/* ============================================
   IELTS Essay Correction Website - Shared Styles
   ============================================ */

/* ----------------------------------------
   CSS Custom Properties (Design Tokens)
   ---------------------------------------- */
:root {
  /* Primary Colors */
  --color-primary: #4f46e5;
  --color-primary-light: #6366f1;
  --color-primary-dark: #4338ca;
  --color-primary-50: #eef2ff;
  --color-primary-100: #e0e7ff;
  --color-primary-200: #c7d2fe;
  --color-primary-500: #6366f1;
  --color-primary-600: #4f46e5;
  --color-primary-700: #4338ca;

  /* Secondary Colors */
  --color-secondary: #0ea5e9;
  --color-secondary-light: #38bdf8;
  --color-secondary-dark: #0284c7;
  --color-secondary-50: #f0f9ff;
  --color-secondary-100: #e0f2fe;
  --color-secondary-500: #0ea5e9;

  /* Accent Colors */
  --color-accent: #f59e0b;
  --color-accent-light: #fbbf24;
  --color-accent-dark: #d97706;

  /* Success Colors */
  --color-success: #10b981;
  --color-success-light: #34d399;
  --color-success-dark: #059669;
  --color-success-50: #ecfdf5;

  /* Warning Colors */
  --color-warning: #f59e0b;
  --color-warning-light: #fbbf24;
  --color-warning-dark: #d97706;
  --color-warning-50: #fffbeb;

  /* Error Colors */
  --color-error: #ef4444;
  --color-error-light: #f87171;
  --color-error-dark: #dc2626;
  --color-error-50: #fef2f2;

  /* Neutral Colors */
  --color-white: #ffffff;
  --color-gray-50: #f8fafc;
  --color-gray-100: #f1f5f9;
  --color-gray-200: #e2e8f0;
  --color-gray-300: #cbd5e1;
  --color-gray-400: #94a3b8;
  --color-gray-500: #64748b;
  --color-gray-600: #475569;
  --color-gray-700: #334155;
  --color-gray-800: #1e293b;
  --color-gray-900: #0f172a;
  --color-black: #000000;

  /* Dark Theme Colors */
  --color-dark-bg: #0f172a;
  --color-dark-surface: #1e293b;
  --color-dark-border: #334155;

  /* Typography */
  --font-family-primary: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-size-xs: 0.75rem;
  --font-size-sm: 0.875rem;
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 1.875rem;
  --font-size-4xl: 2.25rem;
  --font-size-5xl: 3rem;

  /* Font Weights */
  --font-weight-light: 300;
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --font-weight-extrabold: 800;

  /* Line Heights */
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.625;
  --line-height-loose: 2;

  /* Spacing */
  --spacing-0: 0;
  --spacing-1: 0.25rem;
  --spacing-2: 0.5rem;
  --spacing-3: 0.75rem;
  --spacing-4: 1rem;
  --spacing-5: 1.25rem;
  --spacing-6: 1.5rem;
  --spacing-8: 2rem;
  --spacing-10: 2.5rem;
  --spacing-12: 3rem;
  --spacing-16: 4rem;
  --spacing-20: 5rem;
  --spacing-24: 6rem;

  /* Border Radius */
  --radius-sm: 0.25rem;
  --radius-md: 0.375rem;
  --radius-lg: 0.5rem;
  --radius-xl: 0.75rem;
  --radius-2xl: 1rem;
  --radius-3xl: 1.5rem;
  --radius-full: 9999px;

  /* 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), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-lg: 0 10px 15px -3px rgba(0, 0, 0, 0.1), 0 4px 6px -4px rgba(0, 0, 0, 0.1);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
  --shadow-inner: inset 0 2px 4px 0 rgba(0, 0, 0, 0.05);

  /* Transitions */
  --transition-fast: 150ms ease-in-out;
  --transition-normal: 250ms ease-in-out;
  --transition-slow: 350ms ease-in-out;
  --transition-bounce: 500ms cubic-bezier(0.68, -0.55, 0.265, 1.55);

  /* Z-Index Scale */
  --z-dropdown: 100;
  --z-sticky: 200;
  --z-fixed: 300;
  --z-modal-backdrop: 400;
  --z-modal: 500;
  --z-popover: 600;
  --z-tooltip: 700;
}

/* ----------------------------------------
   Base Styles
   ---------------------------------------- */
html {
  scroll-behavior: smooth;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  line-height: var(--line-height-normal);
  color: var(--color-gray-800);
  background-color: var(--color-white);
}

/* ----------------------------------------
   Animation Keyframes
   ---------------------------------------- */

/* Fade In */
@keyframes fadeIn {
  from {
    opacity: 0;
  }
  to {
    opacity: 1;
  }
}

/* Fade In Up */
@keyframes fadeInUp {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Fade In Down */
@keyframes fadeInDown {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Fade In Left */
@keyframes fadeInLeft {
  from {
    opacity: 0;
    transform: translateX(-20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* Fade In Right */
@keyframes fadeInRight {
  from {
    opacity: 0;
    transform: translateX(20px);
  }
  to {
    opacity: 1;
    transform: translateX(0);
  }
}

/* Scale In */
@keyframes scaleIn {
  from {
    opacity: 0;
    transform: scale(0.9);
  }
  to {
    opacity: 1;
    transform: scale(1);
  }
}

/* Scale In Bounce */
@keyframes scaleInBounce {
  0% {
    opacity: 0;
    transform: scale(0.3);
  }
  50% {
    transform: scale(1.05);
  }
  70% {
    transform: scale(0.9);
  }
  100% {
    opacity: 1;
    transform: scale(1);
  }
}

/* Gauge Fill Animation */
@keyframes gaugeFill {
  from {
    stroke-dashoffset: 283;
  }
  to {
    stroke-dashoffset: var(--gauge-target, 0);
  }
}

/* Pulse */
@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

/* Pulse Ring */
@keyframes pulseRing {
  0% {
    transform: scale(0.8);
    opacity: 1;
  }
  100% {
    transform: scale(1.5);
    opacity: 0;
  }
}

/* Bounce */
@keyframes bounce {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-10px);
  }
}

/* Spin */
@keyframes spin {
  from {
    transform: rotate(0deg);
  }
  to {
    transform: rotate(360deg);
  }
}

/* Shimmer */
@keyframes shimmer {
  0% {
    background-position: -200% 0;
  }
  100% {
    background-position: 200% 0;
  }
}

/* Slide Up */
@keyframes slideUp {
  from {
    transform: translateY(100%);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

/* Slide Down */
@keyframes slideDown {
  from {
    transform: translateY(-100%);
    opacity: 0;
  }
  to {
    transform: translateY(0);
    opacity: 1;
  }
}

/* Progress Bar Fill */
@keyframes progressFill {
  from {
    width: 0%;
  }
  to {
    width: var(--progress-target, 100%);
  }
}

/* Count Up */
@keyframes countUp {
  from {
    --num: 0;
  }
}

/* ----------------------------------------
   Animation Utility Classes
   ---------------------------------------- */
.animate-fadeIn {
  animation: fadeIn var(--transition-normal) forwards;
}

.animate-fadeInUp {
  animation: fadeInUp var(--transition-normal) forwards;
}

.animate-fadeInDown {
  animation: fadeInDown var(--transition-normal) forwards;
}

.animate-fadeInLeft {
  animation: fadeInLeft var(--transition-normal) forwards;
}

.animate-fadeInRight {
  animation: fadeInRight var(--transition-normal) forwards;
}

.animate-scaleIn {
  animation: scaleIn var(--transition-normal) forwards;
}

.animate-scaleInBounce {
  animation: scaleInBounce var(--transition-bounce) forwards;
}

.animate-pulse {
  animation: pulse 2s cubic-bezier(0.4, 0, 0.6, 1) infinite;
}

.animate-bounce {
  animation: bounce 1s infinite;
}

.animate-spin {
  animation: spin 1s linear infinite;
}

.animate-shimmer {
  background: linear-gradient(
    90deg,
    var(--color-gray-200) 25%,
    var(--color-gray-100) 50%,
    var(--color-gray-200) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
}

/* Animation Delays */
.animate-delay-100 { animation-delay: 100ms; }
.animate-delay-200 { animation-delay: 200ms; }
.animate-delay-300 { animation-delay: 300ms; }
.animate-delay-400 { animation-delay: 400ms; }
.animate-delay-500 { animation-delay: 500ms; }
.animate-delay-600 { animation-delay: 600ms; }
.animate-delay-700 { animation-delay: 700ms; }
.animate-delay-800 { animation-delay: 800ms; }

/* Animation Durations */
.animate-fast { animation-duration: var(--transition-fast); }
.animate-normal { animation-duration: var(--transition-normal); }
.animate-slow { animation-duration: var(--transition-slow); }

/* ----------------------------------------
   Scroll Animation Classes
   ---------------------------------------- */
.scroll-animate {
  opacity: 0;
  transform: translateY(20px);
  transition: opacity var(--transition-normal), transform var(--transition-normal);
}

.scroll-animate.is-visible {
  opacity: 1;
  transform: translateY(0);
}

.scroll-animate-left {
  opacity: 0;
  transform: translateX(-30px);
  transition: opacity var(--transition-normal), transform var(--transition-normal);
}

.scroll-animate-left.is-visible {
  opacity: 1;
  transform: translateX(0);
}

.scroll-animate-right {
  opacity: 0;
  transform: translateX(30px);
  transition: opacity var(--transition-normal), transform var(--transition-normal);
}

.scroll-animate-right.is-visible {
  opacity: 1;
  transform: translateX(0);
}

.scroll-animate-scale {
  opacity: 0;
  transform: scale(0.95);
  transition: opacity var(--transition-normal), transform var(--transition-normal);
}

.scroll-animate-scale.is-visible {
  opacity: 1;
  transform: scale(1);
}

/* ----------------------------------------
   Stagger Animation
   ---------------------------------------- */
.stagger-children > * {
  opacity: 0;
  transform: translateY(20px);
}

.stagger-children.is-visible > * {
  animation: fadeInUp var(--transition-normal) forwards;
}

.stagger-children.is-visible > *:nth-child(1) { animation-delay: 0ms; }
.stagger-children.is-visible > *:nth-child(2) { animation-delay: 100ms; }
.stagger-children.is-visible > *:nth-child(3) { animation-delay: 200ms; }
.stagger-children.is-visible > *:nth-child(4) { animation-delay: 300ms; }
.stagger-children.is-visible > *:nth-child(5) { animation-delay: 400ms; }
.stagger-children.is-visible > *:nth-child(6) { animation-delay: 500ms; }

/* ----------------------------------------
   Component Styles
   ---------------------------------------- */

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--spacing-2);
  padding: var(--spacing-3) var(--spacing-6);
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-medium);
  line-height: var(--line-height-tight);
  border-radius: var(--radius-lg);
  border: none;
  cursor: pointer;
  transition: all var(--transition-fast);
  text-decoration: none;
}

.btn:focus {
  outline: 2px solid var(--color-primary-200);
  outline-offset: 2px;
}

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

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

.btn-primary:hover:not(:disabled) {
  background-color: var(--color-primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

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

.btn-secondary:hover:not(:disabled) {
  background-color: var(--color-secondary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-lg);
}

.btn-outline {
  background-color: transparent;
  color: var(--color-primary);
  border: 2px solid var(--color-primary);
}

.btn-outline:hover:not(:disabled) {
  background-color: var(--color-primary-50);
  transform: translateY(-1px);
}

.btn-ghost {
  background-color: transparent;
  color: var(--color-gray-600);
}

.btn-ghost:hover:not(:disabled) {
  background-color: var(--color-gray-100);
  color: var(--color-gray-800);
}

.btn-sm {
  padding: var(--spacing-2) var(--spacing-4);
  font-size: var(--font-size-sm);
}

.btn-lg {
  padding: var(--spacing-4) var(--spacing-8);
  font-size: var(--font-size-lg);
}

/* Cards */
.card {
  background-color: var(--color-white);
  border-radius: var(--radius-xl);
  box-shadow: var(--shadow-md);
  overflow: hidden;
  transition: box-shadow var(--transition-fast), transform var(--transition-fast);
}

.card:hover {
  box-shadow: var(--shadow-xl);
  transform: translateY(-2px);
}

.card-body {
  padding: var(--spacing-6);
}

/* Forms */
.form-group {
  margin-bottom: var(--spacing-4);
}

.form-label {
  display: block;
  margin-bottom: var(--spacing-2);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-gray-700);
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--spacing-3) var(--spacing-4);
  font-family: var(--font-family-primary);
  font-size: var(--font-size-base);
  color: var(--color-gray-800);
  background-color: var(--color-white);
  border: 1px solid var(--color-gray-300);
  border-radius: var(--radius-lg);
  transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-100);
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--color-gray-400);
}

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

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: var(--spacing-1) var(--spacing-3);
  font-size: var(--font-size-xs);
  font-weight: var(--font-weight-semibold);
  border-radius: var(--radius-full);
}

.badge-primary {
  background-color: var(--color-primary-100);
  color: var(--color-primary-700);
}

.badge-success {
  background-color: var(--color-success-50);
  color: var(--color-success-dark);
}

.badge-warning {
  background-color: var(--color-warning-50);
  color: var(--color-warning-dark);
}

.badge-error {
  background-color: var(--color-error-50);
  color: var(--color-error-dark);
}

/* Progress Bar */
.progress-bar {
  width: 100%;
  height: 8px;
  background-color: var(--color-gray-200);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-bar-fill {
  height: 100%;
  background: linear-gradient(90deg, var(--color-primary), var(--color-primary-light));
  border-radius: var(--radius-full);
  transition: width var(--transition-slow);
}

.progress-bar-fill.animate {
  animation: progressFill 1s ease-out forwards;
}

/* Score Circle */
.score-circle {
  position: relative;
  width: 120px;
  height: 120px;
}

.score-circle svg {
  transform: rotate(-90deg);
}

.score-circle-bg {
  fill: none;
  stroke: var(--color-gray-200);
  stroke-width: 8;
}

.score-circle-fill {
  fill: none;
  stroke: var(--color-primary);
  stroke-width: 8;
  stroke-linecap: round;
  stroke-dasharray: 283;
  stroke-dashoffset: 283;
  transition: stroke-dashoffset var(--transition-slow);
}

.score-circle-fill.animate {
  animation: gaugeFill 1.5s ease-out forwards;
}

.score-circle-text {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  color: var(--color-gray-800);
}

/* Loading States */
.loading-skeleton {
  background: linear-gradient(
    90deg,
    var(--color-gray-200) 25%,
    var(--color-gray-100) 50%,
    var(--color-gray-200) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s infinite;
  border-radius: var(--radius-md);
}

.loading-spinner {
  width: 24px;
  height: 24px;
  border: 3px solid var(--color-gray-200);
  border-top-color: var(--color-primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

/* Alerts */
.alert {
  display: flex;
  align-items: flex-start;
  gap: var(--spacing-3);
  padding: var(--spacing-4);
  border-radius: var(--radius-lg);
}

.alert-info {
  background-color: var(--color-secondary-50);
  color: var(--color-secondary-dark);
}

.alert-success {
  background-color: var(--color-success-50);
  color: var(--color-success-dark);
}

.alert-warning {
  background-color: var(--color-warning-50);
  color: var(--color-warning-dark);
}

.alert-error {
  background-color: var(--color-error-50);
  color: var(--color-error-dark);
}

/* Tooltip */
.tooltip {
  position: relative;
}

.tooltip-content {
  position: absolute;
  bottom: 100%;
  left: 50%;
  transform: translateX(-50%) translateY(-8px);
  padding: var(--spacing-2) var(--spacing-3);
  font-size: var(--font-size-sm);
  color: var(--color-white);
  background-color: var(--color-gray-800);
  border-radius: var(--radius-md);
  white-space: nowrap;
  opacity: 0;
  visibility: hidden;
  transition: opacity var(--transition-fast), visibility var(--transition-fast);
  z-index: var(--z-tooltip);
}

.tooltip-content::after {
  content: '';
  position: absolute;
  top: 100%;
  left: 50%;
  transform: translateX(-50%);
  border: 6px solid transparent;
  border-top-color: var(--color-gray-800);
}

.tooltip:hover .tooltip-content {
  opacity: 1;
  visibility: visible;
}

/* ----------------------------------------
   Utility Classes
   ---------------------------------------- */

/* Text Colors */
.text-primary { color: var(--color-primary); }
.text-secondary { color: var(--color-secondary); }
.text-success { color: var(--color-success); }
.text-warning { color: var(--color-warning); }
.text-error { color: var(--color-error); }
.text-gray-400 { color: var(--color-gray-400); }
.text-gray-500 { color: var(--color-gray-500); }
.text-gray-600 { color: var(--color-gray-600); }
.text-gray-700 { color: var(--color-gray-700); }
.text-gray-800 { color: var(--color-gray-800); }

/* Background Colors */
.bg-primary { background-color: var(--color-primary); }
.bg-primary-50 { background-color: var(--color-primary-50); }
.bg-secondary { background-color: var(--color-secondary); }
.bg-gray-50 { background-color: var(--color-gray-50); }
.bg-gray-100 { background-color: var(--color-gray-100); }
.bg-dark { background-color: var(--color-dark-bg); }

/* Gradient Backgrounds */
.bg-gradient-primary {
  background: linear-gradient(135deg, var(--color-primary) 0%, var(--color-primary-light) 100%);
}

.bg-gradient-hero {
  background: linear-gradient(135deg, var(--color-primary-50) 0%, var(--color-secondary-50) 100%);
}

/* Focus Styles */
.focus-ring:focus {
  outline: none;
  box-shadow: 0 0 0 3px var(--color-primary-200);
}

/* 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: 0;
}

/* Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
  
  html {
    scroll-behavior: auto;
  }
}