@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --bg-slate-50: #f8fafc;
  --bg-white: #ffffff;
  --text-slate-900: #0f172a;
  --text-slate-600: #475569;
  --text-slate-500: #64748b;
  --primary-blue: #2563eb;
  --primary-hover: #1d4ed8;
  --border-slate-200: #e2e8f0;
  --bg-slate-100: #f1f5f9;
  --success-green: #15803d;
  --success-bg: #dcfce7;
  --danger-red: #b91c1c;
  --danger-bg: #fee2e2;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --radius-lg: 12px;
  --radius-md: 8px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-slate-50);
  color: var(--text-slate-900);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
header {
  background-color: rgba(255, 255, 255, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid rgba(226, 232, 240, 0.8);
  padding: 0.875rem 1.5rem;
  position: sticky;
  top: 0;
  z-index: 40;
}

.header-container {
  max-width: 800px;
  margin: 0 auto;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo-link {
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.625rem;
  transition: all 0.2s ease;
}

.logo-link:hover {
  transform: translateY(-0.5px);
}

.logo-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, #3b82f6, #1d4ed8);
  color: #ffffff;
  border-radius: 8px;
  box-shadow: 0 2px 4px rgba(37, 99, 235, 0.2);
}

.logo-icon svg {
  width: 16px;
  height: 16px;
}

.logo-text {
  font-weight: 700;
  font-size: 1.125rem;
  color: var(--text-slate-900);
  letter-spacing: -0.02em;
}

.logo-text-short {
  display: none;
}

.lang-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  background-color: var(--bg-white);
  border: 1px solid var(--border-slate-200);
  color: var(--text-slate-600);
  padding: 0.45rem 0.8rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
}

.lang-btn:hover {
  background-color: var(--bg-slate-50);
  border-color: var(--text-slate-500);
  color: var(--text-slate-900);
  transform: translateY(-0.5px);
  box-shadow: var(--shadow-md);
}

.lang-btn svg {
  width: 16px;
  height: 16px;
}

.header-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

.more-calcs-link {
  display: inline-flex;
  align-items: center;
  gap: 0.375rem;
  color: var(--primary-blue);
  background-color: var(--bg-white);
  border: 1px solid var(--border-slate-200);
  padding: 0.45rem 0.8rem;
  border-radius: var(--radius-md);
  font-size: 0.875rem;
  font-weight: 600;
  text-decoration: none;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
}

.more-calcs-link:hover {
  background-color: var(--bg-slate-50);
  border-color: var(--text-slate-500);
  color: var(--primary-hover);
  transform: translateY(-0.5px);
  box-shadow: var(--shadow-md);
}

.more-calcs-link svg {
  width: 14px;
  height: 14px;
}

/* Main Container */
main {
  flex: 1;
  max-width: 800px;
  width: 100%;
  margin: 0 auto;
  padding: 2rem 1.5rem;
}

.hero-section {
  text-align: center;
  margin-bottom: 2.5rem;
}

.hero-title {
  font-size: 2.25rem;
  font-weight: 800;
  color: var(--text-slate-900);
  margin-bottom: 0.5rem;
  letter-spacing: -0.025em;
}

.hero-subtitle {
  font-size: 1.125rem;
  color: var(--text-slate-500);
}

/* Cards & Calculator Sentences */
.calc-card {
  background-color: var(--bg-white);
  border: 1px solid var(--border-slate-200);
  border-radius: var(--radius-lg);
  padding: 1.75rem;
  margin-bottom: 1.5rem;
  box-shadow: var(--shadow-sm);
  transition: box-shadow 0.2s ease;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.calc-card:hover {
  box-shadow: var(--shadow-md);
}

.calc-card-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 1.5rem;
  width: 100%;
}

.calc-sentence-left {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 0.75rem;
  font-size: 1.125rem;
  color: var(--text-slate-900);
  font-weight: 500;
  flex: 1;
}

.calc-sentence-left span {
  white-space: nowrap;
}

.calc-inputs-group {
  display: inline-flex;
  align-items: center;
  gap: 0.75rem;
}

.calc-result-right {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  justify-content: flex-end;
}



/* Input Fields */
.calc-input {
  font-family: var(--font-sans);
  font-size: 1.125rem;
  font-weight: 600;
  padding: 0.5rem 0.75rem;
  border: 1px solid var(--border-slate-200);
  border-radius: var(--radius-md);
  color: var(--text-slate-900);
  background-color: var(--bg-slate-100);
  width: 120px;
  text-align: center;
  transition: all 0.2s ease;
  outline: none;
}

.calc-input:focus {
  border-color: var(--primary-blue);
  background-color: var(--bg-white);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.15);
}

/* Inputs width optimization for mobile */
@media (max-width: 640px) {
  .calc-card-row {
    flex-direction: column;
    align-items: stretch;
    gap: 1rem;
  }
  .calc-input {
    flex-grow: 1;
    min-width: 80px;
    width: auto;
  }
  .calc-sentence-left {
    flex-direction: row;
    gap: 0.5rem;
    width: 100%;
  }
  .calc-result-right {
    justify-content: flex-start;
    width: 100%;
  }
  .calc-inputs-group {
    display: contents;
  }
  header {
    padding: 0.75rem 1rem;
  }
}

@media (max-width: 520px) {
  .more-calcs-text {
    display: none;
  }
  .logo-text-full {
    display: inline;
  }
  .logo-text-short {
    display: none;
  }
  .logo-text {
    font-size: 1.05rem;
  }
  .logo-icon {
    width: 28px;
    height: 28px;
    border-radius: 6px;
  }
  .logo-icon svg {
    width: 14px;
    height: 14px;
  }
  .lang-btn {
    padding: 0.35rem 0.6rem;
    font-size: 0.8rem;
  }
  .lang-btn svg {
    width: 14px;
    height: 14px;
  }
  .more-calcs-link {
    padding: 0.35rem 0.6rem;
    font-size: 0.8rem;
  }
  .more-calcs-link svg {
    width: 14px;
    height: 14px;
  }
  .header-actions {
    gap: 0.5rem;
  }
}

@media (max-width: 430px) {
  .logo-text {
    font-size: 1rem;
  }
  .logo-icon {
    width: 24px;
    height: 24px;
    border-radius: 5px;
  }
  .logo-icon svg {
    width: 12px;
    height: 12px;
  }
  .lang-btn {
    padding: 0.3rem 0.5rem;
    font-size: 0.75rem;
  }
  .lang-btn svg {
    display: none;
  }
  .more-calcs-link {
    padding: 0.3rem 0.5rem;
    font-size: 0.75rem;
  }
  .more-calcs-link svg {
    width: 12px;
    height: 12px;
  }
  .header-actions {
    gap: 0.375rem;
  }
  header {
    padding: 0.625rem 0.75rem;
  }
}

/* Result Input/ReadOnly State */
.calc-result {
  font-weight: 700;
  color: var(--primary-blue);
  background-color: var(--bg-slate-50);
  border: 1px dashed var(--primary-blue);
  width: 150px;
  cursor: default;
}

/* Chrome, Safari, Edge, Opera: Hide Spinners */
.calc-input::-webkit-outer-spin-button,
.calc-input::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

/* Firefox: Hide Spinners */
.calc-input[type=number] {
  -moz-appearance: textfield;
}

/* Clear Action and Badges */
.calc-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-top: 1rem;
  padding-top: 0.75rem;
  border-top: 1px solid var(--bg-slate-100);
}

.clear-btn {
  background: none;
  border: none;
  color: var(--text-slate-500);
  font-size: 0.875rem;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  transition: color 0.2s ease;
}

.clear-btn:hover {
  color: var(--danger-red);
}

.clear-btn svg {
  width: 14px;
  height: 14px;
}

.change-badge {
  display: inline-flex;
  align-items: center;
  gap: 0.25rem;
  padding: 0.25rem 0.625rem;
  border-radius: 9999px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  margin-left: auto;
}

.change-badge:empty {
  display: none !important;
}

.badge-increase {
  background-color: var(--success-bg);
  color: var(--success-green);
}

.badge-decrease {
  background-color: var(--danger-bg);
  color: var(--danger-red);
}

.badge-neutral {
  background-color: var(--bg-slate-100);
  color: var(--text-slate-600);
}

/* FAQs */
.faq-section {
  margin-top: 3.5rem;
  border-top: 1px solid var(--border-slate-200);
  padding-top: 2rem;
}

.faq-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--text-slate-900);
  margin-bottom: 1.5rem;
}

.faq-item {
  margin-bottom: 1.5rem;
}

.faq-question {
  font-size: 1.125rem;
  font-weight: 600;
  color: var(--text-slate-900);
  margin-bottom: 0.375rem;
}

.faq-answer {
  color: var(--text-slate-600);
}

/* Footer */
footer {
  background-color: var(--bg-white);
  border-top: 1px solid var(--border-slate-200);
  padding: 2rem 1.5rem;
  margin-top: auto;
  text-align: center;
  color: var(--text-slate-500);
  font-size: 0.875rem;
}

.footer-links {
  margin-top: 0.5rem;
  display: flex;
  justify-content: center;
  flex-wrap: wrap;
  gap: 1rem;
}

.footer-links a {
  color: var(--text-slate-500);
  text-decoration: none;
  transition: color 0.2s;
}

.footer-links a:hover {
  color: var(--primary-blue);
}

/* Custom Modal Overlay */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background-color: rgba(15, 23, 42, 0.4);
  backdrop-filter: blur(8px);
  z-index: 50;
  display: flex;
  justify-content: center;
  align-items: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.25s ease;
  padding: 1rem;
}

.modal-overlay.open {
  opacity: 1;
  pointer-events: auto;
}

.modal-card {
  background-color: var(--bg-white);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 600px;
  max-height: 90vh;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  transform: scale(0.95);
  transition: transform 0.25s ease;
}

.modal-overlay.open .modal-card {
  transform: scale(1);
}

.modal-header {
  padding: 1.25rem 1.5rem;
  border-bottom: 1px solid var(--border-slate-200);
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.modal-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-slate-900);
}

.close-btn {
  background: none;
  border: none;
  color: var(--text-slate-500);
  cursor: pointer;
  padding: 0.25rem;
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background-color 0.2s, color 0.2s;
}

.close-btn:hover {
  background-color: var(--bg-slate-100);
  color: var(--text-slate-900);
}

.close-btn svg {
  width: 20px;
  height: 20px;
}

.modal-body {
  padding: 1.5rem;
}

/* Language Selection Grid */
.lang-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 0.75rem;
}

@media (min-width: 480px) {
  .lang-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (min-width: 640px) {
  .lang-grid {
    grid-template-columns: repeat(3, 1fr);
  }
}

.lang-card {
  display: flex;
  flex-direction: column;
  justify-content: center;
  padding: 0.75rem 1rem;
  border: 1px solid var(--border-slate-200);
  border-radius: var(--radius-md);
  text-decoration: none;
  color: var(--text-slate-900);
  background-color: var(--bg-white);
  transition: all 0.2s ease;
  cursor: pointer;
}

.lang-card:hover {
  border-color: var(--primary-blue);
  background-color: var(--bg-slate-50);
  transform: translateY(-1px);
  box-shadow: var(--shadow-sm);
}

.lang-card.active {
  border-color: var(--primary-blue);
  background-color: var(--bg-slate-100);
  font-weight: 600;
}

.lang-name {
  font-size: 0.95rem;
  color: var(--text-slate-900);
  font-weight: 500;
}

.lang-local {
  font-size: 0.8rem;
  color: var(--text-slate-500);
}

.lang-card.active .lang-name {
  color: var(--primary-blue);
}

/* Global Clear All Button */
.global-actions {
  display: flex;
  justify-content: center;
  margin-bottom: 2rem;
}

.global-clear-btn {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  background-color: var(--bg-white);
  border: 1px solid var(--border-slate-200);
  color: var(--text-slate-600);
  padding: 0.625rem 1.25rem;
  border-radius: var(--radius-md);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s ease;
  box-shadow: var(--shadow-sm);
}

.global-clear-btn:hover {
  background-color: var(--danger-bg);
  border-color: rgba(220, 38, 38, 0.2);
  color: var(--danger-red);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

.global-clear-btn svg {
  width: 16px;
  height: 16px;
}



/* Ad Container */
.ad-container {
  margin: 2rem auto;
  display: flex;
  justify-content: center;
  width: 100%;
}

.ad-slot-mock {
  background-color: var(--bg-slate-100);
  border: 1px dashed var(--border-slate-200);
  border-radius: var(--radius-md);
  color: var(--text-slate-500);
  padding: 1.5rem;
  width: 100%;
  max-width: 728px;
  min-height: 90px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.875rem;
  font-weight: 500;
}