:root {
  --bg-color: #1c1c1e;
  --text-color: #FFFCF2;
  --input-bg: #2c2c2e;
  --button-bg: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
  --accent-color: #8b5cf6;
  --accent-light: #a78bfa;
  --radius: 12px;
  --radius-lg: 20px;
  --card-bg: rgba(44, 44, 46, 0.35);
  --card-border: rgba(255, 255, 255, 0.12);
  --card-shadow: 0 8px 24px rgba(0, 0, 0, 0.4);
}

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

html, body {
  height: 100%;
  font-family: 'Montserrat', sans-serif;
  background: #1c1c1e;
  color: var(--text-color);
  overflow-x: hidden;
  position: relative;
}

.container {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 40px 20px;
  position: relative;
}

.back-btn {
  position: fixed;
  top: 20px;
  left: 20px;
  padding: 12px 20px;
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  color: var(--text-color);
  text-decoration: none;
  font-weight: 600;
  font-size: 0.95rem;
  transition: all 0.25s ease;
  z-index: 100;
}

.back-btn:hover {
  background: var(--accent-color);
  transform: translateX(-3px);
}

.calculator-wrapper {
  max-width: 600px;
  width: 100%;
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--card-shadow);
  overflow: hidden;
  position: relative;
  z-index: 1;
  animation: fadeIn 0.6s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(30px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.calculator-header {
  padding: 32px;
  text-align: center;
  border-bottom: 1px solid rgba(255, 255, 255, 0.1);
}

.calculator-header .title {
  font-size: 1.8rem;
  font-weight: 800;
  margin-bottom: 8px;
  background: linear-gradient(135deg, #8b5cf6 0%, #ec4899 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  display: block;
}

.calculator-header .subtitle {
  font-size: 0.95rem;
  opacity: 0.7;
  display: block;
}

.calculator-body {
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 20px;
  position: relative;
}

.drop-overlay {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(139, 92, 246, 0.95);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.3s ease;
  z-index: 10;
}

.drop-overlay.active {
  opacity: 1;
  pointer-events: all;
}

.drop-content {
  text-align: center;
  animation: dropBounce 0.6s ease;
}

.drop-icon {
  font-size: 4rem;
  animation: floatIcon 0.8s ease-in-out infinite alternate;
  margin-bottom: 12px;
}

.drop-text {
  font-size: 1.2rem;
  font-weight: 600;
  color: #fff;
}

@keyframes dropBounce {
  0% { transform: scale(0.8); opacity: 0; }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); opacity: 1; }
}

@keyframes floatIcon {
  from { transform: translateY(0); }
  to { transform: translateY(-8px); }
}

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

.input-group label {
  font-size: 0.95rem;
  font-weight: 600;
  opacity: 0.9;
  color: var(--text-color);
}

.input-with-icon {
  display: flex;
  align-items: center;
  gap: 8px;
}

select, input[type="number"] {
  flex: 1;
  height: 52px;
  padding: 0 16px;
  border-radius: var(--radius);
  background: var(--input-bg);
  color: var(--text-color);
  border: 1px solid var(--card-border);
  font-size: 1rem;
  font-family: inherit;
  transition: border-color 0.2s;
  appearance: none;
}

select {
  background-image: url("data:image/svg+xml,%3Csvg fill='gray' height='20' viewBox='0 0 24 24' width='20' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M7 10l5 5 5-5z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  background-size: 20px;
  cursor: pointer;
}

select:focus, input[type="number"]:focus {
  border-color: var(--accent-color);
  outline: none;
}

input[type="number"]::-webkit-outer-spin-button,
input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

input[type="number"] {
  -moz-appearance: textfield;
}

.file-wrapper {
  display: flex;
}

.file-wrapper.hidden {
  display: none;
}

.file-icon {
  width: 135px;
  min-width: 135px;
  height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 12px 16px;
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--card-border);
  border-radius: var(--radius);
  cursor: pointer;
  flex-shrink: 0;
  transition: all 0.25s ease;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-color);
  position: relative;
}

.file-icon.hidden {
  display: none;
}

.file-icon:hover {
  background: var(--accent-color);
  border-color: var(--accent-color);
}

.file-icon .icon {
  display: block;
  font-size: 1.1rem;
}

.file-icon .file-text {
  display: block;
  font-size: 0.9rem;
  font-weight: 600;
}

.file-icon .loader {
  display: block;
}

.hidden {
  display: none !important;
}

.loader {
  width: 20px;
  height: 20px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top: 2px solid var(--accent-color);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.urgent-toggle {
  width: 135px;
  min-width: 135px;
  padding: 12px 16px;
  height: 52px;
  background: rgba(255, 255, 255, 0.05);
  border: 1.5px solid rgba(255, 255, 255, 0.2);
  color: rgba(255, 255, 255, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  font-size: 0.9rem;
  font-weight: 700;
  transition: all 0.25s ease;
  flex-shrink: 0;
  border-radius: var(--radius);
  cursor: pointer;
  font-family: 'Montserrat', sans-serif;
}

.urgent-toggle:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: rgba(255, 255, 255, 0.3);
  color: #fff;
}

.urgent-toggle.active {
  background: linear-gradient(135deg, #ff3b30 0%, #d63031 100%);
  border-color: #ff3b30;
  color: #fff;
  box-shadow: 0 4px 12px rgba(255, 59, 48, 0.4);
}

.urgent-toggle.active:hover {
  background: linear-gradient(135deg, #ff3b30 0%, #d63031 100%);
  filter: brightness(1.1);
}

.urgent-toggle .urgent-icon {
  font-size: 1.1rem;
  display: inline-block;
}

.urgent-toggle.active .urgent-icon {
  animation: pulse 0.6s ease;
}

@keyframes pulse {
  0%, 100% { transform: scale(1); }
  50% { transform: scale(1.5); }
}

button:not(.urgent-toggle) {
  width: 100%;
  padding: 14px 24px;
  font-family: 'Montserrat', sans-serif;
  font-size: 1.05rem;
  font-weight: 700;
  border-radius: var(--radius);
  background: var(--button-bg);
  color: var(--text-color);
  border: none;
  cursor: pointer;
  transition: all 0.25s ease;
  position: relative;
  overflow: hidden;
}

button:not(.urgent-toggle)::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(255,255,255,0.3), transparent);
  transition: left 0.6s ease;
}

button:not(.urgent-toggle):hover::before {
  left: 100%;
}

button:not(.urgent-toggle):hover {
  filter: brightness(1.1);
  transform: translateY(-2px) scale(1.01);
  box-shadow: 0 6px 20px rgba(0, 0, 0, 0.3);
}

button:not(.urgent-toggle):active {
  transform: scale(0.99);
}

.result-container {
  background: rgba(139, 92, 246, 0.1);
  border: 1px solid rgba(139, 92, 246, 0.3);
  border-radius: var(--radius);
  padding: 20px;
  min-height: 320px;
  display: flex;
  align-items: flex-start;
  justify-content: center;
  flex-direction: column;
}

.result-content {
  width: 100%;
}

.result-row {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 10px;
  font-size: 0.95rem;
  flex-wrap: wrap;
  animation: fadeIn 0.5s ease;
}

.result-row:last-child {
  margin-bottom: 0;
}

.result-row .icon {
  font-size: 1.3rem;
  flex-shrink: 0;
}

.result-row .label {
  font-weight: 600;
  opacity: 0.8;
  flex-shrink: 0;
}

.result-row .value {
  font-weight: 700;
  color: var(--accent-light);
}

.spinner {
  width: 24px;
  height: 24px;
  border: 3px solid rgba(255, 255, 255, 0.3);
  border-top-color: var(--accent-color);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
  margin: 0 auto;
}

.tooltip-info {
  font-size: 0.85rem;
  line-height: 1.6;
  color: var(--text-color);
  opacity: 0.7;
  text-align: left;
  animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(-5px);
  }
  to {
    opacity: 0.7;
    transform: translateY(0);
  }
}

.tooltip-info.fade-out {
  animation: fadeOut 0.3s ease forwards;
}

@keyframes fadeOut {
  from {
    opacity: 0.7;
    transform: translateY(0);
  }
  to {
    opacity: 0;
    transform: translateY(5px);
  }
}

footer {
  margin-top: 0;
  padding: 24px 32px;
  font-size: 14px;
  color: var(--text-color);
  opacity: 1;
  text-align: center;
  border-top: 1px solid rgba(255, 255, 255, 0.12);
}

@media (max-width: 768px) {
  .calculator-wrapper {
    background: transparent;
    backdrop-filter: none;
    border: none;
    border-radius: 0;
    box-shadow: none;
  }

  .calculator-header {
    padding: 24px;
    border-bottom: none;
  }

  .calculator-header .title {
    font-size: 1.4rem;
  }

  .calculator-body {
    padding: 24px;
  }

  .back-btn {
    top: 12px;
    left: 12px;
    padding: 10px 16px;
    font-size: 0.9rem;
  }

  footer {
    border-top: none;
  }

  select {
    flex: 1;
  }

  .urgent-toggle {
    width: 52px;
    min-width: 52px;
    padding: 0;
  }

  .urgent-toggle .urgent-text {
    display: none;
  }

  .urgent-toggle .urgent-icon {
    font-size: 1.3rem;
  }

  .file-wrapper {
    display: flex;
  }

  .file-icon {
    width: 52px;
    min-width: 52px;
    padding: 0;
  }

  .file-icon .file-text {
    display: none;
  }

  .file-icon .icon {
    font-size: 1.3rem;
  }
}

@media (max-width: 480px) {
  .calculator-header .title {
    font-size: 1.2rem;
  }

  .calculator-body {
    padding: 20px;
    gap: 16px;
  }

  select, input[type="number"] {
    font-size: 0.95rem;
  }

  button {
    font-size: 1rem;
    padding: 12px 20px;
  }

  .result-row {
    font-size: 0.9rem;
  }
}