;
}

.lang-modal-close {
  background: transparent;
  border: none;
  color: var(--text-dark);
  font-size: 1.6rem;
  cursor: pointer;
  padding: 0;
}

.lang-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px;
}

.lang-btn {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 12px 16px;
  background: #f8fafc;
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-sm);
  color: var(--text);
  font-weight: 600;
  font-size: 0.88rem;
  text-decoration: none;
}

.lang-btn:hover {
  background: var(--surface-hover);
  border-color: var(--primary);
}

.lang-btn.active {
  background: var(--primary) !important;
  border-color: var(--primary) !important;
  color: #ffffff !important;
}

.lang-code {
  font-size: 0.72rem;
  color: var(--text-dark);
}

.lang-btn.active .lang-code {
  color: rgba(255, 255, 255, 0.8);
}

/* Hero */
.page-hero {
  text-align: center;
  padding: 80px 0 50px;
  background: linear-gradient(180deg, #f5f3ff 0%, var(--bg) 100%); /* Soft modern indigo-gray tint */
  border-bottom: 1px solid var(--surface-border);
}

.hero-badge {
  background: var(--primary-light);
  color: var(--primary);
  border: 1px solid rgba(79, 70, 229, 0.15);
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  padding: 6px 14px;
  border-radius: 50px;
  display: inline-block;
  margin-bottom: 16px;
}

.page-hero h1 {
  font-size: 2.5rem;
  letter-spacing: -0.8px;
  margin-bottom: 12px;
}

.page-hero p {
  color: var(--text-muted);
  font-size: 1.05rem;
  max-width: 640px;
  margin: 0 auto;
  line-height: 1.5;
}

/* Interactive Calculator (Clockify/LogMyHours layout) */
.tool-section {
  padding-top: 0;
  margin-top: -30px;
}

.tool-card {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius);
  padding: 32px;
  max-width: 720px;
  margin: 0 auto;
  box-shadow: var(--shadow-lg);
}

.converter-box {
  display: flex;
  align-items: center;
  gap: 20px;
}

.input-container {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.input-container label {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
}

.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.input-wrapper input {
  width: 100%;
  height: 54px; /* Spacious mobile targets */
  background: #f8fafc;
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-sm);
  padding: 0 54px 0 18px;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--text);
  outline: none;
  font-family: inherit;
  transition: var(--transition);
}

.input-wrapper input:focus {
  border-color: var(--primary);
  background: #ffffff;
  box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.12);
}

.input-suffix {
  position: absolute;
  right: 18px;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--text-dark);
  background: var(--surface-hover);
  padding: 4px 8px;
  border-radius: var(--radius-sm);
  border: 1px solid var(--surface-border);
}

/* Swap icon styling */
.swap-divider {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 54px;
  margin-top: 26px;
}

.swap-icon {
  font-size: 1.6rem;
  color: var(--text-dark);
  cursor: default;
  user-select: none;
}

/* Explanation Panel */
.explanation-box {
  display: none; /* Only visible when typing */
  margin-top: 24px;
  background: var(--bg);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-sm);
}

.explanation-box.is-active {
  display: block;
}

.explanation-inner {
  padding: 16px 20px;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.explanation-inner strong {
  display: block;
  color: var(--text);
  margin-bottom: 4px;
}

.explanation-inner p {
  margin: 0;
}

/* Charts */
.charts-section h2 {
  text-align: center;
  font-size: 1.5rem;
  margin-bottom: 28px;
}

.chart-tabs {
  display: flex;
  justify-content: center;
  gap: 10px;
  margin-bottom: 24px;
}

.chart-tab {
  background: #ffffff;
  border: 1px solid var(--surface-border);
  color: var(--text-muted);
  padding: 10px 20px;
  border-radius: 50px;
  cursor: pointer;
  font-weight: 600;
  font-size: 0.85rem;
  box-shadow: var(--shadow-sm);
}

.chart-tab.active {
  background: var(--primary);
  border-color: var(--primary);
  color: #ffffff;
  box-shadow: var(--shadow);
}

.table-container {
  overflow-x: auto;
  border: 1px solid var(--surface-border);
  border-radius: var(--radius);
  background: var(--surface);
  box-shadow: var(--shadow-sm);
}

table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.9rem;
}

th, td {
  padding: 12px 20px;
  border-bottom: 1px solid var(--surface-border);
}

th {
  background: #f8fafc;
  color: var(--text-muted);
  font-weight: 700;
}

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

tr:hover td {
  background: #f8fafc;
}

/* Excel formulas box */
.excel-card {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius);
  padding: 24px;
  display: flex;
  gap: 20px;
  align-items: center;
  box-shadow: var(--shadow-md);
}

.excel-icon {
  font-size: 2.5rem;
}

.excel-content {
  flex: 1;
}

.excel-content h3 {
  font-size: 1.05rem;
  margin-bottom: 4px;
}

.excel-content p {
  color: var(--text-muted);
  font-size: 0.88rem;
  margin: 0 0 16px 0;
}

.excel-code-box {
  display: flex;
  background: #f8fafc;
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-sm);
  padding: 4px;
  align-items: center;
}

.excel-code-box code {
  flex: 1;
  padding: 0 16px;
  font-family: monospace;
  font-size: 0.88rem;
  color: var(--primary);
  overflow-x: auto;
}

.btn-copy {
  background: var(--primary);
  border: none;
  color: #ffffff;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: 700;
  font-size: 0.82rem;
  height: 38px;
}

.btn-copy:hover {
  background: var(--primary-hover);
}

.copy-success-toast {
  display: none;
  font-size: 0.8rem;
  color: var(--success);
  font-weight: 700;
  margin-top: 8px;
}

/* FAQs */
.faq-section h2 {
  text-align: center;
  font-size: 1.5rem;
  margin-bottom: 28px;
}

.faq-accordion-group {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.faq-item {
  background: var(--surface);
  border: 1px solid var(--surface-border);
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-sm);
  overflow: hidden;
}

.faq-trigger {
  width: 100%;
  background: transparent;
  border: none;
  padding: 18px 24px;
  color: var(--text);
  font-weight: 600;
  font-size: 0.92rem;
  cursor: pointer;
  text-align: left;
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 16px;
  font-family: inherit;
}

.faq-trigger:hover {
  background: var(--surface-hover);
}

.faq-icon-arrow {
  color: var(--text-dark);
  font-size: 1.1rem;
}

.faq-item.is-open {
  border-color: var(--primary);
}

.faq-item.is-open .faq-icon-arrow {
  transform: rotate(45deg);
  color: var(--primary);
}

.faq-answer {
  border-top: 1px solid var(--surface-border);
  background: #f8fafc;
}

.faq-answer-inner {
  padding: 18px 24px;
  color: var(--text-muted);
  font-size: 0.88rem;
}

.faq-answer-inner p {
  margin: 0;
}

/* Footer */
.site-footer {
  background-color: #ffffff;
  border-top: 1px solid var(--surface-border);
  color: var(--text-muted);
  padding: 64px 0 32px;
}

.footer-grid {
  display: grid;
  grid-template-columns: 1.2fr 1fr 1fr;
  gap: 40px;
  margin-bottom: 48px;
}

.footer-brand {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.footer-brand p {
  font-size: 0.85rem;
  color: var(--text-muted);
  margin: 0;
}

.footer-badges {
  display: flex;
  gap: 8px;
}

.footer-badge {
  background: #f1f5f9;
  border: 1px solid var(--surface-border);
  color: var(--text-dark);
  padding: 4px 10px;
  border-radius: 6px;
  font-size: 0.72rem;
  font-weight: 700;
}

.footer-col h4 {
  font-size: 0.78rem;
  color: var(--text);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 20px;
}

.footer-col ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-col ul li a {
  font-size: 0.88rem;
  color: var(--text-muted);
  text-decoration: none;
}

.footer-col ul li a:hover {
  color: var(--primary);
}

.footer-bottom {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 24px;
  border-top: 1px solid var(--surface-border);
  font-size: 0.82rem;
  color: var(--text-dark);
}

/* Responsive constraints */
@media (max-width: 768px) {
  .footer-grid {
    grid-template-columns: 1fr;
    gap: 32px;
  }
  .excel-card {
    flex-direction: column;
    text-align: center;
    gap: 16px;
  }
  .desktop-nav {
    display: none;
  }
}

@media (max-width: 640px) {
  .converter-box {
    flex-direction: column;
    gap: 12px;
  }
  .swap-divider {
    height: 32px;
    margin-top: 0;
    transform: rotate(90deg); /* Swaps the arrow vertical on mobile */
  }
  .input-container {
    width: 100%;
  }
}

@media (max-width: 480px) {
  h1 { font-size: 2rem !important; }
  .page-hero { padding: 60px 0 30px; }
  .tool-card { padding: 20px; }
  .lang-grid { grid-template-columns: 1fr; }
  .footer-bottom { flex-direction: column; text-align: center; gap: 12px; }
}