/* =========================================
   投資工具網站 - 設計系統
   風格：淺色、簡潔、商業感
   ========================================= */

/* ===== CSS Variables ===== */
:root {
  /* 主色調 - 淺綠色商業風格 */
  --color-primary: #10B981;
  --color-primary-hover: #059669;
  --color-primary-light: #D1FAE5;
  
  /* 中性色 */
  --color-bg: #FAFBFC;
  --color-surface: #FFFFFF;
  --color-surface-elevated: #FFFFFF;
  --color-border: #E5E7EB;
  --color-border-light: #F3F4F6;
  
  /* 文字色 */
  --color-text-primary: #111827;
  --color-text-secondary: #6B7280;
  --color-text-tertiary: #9CA3AF;
  --color-text-inverse: #FFFFFF;
  
  /* 功能色 */
  --color-success: #10B981;
  --color-success-light: #D1FAE5;
  --color-warning: #F59E0B;
  --color-warning-light: #FEF3C7;
  --color-error: #EF4444;
  --color-error-light: #FEE2E2;
  --color-info: #3B82F6;
  --color-info-light: #DBEAFE;
  
  /* 陰影 */
  --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 -1px rgba(0, 0, 0, 0.06);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -2px rgba(0, 0, 0, 0.05);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  /* 間距 */
  --spacing-xs: 0.25rem;
  --spacing-sm: 0.5rem;
  --spacing-md: 1rem;
  --spacing-lg: 1.5rem;
  --spacing-xl: 2rem;
  --spacing-2xl: 3rem;
  --spacing-3xl: 4rem;
  
  /* 圓角 */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-full: 9999px;
  
  /* 字體 */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-display: 'Outfit', var(--font-sans);
  
  /* 字體大小 */
  --text-xs: 0.75rem;
  --text-sm: 0.875rem;
  --text-base: 1rem;
  --text-lg: 1.125rem;
  --text-xl: 1.25rem;
  --text-2xl: 1.5rem;
  --text-3xl: 1.875rem;
  --text-4xl: 2.25rem;
  
  /* 行高 */
  --leading-tight: 1.25;
  --leading-normal: 1.5;
  --leading-relaxed: 1.625;
  
  /* 過渡效果 */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;
  
  /* 容器寬度 */
  --container-sm: 640px;
  --container-md: 768px;
  --container-lg: 1024px;
  --container-xl: 1200px;
}

/* ===== Reset ===== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 16px;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  line-height: var(--leading-normal);
  color: var(--color-text-primary);
  background-color: var(--color-bg);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* ===== Typography ===== */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-display);
  font-weight: 600;
  line-height: var(--leading-tight);
  color: var(--color-text-primary);
}

h1 {
  font-size: var(--text-4xl);
  font-weight: 700;
  letter-spacing: -0.02em;
}

h2 {
  font-size: var(--text-2xl);
  letter-spacing: -0.01em;
}

h3 {
  font-size: var(--text-xl);
}

p {
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
}

a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-fast);
}

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

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: var(--container-xl);
  margin: 0 auto;
  padding: 0 var(--spacing-lg);
}

main {
  flex: 1;
  padding: var(--spacing-2xl) 0;
}

/* ===== Navigation ===== */
.nav {
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.nav-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) var(--spacing-lg);
  max-width: var(--container-xl);
  margin: 0 auto;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
  font-family: var(--font-display);
  font-size: var(--text-xl);
  font-weight: 700;
  color: var(--color-text-primary);
  text-decoration: none;
}

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

.nav-logo-icon {
  width: 32px;
  height: 32px;
  background: linear-gradient(135deg, var(--color-primary), var(--color-primary-hover));
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: var(--text-lg);
}

.nav-links {
  display: flex;
  align-items: center;
  gap: var(--spacing-xl);
  list-style: none;
}

.nav-link {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
  position: relative;
}

.nav-link:hover,
.nav-link.active {
  color: var(--color-primary);
}

.nav-link.active::after {
  content: '';
  position: absolute;
  bottom: -6px;
  left: 0;
  right: 0;
  height: 2px;
  background: var(--color-primary);
  border-radius: var(--radius-full);
}

.nav-mobile-toggle {
  display: none;
  flex-direction: column;
  gap: 4px;
  background: none;
  border: none;
  cursor: pointer;
  padding: var(--spacing-sm);
}

.nav-mobile-toggle span {
  width: 20px;
  height: 2px;
  background: var(--color-text-primary);
  border-radius: var(--radius-full);
  transition: all var(--transition-fast);
}

/* ===== Cards ===== */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-sm);
  transition: all var(--transition-base);
}

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

.card-title {
  font-size: var(--text-lg);
  margin-bottom: var(--spacing-sm);
}

.card-description {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-md);
}

/* Tool Card */
.tool-card {
  display: flex;
  flex-direction: column;
  text-decoration: none;
  cursor: pointer;
}

.tool-card:hover {
  border-color: var(--color-primary);
  transform: translateY(-2px);
}

.tool-card-icon {
  width: 48px;
  height: 48px;
  background: var(--color-primary-light);
  border-radius: var(--radius-lg);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-2xl);
  margin-bottom: var(--spacing-md);
  transition: all var(--transition-base);
}

.tool-card:hover .tool-card-icon {
  background: var(--color-primary);
  color: white;
}

.tool-card-arrow {
  margin-top: auto;
  display: flex;
  align-items: center;
  gap: var(--spacing-xs);
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-primary);
}

/* ===== Forms ===== */
.form-group {
  margin-bottom: var(--spacing-lg);
}

.form-label {
  display: block;
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-sm);
}

.form-label-hint {
  font-weight: 400;
  color: var(--color-text-tertiary);
  margin-left: var(--spacing-xs);
}

.form-input,
.form-select {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: var(--text-base);
  font-family: inherit;
  color: var(--color-text-primary);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
}

.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.form-input::placeholder {
  color: var(--color-text-tertiary);
}

.form-input.error {
  border-color: var(--color-error);
}

.form-input.error:focus {
  box-shadow: 0 0 0 3px var(--color-error-light);
}

.form-error {
  font-size: var(--text-sm);
  color: var(--color-error);
  margin-top: var(--spacing-xs);
  display: none;
}

.form-input.error + .form-error {
  display: block;
}

.form-row {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: var(--spacing-lg);
}

/* Input with suffix */
.input-wrapper {
  position: relative;
}

.input-suffix {
  position: absolute;
  right: var(--spacing-md);
  top: 50%;
  transform: translateY(-50%);
  font-size: var(--text-sm);
  color: var(--color-text-tertiary);
  pointer-events: none;
}

.form-input.has-suffix {
  padding-right: 3rem;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-sm);
  padding: var(--spacing-sm) var(--spacing-lg);
  font-size: var(--text-sm);
  font-weight: 500;
  font-family: inherit;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}

.btn-primary:hover:not(:disabled) {
  background: var(--color-primary-hover);
}

.btn-secondary {
  background: var(--color-bg);
  color: var(--color-text-primary);
  border: 1px solid var(--color-border);
}

.btn-secondary:hover:not(:disabled) {
  background: var(--color-border-light);
  border-color: var(--color-border);
}

.btn-outline {
  background: transparent;
  color: var(--color-primary);
  border: 1px solid var(--color-primary);
}

.btn-outline:hover:not(:disabled) {
  background: var(--color-primary-light);
}

.btn-ghost {
  background: transparent;
  color: var(--color-text-secondary);
}

.btn-ghost:hover:not(:disabled) {
  background: var(--color-bg);
  color: var(--color-text-primary);
}

.btn-lg {
  padding: var(--spacing-md) var(--spacing-xl);
  font-size: var(--text-base);
}

.btn-sm {
  padding: var(--spacing-xs) var(--spacing-md);
  font-size: var(--text-xs);
}

.btn-icon {
  width: 36px;
  height: 36px;
  padding: 0;
  border-radius: var(--radius-md);
}

.btn-group {
  display: flex;
  gap: var(--spacing-sm);
}

/* ===== Result Card ===== */
.result-card {
  background: linear-gradient(135deg, #F0FDF4 0%, #ECFDF5 100%);
  border: 1px solid var(--color-primary-light);
  border-radius: var(--radius-xl);
  padding: var(--spacing-xl);
}

.result-title {
  font-size: var(--text-sm);
  font-weight: 500;
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xs);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.result-value {
  font-family: var(--font-display);
  font-size: var(--text-3xl);
  font-weight: 700;
  color: var(--color-primary);
}

.result-unit {
  font-size: var(--text-lg);
  font-weight: 400;
  color: var(--color-text-secondary);
  margin-left: var(--spacing-xs);
}

.result-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
  gap: var(--spacing-lg);
  margin-top: var(--spacing-lg);
}

.result-item {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
}

.result-item-label {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin-bottom: var(--spacing-xs);
}

.result-item-value {
  font-size: var(--text-xl);
  font-weight: 600;
  color: var(--color-text-primary);
}

/* ===== Section ===== */
.section {
  margin-bottom: var(--spacing-3xl);
}

.section-title {
  margin-bottom: var(--spacing-lg);
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.section-icon {
  width: 28px;
  height: 28px;
  background: var(--color-primary-light);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-sm);
}

/* ===== Steps ===== */
.steps {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.step {
  display: flex;
  gap: var(--spacing-md);
}

.step-number {
  width: 32px;
  height: 32px;
  background: var(--color-primary);
  color: white;
  border-radius: var(--radius-full);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-sm);
  font-weight: 600;
  flex-shrink: 0;
}

.step-content {
  flex: 1;
  padding-top: var(--spacing-xs);
}

.step-title {
  font-weight: 600;
  color: var(--color-text-primary);
  margin-bottom: var(--spacing-xs);
}

.step-description {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  margin: 0;
}

/* ===== FAQ ===== */
.faq-list {
  display: flex;
  flex-direction: column;
  gap: var(--spacing-md);
}

.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  overflow: hidden;
}

.faq-question {
  width: 100%;
  padding: var(--spacing-md) var(--spacing-lg);
  background: var(--color-surface);
  border: none;
  text-align: left;
  font-size: var(--text-base);
  font-weight: 500;
  color: var(--color-text-primary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--spacing-md);
  font-family: inherit;
  transition: background var(--transition-fast);
}

.faq-question:hover {
  background: var(--color-bg);
}

.faq-icon {
  font-size: var(--text-lg);
  color: var(--color-text-tertiary);
  transition: transform var(--transition-base);
}

.faq-item.active .faq-icon {
  transform: rotate(45deg);
}

.faq-answer {
  padding: 0 var(--spacing-lg);
  max-height: 0;
  overflow: hidden;
  transition: all var(--transition-base);
}

.faq-item.active .faq-answer {
  padding: var(--spacing-md) var(--spacing-lg);
  max-height: 500px;
}

.faq-answer p {
  margin: 0;
  font-size: var(--text-sm);
}

/* ===== Related Tools ===== */
.related-tools {
  margin-top: var(--spacing-3xl);
  padding-top: var(--spacing-2xl);
  border-top: 1px solid var(--color-border);
}

.related-tools-title {
  font-size: var(--text-lg);
  margin-bottom: var(--spacing-lg);
}

.related-tools-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: var(--spacing-md);
}

.related-tool-link {
  display: flex;
  align-items: center;
  gap: var(--spacing-md);
  padding: var(--spacing-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  text-decoration: none;
  transition: all var(--transition-fast);
}

.related-tool-link:hover {
  border-color: var(--color-primary);
  background: var(--color-primary-light);
}

.related-tool-icon {
  width: 40px;
  height: 40px;
  background: var(--color-bg);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--text-lg);
}

.related-tool-name {
  font-weight: 500;
  color: var(--color-text-primary);
}

/* ===== Footer ===== */
.footer {
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--spacing-2xl) 0;
  margin-top: auto;
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: var(--spacing-lg);
}

.footer-links {
  display: flex;
  gap: var(--spacing-xl);
  list-style: none;
}

.footer-link {
  font-size: var(--text-sm);
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

.footer-link:hover {
  color: var(--color-primary);
}

.footer-copyright {
  font-size: var(--text-sm);
  color: var(--color-text-tertiary);
}

/* ===== Hero ===== */
.hero {
  text-align: center;
  padding: var(--spacing-3xl) 0;
}

.hero-title {
  font-size: clamp(2rem, 5vw, 3rem);
  margin-bottom: var(--spacing-md);
}

.hero-subtitle {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  max-width: 600px;
  margin: 0 auto;
}

/* ===== Tool Grid ===== */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--spacing-lg);
  margin-top: var(--spacing-2xl);
}

/* ===== Page Header ===== */
.page-header {
  margin-bottom: var(--spacing-2xl);
}

.page-header-title {
  margin-bottom: var(--spacing-sm);
}

.page-header-description {
  font-size: var(--text-lg);
  color: var(--color-text-secondary);
  max-width: 700px;
}

/* ===== Calculator Layout ===== */
.calculator-layout {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: var(--spacing-xl);
  align-items: start;
}

.calculator-input-card {
  position: sticky;
  top: calc(60px + var(--spacing-lg));
}

/* ===== Disclaimer ===== */
.disclaimer {
  background: var(--color-warning-light);
  border: 1px solid #FCD34D;
  border-radius: var(--radius-lg);
  padding: var(--spacing-md);
  margin-top: var(--spacing-lg);
}

.disclaimer-icon {
  margin-right: var(--spacing-sm);
}

.disclaimer-text {
  font-size: var(--text-sm);
  color: #92400E;
  margin: 0;
}

/* ===== Toast ===== */
.toast-container {
  position: fixed;
  bottom: var(--spacing-xl);
  right: var(--spacing-xl);
  z-index: 1000;
  display: flex;
  flex-direction: column;
  gap: var(--spacing-sm);
}

.toast {
  background: var(--color-text-primary);
  color: white;
  padding: var(--spacing-md) var(--spacing-lg);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  font-size: var(--text-sm);
  animation: slideIn 0.3s ease, fadeOut 0.3s ease 2.7s;
}

@keyframes slideIn {
  from {
    transform: translateX(100%);
    opacity: 0;
  }
  to {
    transform: translateX(0);
    opacity: 1;
  }
}

@keyframes fadeOut {
  to {
    opacity: 0;
  }
}

/* ===== Static Page ===== */
.static-page {
  max-width: 800px;
  margin: 0 auto;
}

.static-page h2 {
  margin-top: var(--spacing-2xl);
  margin-bottom: var(--spacing-md);
}

.static-page p {
  margin-bottom: var(--spacing-md);
}

.static-page ul {
  padding-left: var(--spacing-xl);
  margin-bottom: var(--spacing-md);
}

.static-page li {
  margin-bottom: var(--spacing-sm);
  color: var(--color-text-secondary);
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
  .calculator-layout {
    grid-template-columns: 1fr;
  }
  
  .calculator-input-card {
    position: static;
  }
}

@media (max-width: 768px) {
  :root {
    --text-4xl: 1.875rem;
    --text-3xl: 1.5rem;
  }
  
  .nav-links {
    display: none;
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background: var(--color-surface);
    border-bottom: 1px solid var(--color-border);
    flex-direction: column;
    padding: var(--spacing-md);
    gap: var(--spacing-md);
  }
  
  .nav-links.active {
    display: flex;
  }
  
  .nav-mobile-toggle {
    display: flex;
  }
  
  .form-row {
    grid-template-columns: 1fr;
  }
  
  .footer-content {
    flex-direction: column;
    text-align: center;
  }
  
  .footer-links {
    flex-wrap: wrap;
    justify-content: center;
  }
  
  .result-grid {
    grid-template-columns: 1fr;
  }
  
  .tool-grid {
    grid-template-columns: 1fr;
  }
  
  .related-tools-grid {
    grid-template-columns: 1fr;
  }
}

/* ===== Utilities ===== */
.text-center { text-align: center; }
.text-right { text-align: right; }
.font-bold { font-weight: 700; }
.text-primary { color: var(--color-primary); }
.text-secondary { color: var(--color-text-secondary); }
.text-sm { font-size: var(--text-sm); }
.mt-sm { margin-top: var(--spacing-sm); }
.mt-md { margin-top: var(--spacing-md); }
.mt-lg { margin-top: var(--spacing-lg); }
.mb-sm { margin-bottom: var(--spacing-sm); }
.mb-md { margin-bottom: var(--spacing-md); }
.mb-lg { margin-bottom: var(--spacing-lg); }
.hidden { display: none !important; }
.flex { display: flex; }
.items-center { align-items: center; }
.justify-between { justify-content: space-between; }
.gap-sm { gap: var(--spacing-sm); }
.gap-md { gap: var(--spacing-md); }