/* =========================================
   Calculator V2 - Fully Responsive Design
   Version: 2.0
   Updated: 2025-12-21
   ========================================= */

/* === CSS Variables === */
:root {
  --calc-primary: #3b82f6;
  --calc-primary-hover: #2563eb;
  --calc-primary-light: rgba(59, 130, 246, 0.1);
  --calc-surface: #ffffff;
  --calc-surface-alt: #f8fafc;
  --calc-border: #e2e8f0;
  --calc-text: #1e293b;
  --calc-text-secondary: #64748b;
  --calc-text-muted: #94a3b8;
  --calc-success: #10b981;
  --calc-success-light: rgba(16, 185, 129, 0.1);
  --calc-warning: #f59e0b;
  --calc-warning-light: rgba(245, 158, 11, 0.1);
  --calc-error: #ef4444;
  --calc-radius: 16px;
  --calc-radius-sm: 10px;
  --calc-radius-xs: 6px;
  --calc-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --calc-shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
}

.dark {
  --calc-surface: #1e293b;
  --calc-surface-alt: #0f172a;
  --calc-border: #334155;
  --calc-text: #f1f5f9;
  --calc-text-secondary: #cbd5e1;
  --calc-text-muted: #64748b;
  --calc-primary-light: rgba(59, 130, 246, 0.15);
  --calc-success-light: rgba(16, 185, 129, 0.15);
  --calc-warning-light: rgba(245, 158, 11, 0.15);
}

/* === Base Reset === */
.calc-app * {
  box-sizing: border-box;
}

/* === Main Container - RESPONSIVE === */
.calc-container {
  width: 100%;
  margin: 0 auto;
  padding: 0 1rem;
}

/* Mobile first: max 480px */
@media (min-width: 480px) {
  .calc-container {
    max-width: 540px;
    padding: 0 1.5rem;
  }
}

/* Tablet: 768px+ */
@media (min-width: 768px) {
  .calc-container {
    max-width: 720px;
    padding: 0 2rem;
  }
}

/* Desktop: 1024px+ */
@media (min-width: 1024px) {
  .calc-container {
    max-width: 900px;
  }
}

/* Large desktop: 1280px+ */
@media (min-width: 1280px) {
  .calc-container {
    max-width: 1000px;
  }
}

/* === Header === */
.calc-header {
  position: sticky;
  top: 0;
  z-index: 50;
  background: var(--calc-surface);
  border-bottom: 1px solid var(--calc-border);
  padding: 0.75rem 0;
}

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

.calc-logo {
  height: 36px;
  width: auto;
}

@media (min-width: 768px) {
  .calc-logo {
    height: 42px;
  }
}

.calc-header-actions {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

@media (min-width: 768px) {
  .calc-header-actions {
    gap: 0.75rem;
  }
}

.calc-icon-btn {
  width: 40px;
  height: 40px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--calc-surface-alt);
  border: 1px solid var(--calc-border);
  border-radius: var(--calc-radius-sm);
  color: var(--calc-text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.calc-icon-btn:hover {
  background: var(--calc-primary-light);
  border-color: var(--calc-primary);
  color: var(--calc-primary);
}

.calc-lang-switcher {
  display: flex;
  background: var(--calc-surface-alt);
  border: 1px solid var(--calc-border);
  border-radius: var(--calc-radius-sm);
  overflow: hidden;
}

.calc-lang-btn {
  padding: 0.5rem 0.75rem;
  background: transparent;
  border: none;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--calc-text-secondary);
  cursor: pointer;
  transition: all 0.15s;
  text-decoration: none;
}

@media (min-width: 768px) {
  .calc-lang-btn {
    padding: 0.5rem 1rem;
    font-size: 0.8125rem;
  }
}

.calc-lang-btn.active,
.calc-lang-btn:hover {
  background: var(--calc-primary);
  color: white;
}

/* === Page Title === */
.calc-page-title {
  text-align: center;
  padding: 1.5rem 0 1rem;
}

@media (min-width: 768px) {
  .calc-page-title {
    padding: 2rem 0 1.5rem;
  }
}

.calc-title-icon {
  font-size: 2.5rem;
  margin-bottom: 0.5rem;
}

@media (min-width: 768px) {
  .calc-title-icon {
    font-size: 3rem;
  }
}

.calc-title-text {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--calc-text);
  margin: 0;
  line-height: 1.3;
}

@media (min-width: 768px) {
  .calc-title-text {
    font-size: 1.875rem;
  }
}

@media (min-width: 1024px) {
  .calc-title-text {
    font-size: 2.25rem;
  }
}

/* === Card === */
.calc-card {
  background: var(--calc-surface);
  border: 1px solid var(--calc-border);
  border-radius: var(--calc-radius);
  padding: 1.25rem;
  margin-bottom: 1rem;
  box-shadow: var(--calc-shadow);
}

@media (min-width: 768px) {
  .calc-card {
    padding: 2rem;
    margin-bottom: 1.5rem;
    border-radius: 20px;
  }
}

@media (min-width: 1024px) {
  .calc-card {
    padding: 2.5rem;
    margin-bottom: 2rem;
  }
}

/* === Form Group === */
.calc-form-group {
  margin-bottom: 1rem;
}

@media (min-width: 768px) {
  .calc-form-group {
    margin-bottom: 1.5rem;
  }
}

.calc-form-group:last-child {
  margin-bottom: 0;
}

/* === Labels === */
.calc-label {
  display: flex;
  align-items: center;
  gap: 0.375rem;
  font-size: 0.75rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--calc-text-muted);
  margin-bottom: 0.5rem;
}

@media (min-width: 768px) {
  .calc-label {
    font-size: 0.8125rem;
    margin-bottom: 0.625rem;
  }
}

.calc-label-icon {
  font-size: 0.875rem;
}

@media (min-width: 768px) {
  .calc-label-icon {
    font-size: 1rem;
  }
}

/* === Inputs & Selects === */
.calc-input,
.calc-select {
  width: 100%;
  padding: 0.875rem 1rem;
  background: var(--calc-surface-alt);
  border: 2px solid var(--calc-border);
  border-radius: var(--calc-radius-sm);
  font-size: 1rem;
  color: var(--calc-text);
  transition: all 0.2s;
  -webkit-appearance: none;
  appearance: none;
}

@media (min-width: 768px) {

  .calc-input,
  .calc-select {
    padding: 1rem 1.25rem;
    font-size: 1.0625rem;
    border-radius: var(--calc-radius);
  }
}

.calc-input:focus,
.calc-select:focus {
  outline: none;
  border-color: var(--calc-primary);
  background: var(--calc-surface);
  box-shadow: 0 0 0 4px var(--calc-primary-light);
}

.calc-input::placeholder {
  color: var(--calc-text-muted);
}

.calc-input:disabled,
.calc-select:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

/* Select with custom arrow */
.calc-select {
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%2394a3b8'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'%3E%3C/path%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 1rem center;
  background-size: 1.25rem;
  padding-right: 3rem;
}

/* === Row Grid - RESPONSIVE === */
.calc-row {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1rem;
}

@media (min-width: 640px) {
  .calc-row {
    grid-template-columns: repeat(2, 1fr);
    gap: 1.25rem;
  }
}

@media (min-width: 768px) {
  .calc-row {
    gap: 1.5rem;
  }
}

.calc-row-3 {
  grid-template-columns: repeat(3, 1fr);
}

/* === Info Hint === */
.calc-hint {
  font-size: 0.75rem;
  color: var(--calc-text-muted);
  margin-top: 0.375rem;
}

@media (min-width: 768px) {
  .calc-hint {
    font-size: 0.8125rem;
    margin-top: 0.5rem;
  }
}

.calc-hint a {
  color: var(--calc-primary);
  text-decoration: none;
}

.calc-hint a:hover {
  text-decoration: underline;
}

/* === Error Message === */
.calc-error {
  display: none;
  font-size: 0.75rem;
  color: var(--calc-error);
  margin-top: 0.375rem;
}

.calc-error.show {
  display: block;
}

/* === RTL Support === */
[dir="rtl"] .calc-select {
  background-position: left 1rem center;
  padding-left: 3rem;
  padding-right: 1rem;
}

[dir="rtl"] .calc-input-group {
  flex-direction: row-reverse;
}

/* === Loading State === */
.calc-loading {
  position: relative;
  pointer-events: none;
}

.calc-loading::after {
  content: '';
  position: absolute;
  top: 50%;
  left: 50%;
  width: 20px;
  height: 20px;
  margin: -10px 0 0 -10px;
  border: 2px solid transparent;
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

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

/* === Animations === */
@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}