/* ============================================
   Student Finance Tracker - Main Stylesheet
   Mobile-First Responsive Design
   Color Palette: #4C763B, #043915, #B0CE88
   ============================================ */

/* CSS Reset & Base Styles */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

:root {
  /* Color Palette - Light Theme */
  --color-primary: #4c763b;
  --color-primary-dark: #043915;
  --color-primary-light: #b0ce88;
  --color-background: #fafaf9;
  --color-surface: #ffffff;
  --color-text: #1c1917;
  --color-text-secondary: #57534e;
  --color-border: #e7e5e4;
  --color-error: #dc2626;
  --color-success: #16a34a;
  --color-warning: #ea580c;

  /* Typography */
  --font-sans: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI",
    sans-serif;
  --font-mono: "JetBrains Mono", "Courier New", monospace;

  /* Spacing */
  --space-xs: 0.25rem; /* 4px */
  --space-sm: 0.5rem; /* 8px */
  --space-md: 0.75rem; /* 12px */
  --space-lg: 1rem; /* 16px */
  --space-xl: 1.25rem; /* 20px */
  --space-2xl: 1.5rem; /* 24px */
  --space-3xl: 2rem; /* 32px */
  --space-4xl: 2.5rem; /* 40px */
  --space-5xl: 3rem; /* 48px */
  --space-6xl: 4rem; /* 64px */

  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;

  /* Shadows */
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1);

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-base: 200ms ease;
  --transition-slow: 300ms ease;
}

/* Dark Theme */
[data-theme="dark"] {
  --color-background: #0f0f0f;
  --color-surface: #1a1a1a;
  --color-text: #f5f5f5;
  --color-text-secondary: #a3a3a3;
  --color-border: #404040;
  --color-primary-light: #4a5d3a;
}

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

body {
  font-family: var(--font-sans);
  font-size: 1rem;
  line-height: 1.6;
  color: var(--color-text);
  background-color: var(--color-background);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Typography */
h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 600;
  line-height: 1.2;
  color: var(--color-text);
}

h1 {
  font-size: 1.875rem;
  font-weight: 700;
}

h2 {
  font-size: 1.5rem;
}

h3 {
  font-size: 1.25rem;
}

p {
  margin-bottom: var(--space-lg);
}

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

a:hover {
  color: var(--color-primary-dark);
  text-decoration: underline;
}

a:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* Screen Reader Only */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border-width: 0;
}

/* Skip Link */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--color-primary-dark);
  color: white;
  padding: var(--space-sm) var(--space-lg);
  z-index: 100;
  border-radius: 0 0 var(--radius-md) 0;
}

.skip-link:focus {
  top: 0;
}

/* Container */
.container {
  width: 100%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 var(--space-lg);
}

/* Header */
.header {
  background-color: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  position: sticky;
  top: 0;
  z-index: 50;
  box-shadow: var(--shadow-sm);
}

.header-content {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-lg) 0;
}

.logo {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  font-weight: 600;
  font-size: 1.125rem;
  color: var(--color-text);
}

.logo-text {
  display: none;
}

/* Navigation */
.nav {
  display: none;
}

.nav-list {
  display: flex;
  gap: var(--space-2xl);
  list-style: none;
}

.nav-link {
  color: var(--color-text-secondary);
  font-weight: 500;
  padding: var(--space-sm) 0;
  border-bottom: 2px solid transparent;
  transition: all var(--transition-fast);
}

.nav-link:hover {
  color: var(--color-primary);
  text-decoration: none;
}

.nav-link.active {
  color: var(--color-primary);
  border-bottom-color: var(--color-primary);
}

/* Header Actions */
.header-actions {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

/* Theme Toggle */
.theme-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
  border-radius: var(--radius-md);
  transition: background-color var(--transition-fast);
}

.theme-toggle:hover {
  background-color: var(--color-border);
}

.theme-icon {
  color: var(--color-text);
  transition: transform var(--transition-fast);
}

.theme-toggle:hover .theme-icon {
  transform: rotate(180deg);
}

/* Mobile Menu Toggle */
.mobile-menu-toggle {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0;
}

.hamburger {
  position: relative;
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: var(--transition-base);
}

.hamburger::before,
.hamburger::after {
  content: "";
  position: absolute;
  width: 24px;
  height: 2px;
  background-color: var(--color-text);
  transition: var(--transition-base);
}

.hamburger::before {
  top: -8px;
}

.hamburger::after {
  bottom: -8px;
}

/* Mobile menu active state */
.mobile-menu-toggle[aria-expanded="true"] .hamburger {
  background-color: transparent;
}

.mobile-menu-toggle[aria-expanded="true"] .hamburger::before {
  top: 0;
  transform: rotate(45deg);
}

.mobile-menu-toggle[aria-expanded="true"] .hamburger::after {
  bottom: 0;
  transform: rotate(-45deg);
}

/* Mobile navigation */
@media (max-width: 767px) {
  .nav {
    position: absolute;
    top: 100%;
    left: 0;
    right: 0;
    background-color: var(--color-surface);
    border-top: 1px solid var(--color-border);
    box-shadow: var(--shadow-md);
    transform: translateY(-100%);
    opacity: 0;
    visibility: hidden;
    transition: all var(--transition-base);
  }

  .nav.active {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
  }

  .nav-list {
    flex-direction: column;
    gap: 0;
    padding: var(--space-lg);
  }

  .nav-link {
    padding: var(--space-md) 0;
    border-bottom: 1px solid var(--color-border);
    text-align: center;
  }

  .nav-link:last-child {
    border-bottom: none;
  }

  .nav-link.active {
    border-bottom-color: var(--color-primary);
    background-color: var(--color-primary-light);
    color: var(--color-primary-dark);
  }
}

/* Main Content */
.main {
  flex: 1;
  padding: var(--space-3xl) 0;
}

.page-header {
  margin-bottom: var(--space-3xl);
}

.page-header h1 {
  margin-bottom: var(--space-sm);
}

.page-description {
  color: var(--color-text-secondary);
  font-size: 1.125rem;
  margin-bottom: 0;
}

/* Section Styles */
.section-title {
  margin-bottom: var(--space-2xl);
  color: var(--color-text);
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-2xl);
}

.view-all-link {
  color: var(--color-primary);
  font-weight: 500;
}

/* Budget Status */
.budget-status {
  margin-bottom: var(--space-4xl);
}

.budget-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  box-shadow: var(--shadow-sm);
}

.budget-info {
  display: flex;
  justify-content: space-between;
  margin-bottom: var(--space-2xl);
}

.budget-amount {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.budget-amount .label {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

.budget-amount .amount {
  font-size: 1.5rem;
  font-weight: 700;
  font-family: var(--font-mono);
  color: var(--color-text);
}

.progress-bar {
  width: 100%;
  height: 12px;
  background-color: var(--color-border);
  border-radius: var(--radius-xl);
  overflow: hidden;
  margin-bottom: var(--space-lg);
}

.progress-fill {
  height: 100%;
  background-color: var(--color-primary);
  transition: width var(--transition-slow),
    background-color var(--transition-slow);
  border-radius: var(--radius-xl);
}

.progress-fill.warning {
  background-color: var(--color-warning);
}

.progress-fill.danger {
  background-color: var(--color-error);
}

.budget-message {
  font-size: 0.875rem;
  padding: var(--space-sm) var(--space-lg);
  border-radius: var(--radius-md);
  text-align: center;
}

.budget-message.success {
  background-color: #dcfce7;
  color: #166534;
}

.budget-message.warning {
  background-color: #fed7aa;
  color: #9a3412;
}

.budget-message.danger {
  background-color: #fee2e2;
  color: #991b1b;
}

/* Stats Grid */
.stats-section {
  margin-bottom: var(--space-4xl);
}

.stats-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

.stat-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-2xl);
  display: flex;
  gap: var(--space-lg);
  box-shadow: var(--shadow-sm);
  transition: box-shadow var(--transition-base);
}

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

.stat-icon {
  width: 48px;
  height: 48px;
  background-color: var(--color-primary-light);
  border-radius: var(--radius-md);
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--color-primary-dark);
  flex-shrink: 0;
}

.stat-content {
  flex: 1;
}

.stat-label {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-xs);
}

.stat-value {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--color-text);
  font-family: var(--font-mono);
}

/* Transactions List */
.transactions-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.transaction-item {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-lg);
  display: flex;
  justify-content: space-between;
  align-items: center;
  transition: box-shadow var(--transition-base);
}

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

.transaction-info {
  flex: 1;
}

.transaction-description {
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

.transaction-meta {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
}

.transaction-amount {
  font-size: 1.25rem;
  font-weight: 700;
  font-family: var(--font-mono);
  color: var(--color-text);
}

/* Table Styles */
.table-controls {
  margin-bottom: var(--space-2xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-lg);
}

.search-box {
  flex: 1;
}

.search-input {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-family: var(--font-mono);
  transition: border-color var(--transition-fast);
}

.search-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(76, 118, 59, 0.1);
}

.help-text {
  display: block;
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin-top: var(--space-xs);
}

.error-message {
  display: block;
  font-size: 0.875rem;
  color: var(--color-error);
  margin-top: var(--space-xs);
}

.search-count {
  font-size: 0.875rem;
  color: var(--color-primary);
  margin-top: var(--space-xs);
}

.table-actions {
  display: flex;
  gap: var(--space-md);
  flex-wrap: wrap;
}

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

.transactions-table {
  width: 100%;
  border-collapse: collapse;
}

.transactions-table thead {
  background-color: var(--color-primary-light);
}

.transactions-table th {
  padding: var(--space-lg);
  text-align: left;
  font-weight: 600;
  color: var(--color-primary-dark);
  border-bottom: 2px solid var(--color-primary);
}

.transactions-table td {
  padding: var(--space-lg);
  border-bottom: 1px solid var(--color-border);
}

.transactions-table tbody tr:hover {
  background-color: var(--color-background);
}

.sort-btn {
  background: none;
  border: none;
  color: inherit;
  font: inherit;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  padding: 0;
}

.sort-btn:hover {
  color: var(--color-primary-dark);
}

.sort-icon {
  font-size: 0.875rem;
}

.empty-state {
  text-align: center;
  padding: var(--space-4xl);
  color: var(--color-text-secondary);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-md) var(--space-xl);
  font-size: 1rem;
  font-weight: 500;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
  font-family: var(--font-sans);
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}

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

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

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

.btn-secondary:hover {
  background-color: var(--color-background);
}

.btn-danger {
  background-color: var(--color-error);
  color: white;
}

.btn-danger:hover {
  background-color: #b91c1c;
}

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

/* Forms */
.form-container {
  max-width: 600px;
  margin: 0 auto;
}

.transaction-form,
.settings-form {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-3xl);
  box-shadow: var(--shadow-sm);
}

.form-group {
  margin-bottom: var(--space-2xl);
}

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

.required {
  color: var(--color-error);
}

.form-input,
.form-select {
  width: 100%;
  padding: var(--space-md) var(--space-lg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: 1rem;
  font-family: var(--font-sans);
  transition: border-color var(--transition-fast);
}

.form-input:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(76, 118, 59, 0.1);
}

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

.form-actions {
  display: flex;
  gap: var(--space-md);
  justify-content: flex-end;
  margin-top: var(--space-3xl);
}

.form-status {
  margin-top: var(--space-lg);
  padding: var(--space-lg);
  border-radius: var(--radius-md);
  text-align: center;
}

.form-status.success {
  background-color: #dcfce7;
  color: #166534;
}

.form-status.error {
  background-color: #fee2e2;
  color: #991b1b;
}

/* Settings Page */
.settings-section {
  margin-bottom: var(--space-4xl);
}

.settings-card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-3xl);
  box-shadow: var(--shadow-sm);
}

.currency-converter {
  margin-top: var(--space-3xl);
  padding-top: var(--space-3xl);
  border-top: 1px solid var(--color-border);
}

.converter-title {
  margin-bottom: var(--space-2xl);
}

.converter-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
  margin-bottom: var(--space-lg);
}

.converter-result {
  padding: var(--space-lg);
  background-color: var(--color-primary-light);
  border-radius: var(--radius-md);
  text-align: center;
  font-size: 1.25rem;
  font-weight: 600;
  font-family: var(--font-mono);
  color: var(--color-primary-dark);
}

.data-actions {
  display: flex;
  flex-direction: column;
  gap: var(--space-2xl);
}

.data-action-item {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: var(--space-lg);
  padding-bottom: var(--space-2xl);
  border-bottom: 1px solid var(--color-border);
}

.data-action-item:last-child {
  border-bottom: none;
  padding-bottom: 0;
}

.data-action-item.danger {
  border-color: var(--color-error);
}

.action-title {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: var(--space-xs);
}

.action-description {
  font-size: 0.875rem;
  color: var(--color-text-secondary);
  margin: 0;
}

/* About Page */
.about-content {
  max-width: 800px;
  margin: 0 auto;
}

.about-section {
  margin-bottom: var(--space-4xl);
}

.about-section h2 {
  margin-bottom: var(--space-lg);
}

.about-section h3 {
  margin-top: var(--space-2xl);
  margin-bottom: var(--space-lg);
}

.feature-list,
.tech-list,
.validation-list,
.accessibility-list {
  list-style: none;
  padding-left: 0;
}

.feature-list li,
.tech-list li,
.validation-list li,
.accessibility-list li {
  padding-left: var(--space-2xl);
  margin-bottom: var(--space-md);
  position: relative;
}

.feature-list li::before,
.tech-list li::before,
.validation-list li::before,
.accessibility-list li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-primary);
  font-weight: 700;
}

.keyboard-shortcuts {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--space-lg);
}

.shortcut-item {
  display: flex;
  align-items: center;
  gap: var(--space-lg);
  padding: var(--space-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
}

kbd {
  padding: var(--space-xs) var(--space-md);
  background-color: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: var(--font-mono);
  font-size: 0.875rem;
  box-shadow: 0 2px 0 var(--color-border);
}

.code-block {
  background-color: var(--color-background);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: var(--space-2xl);
  overflow-x: auto;
}

.code-block code {
  font-family: var(--font-mono);
  font-size: 0.875rem;
  line-height: 1.6;
}

/* Modal */
.modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-lg);
}

.modal[hidden] {
  display: none;
}

.modal-overlay {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background-color: rgba(0, 0, 0, 0.5);
}

.modal-content {
  position: relative;
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-3xl);
  max-width: 500px;
  width: 100%;
  box-shadow: var(--shadow-lg);
}

.modal-content h2 {
  margin-bottom: var(--space-lg);
}

.modal-content p {
  margin-bottom: var(--space-2xl);
}

.modal-actions {
  display: flex;
  gap: var(--space-md);
  justify-content: flex-end;
}

/* Footer */
.footer {
  background-color: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: var(--space-3xl) 0;
  margin-top: auto;
}

.footer p {
  text-align: center;
  color: var(--color-text-secondary);
  margin: 0;
}

/* Highlight for search results */
.highlight {
  background-color: #fef08a;
  padding: 2px 4px;
  border-radius: 2px;
}

/* Tablet Styles (768px and up) */
@media (min-width: 768px) {
  h1 {
    font-size: 2.25rem;
  }

  .logo-text {
    display: inline;
  }

  .mobile-menu-toggle {
    display: none;
  }

  .nav {
    display: block;
  }

  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }

  .table-controls {
    flex-direction: row;
    align-items: flex-start;
  }

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

  .keyboard-shortcuts {
    grid-template-columns: repeat(2, 1fr);
  }

  .form-actions {
    justify-content: flex-end;
  }
}

/* Desktop Styles (1024px and up) */
@media (min-width: 1024px) {
  h1 {
    font-size: 2.5rem;
  }

  .stats-grid {
    grid-template-columns: repeat(4, 1fr);
  }

  .container {
    padding: 0 var(--space-2xl);
  }
}

/* Print Styles */
@media print {
  .header,
  .footer,
  .btn,
  .mobile-menu-toggle,
  .table-actions,
  .form-actions {
    display: none;
  }

  body {
    background: white;
  }

  .main {
    padding: 0;
  }
}