/* ============================================
   CSS RESET & BASE STYLES
   ============================================ */

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

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

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;
  line-height: 1.6;
  color: #333;
  background-color: #fff;
  margin: 0;
  padding: 0;
}

/* ============================================
   LAYOUT & CONTAINER
   ============================================ */

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
}

/* ============================================
   TYPOGRAPHY
   ============================================ */

h1, h2, h3, h4, h5, h6 {
  margin-bottom: 1rem;
  font-weight: 600;
  line-height: 1.2;
}

h1 {
  font-size: 2.5rem;
}

h2 {
  font-size: 2rem;
}

h3 {
  font-size: 1.5rem;
}

p {
  margin-bottom: 1rem;
}

a {
  color: #0056ff;
  text-decoration: none;
  transition: color 0.2s ease;
}

a:hover {
  color: #003ad6;
}

/* ============================================
   HERO SECTION
   ============================================ */

.hero-section {
  text-align: center;
  padding: 4rem 2rem;
  background: linear-gradient(135deg, #4a9eff 0%, #0056ff 100%);
  color: white;
  margin-bottom: 3rem;
  border-radius: 8px;
}

.hero-title {
  font-size: 3rem;
  font-weight: 700;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, #fff 0%, #e0e0e0 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero-subtitle {
  font-size: 1.25rem;
  max-width: 800px;
  margin: 0 auto;
  opacity: 0.95;
}

/* ============================================
   BUTTONS
   ============================================ */

.btn {
  display: inline-block;
  padding: 12px 24px;
  font-size: 1rem;
  font-weight: 600;
  text-align: center;
  border: 2px solid transparent;
  border-radius: 8px;
  cursor: pointer;
  transition: all 0.2s ease;
  text-decoration: none;
}

.btn-primary {
  background-color: #0056ff;
  color: white;
  border-color: #0056ff;
}

.btn-primary:hover {
  background-color: #003ad6;
  border-color: #003ad6;
  color: white;
}

.btn-secondary {
  background-color: transparent;
  color: #0056ff;
  border-color: #0056ff;
}

.btn-secondary:hover {
  background-color: #0056ff;
  color: white;
}

/* ============================================
   SECTIONS
   ============================================ */

section {
  margin-bottom: 4rem;
}

.section-title {
  font-size: 2rem;
  margin-bottom: 1rem;
  text-align: center;
}

.section-description {
  text-align: center;
  color: #666;
  margin-bottom: 2rem;
  max-width: 800px;
  margin-left: auto;
  margin-right: auto;
}

/* ============================================
   SUBJECT GRID & CARDS
   ============================================ */

.subject-section {
  padding: 2rem 0;
}

.subject-title {
  font-size: 2rem;
  text-align: center;
  margin-bottom: 2rem;
}

.subject-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 2rem;
  margin-top: 2rem;
}

.subject-card {
  background: white;
  border: 2px solid #e0e0e0;
  border-radius: 12px;
  padding: 2rem;
  text-align: center;
  transition: all 0.3s ease;
  display: block;
  color: inherit;
  text-decoration: none;
}

.subject-card:hover {
  transform: translateY(-4px);
  box-shadow: 0 8px 24px rgba(0, 0, 0, 0.1);
  border-color: #0056ff;
}

.subject-icon {
  font-size: 3rem;
  color: #0056ff;
  margin-bottom: 1rem;
}

.subject-card .subject-title {
  font-size: 1.5rem;
  margin-bottom: 0.5rem;
  color: #333;
}

.subject-description {
  color: #666;
  font-size: 0.95rem;
}

/* ============================================
   RESOURCES 4-COLUMN LAYOUT (A Level Physics)
   ============================================ */

.resource-disclaimer {
  font-size: 0.85rem;
  color: #666;
  margin-bottom: 1.5rem;
  font-style: italic;
}

.resources-4col {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 1.5rem;
  margin-top: 1rem;
}

.resource-col {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.resource-col .resource-title {
  font-size: 1.1rem;
  margin-bottom: 0.25rem;
}

.resource-pdf-embed {
  min-height: 500px;
  border: 1px solid #e0e0e0;
  border-radius: 8px;
  overflow: hidden;
  background: #f9f9f9;
}

.resource-pdf-embed.resource-pdf-placeholder {
  min-height: 200px;
  display: flex;
  align-items: center;
  justify-content: center;
}

.resource-pdf-embed .pdf-iframe {
  width: 100%;
  height: 550px;
  border: none;
}

.resource-link {
  display: inline-block;
  font-size: 0.95rem;
  color: #0056ff;
  margin-top: 0.25rem;
}

.resource-pdf-link {
  font-size: 0.9rem;
  color: #0056ff;
}

.resource-pdf-link.muted {
  color: #999;
  cursor: default;
}

.resource-video-link {
  margin-top: 0.25rem;
  font-size: 0.9rem;
}

.resource-video-link a {
  color: #0056ff;
}

.coming-soon {
  color: #86868b;
  font-size: 0.95rem;
}

.coming-soon-note {
  color: red;
  font-size: 1rem;
  margin-bottom: 0.75rem;
  line-height: 1.6;
}

@media (max-width: 1024px) {
  .resources-4col {
    grid-template-columns: repeat(2, 1fr);
  }
  .resource-pdf-embed .pdf-iframe {
    height: 450px;
  }
}

@media (max-width: 640px) {
  .resources-4col {
    grid-template-columns: 1fr;
  }
  .resource-pdf-embed .pdf-iframe {
    height: 400px;
  }
}

/* ============================================
   YOUTUBE SECTION
   ============================================ */

.youtube-section {
  padding: 2rem 0;
}

.video-embed {
  margin: 2rem 0;
  border-radius: 8px;
  overflow: hidden;
}

.cta-buttons {
  display: flex;
  gap: 1rem;
  justify-content: center;
  flex-wrap: wrap;
  margin-top: 1.5rem;
}

/* ============================================
   RESOURCE LIST & CENTERED LISTS
   ============================================ */

.resource-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.resource-list li {
  margin-bottom: 0.75rem;
  padding-left: 0;
}

.centered-list {
  text-align: center;
  max-width: 600px;
  margin: 0 auto;
}

.centered-list li {
  text-align: left;
  display: inline-block;
  width: 100%;
}

/* ============================================
   NAVIGATION & HEADER
   ============================================ */

header {
  background-color: #fff;
  border-bottom: 1px solid #e0e0e0;
  padding: 1rem 0;
  position: sticky;
  top: 0;
  z-index: 100;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.05);
}

nav {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 20px;
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-links {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
  gap: 2rem;
  align-items: center;
}

.nav-links li {
  margin: 0;
}

.nav-links a {
  color: #333;
  text-decoration: none;
  font-weight: 500;
  padding: 0.5rem 0;
  transition: color 0.2s ease;
  display: flex;
  align-items: center;
}

.nav-links a:hover {
  color: #0056ff;
}

.nav-links .home-icon {
  font-size: 1.25rem;
  color: #0056ff;
}

.nav-links .home-icon:hover {
  color: #003ad6;
}

.account-icon {
  font-size: 1.25rem;
  color: #0056ff;
  display: flex;
  align-items: center;
}

.account-icon:hover {
  color: #003ad6;
}

.join-btn {
  margin-left: auto;
  padding: 10px 20px;
  font-size: 0.95rem;
}

/* ============================================
   SKIP LINK STYLING
   ============================================ */

.skip-link {
  position: absolute;
  left: -9999px;
  z-index: 999;
  padding: 1em;
  background: #000;
  color: #fff;
  text-decoration: none;
}

.skip-link:focus {
  position: fixed;
  left: 0;
  top: 0;
  z-index: 9999;
  outline: 2px solid #fff;
  outline-offset: -2px;
}

/* Screen reader only class */
.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;
}

/* ============================================
   FOCUS INDICATORS & KEYBOARD NAVIGATION
   ============================================ */

/* Remove default outline and add custom focus styles */
*:focus {
  outline: none;
}

/* Focus-visible: Only show focus indicator when keyboard navigating (modern browsers) */
*:focus-visible {
  outline: 3px solid #0056ff;
  outline-offset: 2px;
  box-shadow: 0 0 0 2px rgba(0, 86, 255, 0.2);
}

/* Fallback for older browsers - show focus on all focus events */
*:focus:not(:focus-visible) {
  outline: 2px solid #0056ff;
  outline-offset: 2px;
}

/* Links - Enhanced focus styles */
a:focus-visible {
  outline: 3px solid #0056ff;
  outline-offset: 2px;
  border-radius: 4px;
  text-decoration: underline;
}

a:focus:not(:focus-visible) {
  outline: 2px solid #0056ff;
  outline-offset: 2px;
  border-radius: 4px;
}

/* Buttons - Enhanced focus styles */
button:focus-visible,
.btn:focus-visible,
input[type="submit"]:focus-visible,
input[type="button"]:focus-visible {
  outline: 3px solid #0056ff;
  outline-offset: 2px;
  box-shadow: 0 0 0 4px rgba(0, 86, 255, 0.2), 0 2px 8px rgba(0, 0, 0, 0.15);
  position: relative;
  z-index: 1;
}

button:focus:not(:focus-visible),
.btn:focus:not(:focus-visible),
input[type="submit"]:focus:not(:focus-visible),
input[type="button"]:focus:not(:focus-visible) {
  outline: 2px solid #0056ff;
  outline-offset: 2px;
  box-shadow: 0 0 0 2px rgba(0, 86, 255, 0.2);
}

/* Form inputs - Enhanced focus styles */
input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: 3px solid #0056ff;
  outline-offset: 2px;
  border-color: #0056ff;
  box-shadow: 0 0 0 4px rgba(0, 86, 255, 0.15), 0 0 0 1px #0056ff;
}

input:focus:not(:focus-visible),
textarea:focus:not(:focus-visible),
select:focus:not(:focus-visible) {
  outline: 2px solid #0056ff;
  outline-offset: 1px;
  border-color: #0056ff;
  box-shadow: 0 0 0 2px rgba(0, 86, 255, 0.15);
}

/* Navigation links - Enhanced focus styles */
nav a:focus-visible,
.nav-links a:focus-visible {
  outline: 3px solid #0056ff;
  outline-offset: 2px;
  background-color: rgba(0, 86, 255, 0.1);
  border-radius: 4px;
  text-decoration: none;
}

nav a:focus:not(:focus-visible),
.nav-links a:focus:not(:focus-visible) {
  outline: 2px solid #0056ff;
  outline-offset: 2px;
  background-color: rgba(0, 86, 255, 0.1);
  border-radius: 4px;
}

/* Calendar slot buttons - Enhanced focus styles */
.slot:focus-visible {
  outline: 3px solid #fff;
  outline-offset: 2px;
  box-shadow: 0 0 0 4px rgba(0, 71, 255, 0.5), 0 2px 8px rgba(0, 0, 0, 0.2);
  transform: translateY(-1px);
  z-index: 1;
  position: relative;
}

.slot:focus:not(:focus-visible) {
  outline: 2px solid #fff;
  outline-offset: 2px;
  box-shadow: 0 0 0 2px rgba(0, 71, 255, 0.5);
}

/* Dropdown options - Enhanced focus styles */
.dropdown .option:focus-visible {
  outline: 3px solid #fff;
  outline-offset: -2px;
  background-color: #003ad6;
  box-shadow: 0 0 0 2px rgba(255, 255, 255, 0.3);
}

.dropdown .option:focus:not(:focus-visible) {
  outline: 2px solid #fff;
  outline-offset: -2px;
  background-color: #003ad6;
}

/* Subject cards and interactive cards - Enhanced focus styles */
.subject-card:focus-visible,
.pricing-card:focus-visible {
  outline: 3px solid #0056ff;
  outline-offset: 4px;
  box-shadow: 0 0 0 4px rgba(0, 86, 255, 0.2), 0 4px 12px rgba(0, 0, 0, 0.15);
  transform: translateY(-2px);
}

.subject-card:focus:not(:focus-visible),
.pricing-card:focus:not(:focus-visible) {
  outline: 2px solid #0056ff;
  outline-offset: 2px;
  box-shadow: 0 0 0 2px rgba(0, 86, 255, 0.2);
}

/* Disabled elements - No focus indicator */
button:disabled:focus,
input:disabled:focus,
.btn:disabled:focus,
.slot.unavailable:focus {
  outline: none;
  box-shadow: none;
  cursor: not-allowed;
}

/* Ensure focus is visible on high contrast backgrounds */
.btn-primary:focus-visible {
  outline-color: #fff;
  outline-offset: 3px;
}

.btn-secondary:focus-visible {
  outline-color: #0056ff;
}

/* Table cells - Focus for keyboard navigation */
td:focus-visible,
th:focus-visible {
  outline: 2px solid #0056ff;
  outline-offset: -2px;
  background-color: rgba(0, 86, 255, 0.1);
}

/* Ensure focus indicators work in dark mode (if applicable) */
@media (prefers-color-scheme: dark) {
  *:focus-visible {
    outline-color: #4a9eff;
  }
  
  button:focus-visible,
  .btn:focus-visible {
    box-shadow: 0 0 0 4px rgba(74, 158, 255, 0.3), 0 2px 8px rgba(0, 0, 0, 0.3);
  }
}

/* Reduce motion for users who prefer it */
@media (prefers-reduced-motion: reduce) {
  *:focus-visible,
  *:focus:not(:focus-visible) {
    transition: none;
  }
  
  .slot:focus-visible,
  .subject-card:focus-visible,
  .pricing-card:focus-visible {
    transform: none;
  }
}

/* ============================================
   INLINE STYLES MOVED TO EXTERNAL CSS
   ============================================ */

/* YouTube icon styling */
.youtube-icon {
  color: #ff0000;
  margin-right: 10px;
}

/* Video loading spinner */
.video-loading {
  text-align: center;
  padding: 20px;
}

.video-loading .fa-spinner {
  font-size: 2rem;
  color: var(--text-secondary, #86868b);
}

.video-loading p {
  margin-top: 12px;
  color: var(--text-secondary, #86868b);
}

/* CTA buttons spacing */
.cta-buttons {
  margin-top: 16px;
}

/* Hero section with green background (tutoring page) */
.hero-section.green-bg {
  background: #28a745;
  color: white;
}

.hero-section.green-bg .hero-title {
  -webkit-text-fill-color: white;
  background: none;
}

.hero-section.green-bg .hero-subtitle {
  color: #fff;
}

.hero-section.green-bg .btn-primary {
  background: white;
  color: #28a745;
  border: 2px solid white;
}

/* Success icon (green checkmark) */
.success-icon {
  color: #28a745;
}

/* Error message container */
.error-message-container {
  display: none;
  margin-bottom: var(--spacing-md, 16px);
  padding: 12px;
  border-radius: var(--border-radius, 8px);
}

.error-message-container.show {
  display: block;
}

.error-message-container.alert-error {
  background: #f8d7da;
  border: 1px solid #f5c6cb;
  color: #721c24;
}

.error-message-container.alert-success {
  background: #d4edda;
  border: 1px solid #c3e6cb;
  color: #155724;
}

/* Admin page styles */
.admin-actions {
  margin-top: 10px;
  display: flex;
  gap: 10px;
}

.admin-status {
  margin-top: 10px;
  color: var(--text-secondary, #86868b);
}

.section-title-spacing {
  margin-top: 20px;
}

/* My bookings input styles */
.bookings-email-input {
  flex: 1;
  padding: 12px;
  border: 1px solid #ccc;
  border-radius: var(--border-radius, 8px);
}

.email-error-display {
  display: block;
  margin-top: 4px;
}

/* Step label spacing */
.step-label-spacing {
  margin-top: var(--spacing-md, 16px);
}

/* Empty state variations */
.empty-state.no-padding {
  padding: 0;
}

.empty-state-icon.large {
  font-size: 2.5rem;
}

.empty-state-message.small {
  font-size: 0.95rem;
}

.empty-state.hidden {
  display: none;
}

.empty-state.margin-top {
  margin-top: 2rem;
}

/* Table cell centering */
.table-cell-center {
  text-align: center;
  padding: 40px 20px;
}

/* Iframe styles */
.video-embed iframe {
  border: none;
  aspect-ratio: 16 / 9;
  width: 100%;
  height: 315px;
}

.video-embed-link {
  display: block;
  position: relative;
  border-radius: 8px;
  overflow: hidden;
  text-decoration: none;
  color: inherit;
  max-width: 100%;
}

.video-embed-link img {
  display: block;
  width: 100%;
  height: auto;
  aspect-ratio: 16 / 9;
  object-fit: cover;
}

.video-embed-play-label {
  display: block;
  text-align: center;
  padding: 12px;
  background: rgba(0, 0, 0, 0.05);
  font-weight: 600;
  color: #0056ff;
  font-size: 0.95rem;
}

.video-embed-link:hover .video-embed-play-label {
  background: rgba(0, 86, 255, 0.08);
}

/* Loading state */
.loading-state {
  text-align: center;
  padding: 20px;
  color: var(--text-secondary, #86868b);
}

.loading-state .fa-spinner {
  margin-right: 8px;
}

/* Status message colors */
.status-success {
  color: #28a745;
}

.status-error {
  color: #c33;
}

/* Error message styling */
.error-message-inline {
  color: #c33;
  padding: 12px;
  background: #f8d7da;
}

/* Warning message styling */
.alert-warning {
  background: #fff3cd;
  border: 1px solid #ffc107;
  color: #856404;
}

/* ============================================
   CONTACT FORM STYLING
   ============================================ */

.contact-form-section {
  background: #fff;
  padding: 3rem 0;
  margin-top: 2rem;
}

.contact-form {
  background: #fff;
  max-width: 800px;
  margin: 0 auto;
  padding: 0;
}

.form-group {
  margin-bottom: 1.5rem;
  display: flex;
  flex-direction: column;
}

.form-group label {
  font-size: 0.95rem;
  font-weight: 500;
  color: #333;
  margin-bottom: 0.5rem;
  display: block;
}

.contact-form input[type="text"],
.contact-form input[type="email"],
.contact-form textarea,
.contact-form select {
  width: 100%;
  padding: 14px 16px;
  font-size: 1rem;
  border: 1px solid #d1d5db;
  border-radius: 8px;
  background-color: #fff;
  color: #333;
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
  font-family: inherit;
}

.contact-form input[type="text"]:focus,
.contact-form input[type="email"]:focus,
.contact-form textarea:focus,
.contact-form select:focus {
  outline: none;
  border-color: #0056ff;
  box-shadow: 0 0 0 3px rgba(0, 86, 255, 0.1);
}

.contact-form input[type="text"]:hover,
.contact-form input[type="email"]:hover,
.contact-form textarea:hover,
.contact-form select:hover {
  border-color: #9ca3af;
}

.contact-form textarea {
  resize: vertical;
  min-height: 120px;
  line-height: 1.5;
}

.contact-form input[type="text"].invalid,
.contact-form input[type="email"].invalid,
.contact-form textarea.invalid {
  border-color: #dc2626;
}

.contact-form input[type="text"].invalid:focus,
.contact-form input[type="email"].invalid:focus,
.contact-form textarea.invalid:focus {
  border-color: #dc2626;
  box-shadow: 0 0 0 3px rgba(220, 38, 38, 0.1);
}

.field-error {
  display: block;
  margin-top: 0.5rem;
  font-size: 0.875rem;
  color: #dc2626;
  min-height: 1.25rem;
}

.field-error.email-error-display {
  display: block;
}

/* Two-column layout for name fields */
.contact-form .form-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1.5rem;
}

@media (max-width: 640px) {
  .contact-form .form-row {
    grid-template-columns: 1fr;
    gap: 0;
  }
}

/* Submit button styling */
.contact-form .btn-primary {
  width: 100%;
  max-width: 200px;
  margin-top: 0.5rem;
  padding: 14px 24px;
  font-size: 1rem;
}