/* ========================================================================
   Variables
   ====================================================================== */
:root {
  /* Colors */
  --color-background: #f5f7fb;
  --color-surface: #ffffff;
  --color-text: #1a2234;
  --color-text-muted: #5c6477;
  --color-primary: #1f6fe5;
  --color-primary-soft: #e0ebff;
  --color-primary-strong: #1551a8;
  --color-success: #1abf6b;
  --color-warning: #ffb020;
  --color-danger: #e55353;

  --gray-50: #f8fafc;
  --gray-100: #edf1f7;
  --gray-200: #dde3f0;
  --gray-300: #c6cfdf;
  --gray-400: #9ba4b8;
  --gray-500: #6b7388;
  --gray-600: #4b5368;
  --gray-700: #363d50;
  --gray-800: #252b3a;
  --gray-900: #151824;

  /* Typography */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI',
    Roboto, 'Helvetica Neue', Arial, 'Noto Sans', sans-serif, 'Apple Color Emoji',
    'Segoe UI Emoji', 'Segoe UI Symbol', 'Noto Color Emoji';
  --font-heading: 'Segoe UI', system-ui, -apple-system, BlinkMacSystemFont,
    Roboto, 'Helvetica Neue', Arial, sans-serif;

  /* Font sizes (desktop base: 16px) */
  --font-size-xs: 0.75rem;   /* 12px */
  --font-size-sm: 0.875rem;  /* 14px */
  --font-size-md: 1rem;      /* 16px */
  --font-size-lg: 1.125rem;  /* 18px */
  --font-size-xl: 1.25rem;   /* 20px */
  --font-size-2xl: 1.5rem;   /* 24px */
  --font-size-3xl: 1.875rem; /* 30px */
  --font-size-4xl: 2.25rem;  /* 36px */

  /* Line heights */
  --line-height-tight: 1.2;
  --line-height-snug: 1.35;
  --line-height-normal: 1.6;
  --line-height-relaxed: 1.8;

  /* Spacing scale (0–96px) */
  --space-0: 0;
  --space-1: 0.25rem;  /* 4px */
  --space-2: 0.5rem;   /* 8px */
  --space-3: 0.75rem;  /* 12px */
  --space-4: 1rem;     /* 16px */
  --space-5: 1.25rem;  /* 20px */
  --space-6: 1.5rem;   /* 24px */
  --space-8: 2rem;     /* 32px */
  --space-10: 2.5rem;  /* 40px */
  --space-12: 3rem;    /* 48px */
  --space-16: 4rem;    /* 64px */
  --space-20: 5rem;    /* 80px */
  --space-24: 6rem;    /* 96px */

  /* Radius */
  --radius-sm: 0.25rem;  /* 4px */
  --radius-md: 0.5rem;   /* 8px */
  --radius-lg: 0.75rem;  /* 12px */
  --radius-xl: 1rem;     /* 16px */
  --radius-full: 9999px;

  /* Shadows (soft, educational feel) */
  --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-sm: 0 2px 8px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 8px 24px rgba(15, 23, 42, 0.08);
  --shadow-lg: 0 16px 40px rgba(15, 23, 42, 0.10);

  /* Transitions */
  --transition-fast: 120ms ease-out;
  --transition-normal: 180ms ease-out;
  --transition-slow: 240ms ease-out;

  /* Layout */
  --container-max-width: 1120px;
}

@media (max-width: 768px) {
  :root {
    --font-size-3xl: 1.75rem;
    --font-size-4xl: 2rem;
  }
}

/* ========================================================================
   Reset / Normalize
   ====================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  -webkit-text-size-adjust: 100%;
  text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  margin: 0;
}

h1, h2, h3, h4, h5, h6,
p, figure, blockquote,
dl, dd {
  margin: 0;
}

ul[role='list'],
ol[role='list'] {
  list-style: none;
  margin: 0;
  padding: 0;
}

img,
picture,
video,
canvas,
svg {
  display: block;
  max-width: 100%;
}

img {
  height: auto;
}

button,
input,
select,
textarea {
  font: inherit;
  color: inherit;
}

button {
  border: none;
  padding: 0;
  background: none;
}

fieldset {
  margin: 0;
  padding: 0;
  border: 0;
}

textarea {
  resize: vertical;
}

/* Remove default focus outlines, handled with :focus-visible */
:focus {
  outline: none;
}

/* ========================================================================
   Base Styles
   ====================================================================== */
body {
  min-height: 100vh;
  font-family: var(--font-sans);
  font-size: var(--font-size-md);
  line-height: var(--line-height-normal);
  background-color: var(--color-background);
  color: var(--color-text);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

main {
  display: block;
}

/* Headings: modern, clear hierarchy */
h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-heading);
  font-weight: 700;
  color: var(--color-text);
  line-height: var(--line-height-tight);
}

h1 {
  font-size: var(--font-size-4xl);
  letter-spacing: -0.02em;
  margin-bottom: var(--space-4);
}

h2 {
  font-size: var(--font-size-3xl);
  letter-spacing: -0.015em;
  margin-bottom: var(--space-3);
}

h3 {
  font-size: var(--font-size-2xl);
  letter-spacing: -0.01em;
  margin-bottom: var(--space-3);
}

h4 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-2);
}

h5 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-2);
}

h6 {
  font-size: var(--font-size-md);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-2);
}

p {
  margin-bottom: var(--space-4);
  color: var(--color-text-muted);
  max-width: 72ch;
}

strong {
  font-weight: 600;
}

/* Links: clean, professional */
a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color var(--transition-normal),
    text-decoration-color var(--transition-normal),
    background-color var(--transition-normal);
}

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

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

/* Lists */
ul,
ol {
  padding-left: 1.25rem;
  margin: 0 0 var(--space-4) 0;
}



/* Horizontal rule */
hr {
  border: none;
  border-top: 1px solid var(--gray-200);
  margin: var(--space-6) 0;
}

/* ========================================================================
   Accessibility & Reduced Motion
   ====================================================================== */
:focus-visible {
  outline: 3px solid var(--color-primary);
  outline-offset: 3px;
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    scroll-behavior: auto !important;
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
  }
}

/* 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;
}

/* ========================================================================
   Utilities
   ====================================================================== */

/* Container: centered, responsive, good for course and pricing sections */
.container {
  width: 100%;
  max-width: var(--container-max-width);
  margin-inline: auto;
  padding-inline: var(--space-4);
}

@media (min-width: 1024px) {
  .container {
    padding-inline: var(--space-6);
  }
}

.section {
  padding-block: var(--space-12);
}

.section--light {
  background-color: var(--color-background);
}

.section--surface {
  background-color: var(--color-surface);
}

/* Flex helpers */
.flex {
  display: flex;
}

.inline-flex {
  display: inline-flex;
}

.flex-center {
  display: flex;
  align-items: center;
  justify-content: center;
}

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

.flex-column {
  display: flex;
  flex-direction: column;
}

.flex-wrap {
  flex-wrap: wrap;
}

.gap-2 {
  gap: var(--space-2);
}

.gap-4 {
  gap: var(--space-4);
}

.gap-6 {
  gap: var(--space-6);
}

/* Grid helpers */
.grid {
  display: grid;
  gap: var(--space-4);
}

.grid-2 {
  display: grid;
  gap: var(--space-6);
}

.grid-3 {
  display: grid;
  gap: var(--space-6);
}

@media (min-width: 768px) {
  .grid-2 {
    grid-template-columns: repeat(2, minmax(0, 1fr));
  }

  .grid-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

.text-center {
  text-align: center;
}

.text-right {
  text-align: right;
}

.m-auto {
  margin: auto;
}

.mt-0 { margin-top: 0; }
.mt-4 { margin-top: var(--space-4); }
.mt-6 { margin-top: var(--space-6); }
.mt-8 { margin-top: var(--space-8); }

.mb-0 { margin-bottom: 0; }
.mb-2 { margin-bottom: var(--space-2); }
.mb-4 { margin-bottom: var(--space-4); }
.mb-6 { margin-bottom: var(--space-6); }
.mb-8 { margin-bottom: var(--space-8); }

.py-8 {
  padding-block: var(--space-8);
}

.py-12 {
  padding-block: var(--space-12);
}

.rounded-md {
  border-radius: var(--radius-md);
}

.rounded-lg {
  border-radius: var(--radius-lg);
}

.shadow-sm {
  box-shadow: var(--shadow-sm);
}

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

.bg-surface {
  background-color: var(--color-surface);
}

.bg-primary-soft {
  background-color: var(--color-primary-soft);
}

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

.badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.125rem 0.5rem;
  border-radius: var(--radius-full);
  font-size: var(--font-size-xs);
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  background-color: var(--gray-100);
  color: var(--gray-700);
}

.badge--primary {
  background-color: var(--color-primary-soft);
  color: var(--color-primary-strong);
}

/* ========================================================================
   Components
   ====================================================================== */

/* Buttons - primary CTAs for enrollment and course selection */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-full);
  border: 1px solid transparent;
  font-weight: 600;
  font-size: var(--font-size-sm);
  line-height: 1.2;
  cursor: pointer;
  text-decoration: none;
  white-space: nowrap;
  transition:
    background-color var(--transition-normal),
    color var(--transition-normal),
    border-color var(--transition-normal),
    box-shadow var(--transition-normal),
    transform var(--transition-fast);
}

.btn--primary {
  background-color: var(--color-primary);
  border-color: var(--color-primary);
  color: #ffffff;
  box-shadow: var(--shadow-sm);
}

.btn--primary:hover {
  background-color: var(--color-primary-strong);
  border-color: var(--color-primary-strong);
  box-shadow: var(--shadow-md);
  transform: translateY(-1px);
}

.btn--outline {
  background-color: transparent;
  border-color: var(--gray-300);
}

.btn--outline:hover {
  border-color: var(--color-primary);
  color: var(--color-primary-strong);
  background-color: #ffffff;
}

.btn--ghost {
  background-color: transparent;
  border-color: transparent;
  color: var(--color-primary);
}

.btn--ghost:hover {
  background-color: rgba(31, 111, 229, 0.06);
}

.btn:disabled,
.btn[aria-disabled='true'] {
  opacity: 0.6;
  cursor: not-allowed;
  box-shadow: none;
  transform: none;
}

.btn:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 3px;
}

/* Inputs - for forms, enrollment, contact */
.input,
.select,
.textarea {
  width: 100%;
  padding: 0.625rem 0.75rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--gray-300);
  background-color: #ffffff;
  font-size: var(--font-size-sm);
  color: var(--color-text);
  transition:
    border-color var(--transition-normal),
    box-shadow var(--transition-normal),
    background-color var(--transition-normal);
}

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

.input:focus-visible,
.select:focus-visible,
.textarea:focus-visible {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 1px var(--color-primary-soft), var(--shadow-xs);
}

.input[aria-invalid='true'],
.textarea[aria-invalid='true'],
.select[aria-invalid='true'] {
  border-color: var(--color-danger);
}

.label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--gray-700);
  margin-bottom: 0.25rem;
}

.field-help {
  font-size: var(--font-size-xs);
  color: var(--gray-500);
  margin-top: 0.25rem;
}

.field-error {
  font-size: var(--font-size-xs);
  color: var(--color-danger);
  margin-top: 0.25rem;
}

/* Card - for course levels, teacher profiles, pricing */
.card {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-sm);
  padding: var(--space-5);
  border: 1px solid rgba(148, 163, 184, 0.16);
}

.card--hoverable {
  transition:
    box-shadow var(--transition-normal),
    transform var(--transition-normal),
    border-color var(--transition-normal),
    background-color var(--transition-normal);
}

.card--hoverable:hover {
  box-shadow: var(--shadow-md);
  transform: translateY(-2px);
  border-color: rgba(37, 99, 235, 0.18);
}

.card__header {
  margin-bottom: var(--space-4);
}

.card__title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-1);
}

.card__subtitle {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

.card__body {
  font-size: var(--font-size-sm);
}

.card__footer {
  margin-top: var(--space-4);
}

/* Hero image / media wrapper (for dynamic classroom visuals) */
.media-rounded {
  border-radius: var(--radius-xl);
  overflow: hidden;
}

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

/* Navigation basics (clean, modern top nav) */
.navbar {
  position: sticky;
  top: 0;
  z-index: 20;
  backdrop-filter: blur(14px);
  background: rgba(248, 250, 252, 0.86);
  border-bottom: 1px solid rgba(148, 163, 184, 0.18);
}

.navbar__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 4.25rem;
}

.navbar__brand {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: 700;
  font-size: var(--font-size-lg);
  color: var(--color-text);
}

.navbar__links {
  display: flex;
  align-items: center;
  gap: var(--space-4);
}

.navbar__link {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-muted);
  padding: 0.25rem 0.5rem;
  border-radius: var(--radius-full);
  transition:
    color var(--transition-normal),
    background-color var(--transition-normal);
}

.navbar__link:hover {
  color: var(--color-text);
  background-color: rgba(148, 163, 184, 0.12);
}

.navbar__link--active {
  color: var(--color-primary-strong);
  background-color: var(--color-primary-soft);
}

@media (max-width: 768px) {
  .navbar__links {
    display: none;
  }
}

/* Callout / info banner (for schedules, flexible learning notes) */
.callout {
  border-radius: var(--radius-lg);
  padding: var(--space-4);
  background: linear-gradient(135deg, #e0ebff, #f5f7fb);
  border: 1px solid rgba(59, 130, 246, 0.25);
}

.callout__title {
  font-weight: 600;
  margin-bottom: 0.25rem;
}

.callout__text {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
}

/* Pricing highlight (results-driven & clear pricing) */
.price-tag {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  color: var(--color-primary-strong);
}

.price-tag__unit {
  font-size: var(--font-size-sm);
  font-weight: 500;
  color: var(--color-text-muted);
}

/* Tables (for schedules and levels) */
.table {
  width: 100%;
  border-collapse: collapse;
  font-size: var(--font-size-sm);
}

.table th,
.table td {
  padding: 0.75rem 0.75rem;
  text-align: left;
  border-bottom: 1px solid var(--gray-200);
}

.table thead th {
  font-weight: 600;
  color: var(--gray-700);
  background-color: var(--gray-50);
}

.table tbody tr:nth-child(even) {
  background-color: #fafbff;
}

/* Footer basics */
.footer {
  border-top: 1px solid var(--gray-200);
  background-color: #ffffff;
  padding-block: var(--space-8);
  font-size: var(--font-size-sm);
  color: var(--gray-500);
}