:root {
  /* =============================
     Color System
     ============================= */
  --color-background: #f4f6f5;
  --color-surface: #ffffff;
  --color-text: #1f2933;
  --color-text-muted: #6b7280;

  --color-primary: #4c9383; /* soft natural green */
  --color-primary-soft: #e0f1ec;
  --color-primary-strong: #2f6a5c;

  --color-success: #3b9b6a;
  --color-warning: #d59b37;
  --color-danger: #d46363;

  --color-gray-50: #f9fafb;
  --color-gray-100: #f3f4f6;
  --color-gray-200: #e5e7eb;
  --color-gray-300: #d1d5db;
  --color-gray-400: #9ca3af;
  --color-gray-500: #6b7280;
  --color-gray-600: #4b5563;
  --color-gray-700: #374151;
  --color-gray-800: #1f2933;
  --color-gray-900: #111827;

  /* Subtle accent inspired by calming blues */
  --color-accent: #5a8fb8;
  --color-accent-soft: #e3edf6;

  /* =============================
     Typography
     ============================= */
  --font-sans: system-ui, -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", Roboto, "Noto Sans", sans-serif;
  --font-serif: "Georgia", "Times New Roman", serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, "Liberation Mono", "Courier New", monospace;

  --font-size-xs: 0.75rem;   /* 12px */
  --font-size-sm: 0.875rem;  /* 14px */
  --font-size-base: 1rem;    /* 16px */
  --font-size-md: 1.0625rem; /* 17px */
  --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-height-tight: 1.2;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.7;

  /* =============================
     Spacing Scale (px values)
     ============================= */
  --space-0: 0;
  --space-1: 2px;
  --space-2: 4px;
  --space-3: 6px;
  --space-4: 8px;
  --space-5: 10px;
  --space-6: 12px;
  --space-8: 16px;
  --space-10: 20px;
  --space-12: 24px;
  --space-16: 32px;
  --space-20: 40px;
  --space-24: 48px;
  --space-28: 56px;
  --space-32: 64px;
  --space-40: 80px;
  --space-48: 96px;

  /* =============================
     Radius & Shadows
     ============================= */
  --radius-none: 0;
  --radius-sm: 4px;
  --radius-md: 8px;
  --radius-lg: 16px;
  --radius-pill: 999px;

  --shadow-xs: 0 1px 2px rgba(15, 23, 42, 0.04);
  --shadow-sm: 0 4px 12px rgba(15, 23, 42, 0.06);
  --shadow-md: 0 10px 30px rgba(15, 23, 42, 0.08);

  /* =============================
     Transitions / Motion
     ============================= */
  --transition-fast: 120ms ease-out;
  --transition-normal: 200ms ease-out;
  --transition-slow: 320ms ease-out;
}

/* =============================
   Reset / Normalize
   ============================= */

*,
*::before,
*::after {
  box-sizing: border-box;
}

html,
body,
div,
span,
applet,
object,
iframe,
h1,
h2,
h3,
h4,
h5,
h6,
p,
blockquote,
pre,
a,
abbr,
acronym,
address,
big,
cite,
code,
del,
dfn,
em,
img,
ins,
kbd,
q,
s,
samp,
small,
strike,
strong,
sub,
sup,
tt,
var,
b,
u,
i,
center,
dl,
dt,
dd,
ol,
ul,
li,
fieldset,
form,
label,
legend,
table,
caption,
tbody,
tfoot,
thead,
tr,
th,
td,
article,
aside,
canvas,
details,
embed,
figure,
figcaption,
footer,
header,
main,
menu,
nav,
output,
ruby,
section,
summary,
time,
mark,
audio,
video {
  margin: 0;
  padding: 0;
  border: 0;
  font: inherit;
  vertical-align: baseline;
}

html {
  line-height: 1.15;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  min-height: 100vh;
}

article,
aside,
footer,
header,
nav,
section,
main {
  display: block;
}

ol,
ul {
  list-style: none;
}

img,
svg,
video,
canvas,
audio,
iframe,
embed,
object {
  display: block;
  max-width: 100%;
}

img,
video {
  height: auto;
}

button,
input,
select,
textarea {
  margin: 0;
  font: inherit;
  color: inherit;
}

button {
  border-radius: 0;
}

button,
[role="button"],
input[type="button"],
input[type="submit"],
input[type="reset"] {
  cursor: pointer;
}

button[disabled],
input[disabled],
select[disabled],
textarea[disabled] {
  cursor: not-allowed;
}

:focus {
  outline: none;
}

/* =============================
   Base Styles
   ============================= */

body {
  font-family: var(--font-sans);
  font-size: var(--font-size-base);
  line-height: var(--line-height-relaxed);
  background-color: var(--color-background);
  color: var(--color-text);
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
}

main {
  min-height: 60vh;
}

h1,
h2,
h3,
h4,
h5,
h6 {
  font-weight: 500;
  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-16);
}

h2 {
  font-size: var(--font-size-3xl);
  letter-spacing: -0.015em;
  margin-bottom: var(--space-12);
}

h3 {
  font-size: var(--font-size-2xl);
  margin-bottom: var(--space-10);
}

h4 {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-8);
}

h5 {
  font-size: var(--font-size-lg);
  margin-bottom: var(--space-6);
}

h6 {
  font-size: var(--font-size-base);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--color-text-muted);
  margin-bottom: var(--space-4);
}

p {
  margin-bottom: var(--space-8);
  color: var(--color-text);
}

p:last-child {
  margin-bottom: 0;
}

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

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

a:focus-visible {
  outline: 2px solid var(--color-accent);
  outline-offset: 3px;
}

strong,
b {
  font-weight: 600;
}

hr {
  border: none;
  border-top: 1px solid var(--color-gray-200);
  margin: var(--space-16) 0;
}

code,
pre {
  font-family: var(--font-mono);
}

/* =============================
   Accessibility & Motion
   ============================= */

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

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

/* =============================
   Utility Classes
   ============================= */

/* Layout */

.container {
  width: 100%;
  max-width: 1120px;
  margin-left: auto;
  margin-right: auto;
  padding-left: var(--space-16);
  padding-right: var(--space-16);
}

@media (min-width: 1200px) {
  .container {
    max-width: 1200px;
  }
}

.section {
  padding-top: var(--space-32);
  padding-bottom: var(--space-32);
}

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

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

/* Flex */

.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-sm {
  gap: var(--space-8);
}

.gap-md {
  gap: var(--space-16);
}

.gap-lg {
  gap: var(--space-24);
}

/* Grid */

.grid {
  display: grid;
  gap: var(--space-16);
}

.grid-2 {
  display: grid;
  gap: var(--space-16);
}

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

.grid-3 {
  display: grid;
  gap: var(--space-20);
}

@media (min-width: 992px) {
  .grid-3 {
    grid-template-columns: repeat(3, minmax(0, 1fr));
  }
}

/* Spacing helpers (minimal set) */

.mt-0 { margin-top: 0 !important; }
.mb-0 { margin-bottom: 0 !important; }
.mt-sm { margin-top: var(--space-8) !important; }
.mb-sm { margin-bottom: var(--space-8) !important; }
.mt-md { margin-top: var(--space-16) !important; }
.mb-md { margin-bottom: var(--space-16) !important; }
.mt-lg { margin-top: var(--space-24) !important; }
.mb-lg { margin-bottom: var(--space-24) !important; }

.pt-sm { padding-top: var(--space-8) !important; }
.pb-sm { padding-bottom: var(--space-8) !important; }
.pt-md { padding-top: var(--space-16) !important; }
.pb-md { padding-bottom: var(--space-16) !important; }
.pt-lg { padding-top: var(--space-24) !important; }
.pb-lg { padding-bottom: var(--space-24) !important; }

/* Text alignment */

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

/* 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;
}

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

/* Buttons */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-4);
  padding: 0.6rem 1.5rem;
  border-radius: var(--radius-pill);
  border: 1px solid transparent;
  background-color: var(--color-primary);
  color: #ffffff;
  font-size: var(--font-size-sm);
  font-weight: 500;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  text-decoration: none;
  transition: background-color var(--transition-normal),
              border-color var(--transition-normal),
              color var(--transition-normal),
              box-shadow var(--transition-normal),
              transform var(--transition-fast);
}

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

.btn:active {
  transform: translateY(0);
  box-shadow: var(--shadow-xs);
}

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

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

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

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

.btn--secondary:hover {
  background-color: #4a7da0;
}

.btn--block {
  width: 100%;
}

.btn[disabled],
.btn--disabled {
  opacity: 0.55;
  cursor: not-allowed;
  box-shadow: none;
  transform: none;
}

/* Form Elements */

.input,
textarea,
select {
  width: 100%;
  padding: 0.7rem 0.9rem;
  border-radius: var(--radius-md);
  border: 1px solid var(--color-gray-200);
  background-color: #ffffff;
  color: var(--color-text);
  font-size: var(--font-size-sm);
  line-height: var(--line-height-normal);
  transition: border-color var(--transition-normal),
              box-shadow var(--transition-normal),
              background-color var(--transition-normal);
}

.input::placeholder,
textarea::placeholder {
  color: var(--color-text-muted);
}

.input:focus-visible,
textarea:focus-visible,
select:focus-visible {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 1px var(--color-primary-soft), var(--shadow-xs);
}

.input[disabled],
textarea[disabled],
select[disabled] {
  background-color: var(--color-gray-100);
  color: var(--color-text-muted);
}

label {
  display: inline-block;
  margin-bottom: var(--space-4);
  font-size: var(--font-size-sm);
  color: var(--color-text);
}

.form-group {
  margin-bottom: var(--space-12);
}

.form-help {
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
  margin-top: var(--space-2);
}

/* Card */

.card {
  background-color: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: var(--space-20);
  box-shadow: var(--shadow-sm);
}

.card--soft {
  background: linear-gradient(145deg, #ffffff, #f7faf9);
}

.card-header {
  margin-bottom: var(--space-12);
}

.card-title {
  font-size: var(--font-size-xl);
  margin-bottom: var(--space-4);
}

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

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

/* Tags / Pills (useful for class levels, styles, etc.) */

.pill {
  display: inline-flex;
  align-items: center;
  padding: 0.15rem 0.6rem;
  border-radius: var(--radius-pill);
  border: 1px solid var(--color-gray-200);
  background-color: var(--color-gray-50);
  font-size: var(--font-size-xs);
  color: var(--color-text-muted);
}

.pill--success {
  background-color: rgba(59, 155, 106, 0.06);
  border-color: rgba(59, 155, 106, 0.2);
  color: var(--color-success);
}

.pill--primary {
  background-color: var(--color-primary-soft);
  border-color: rgba(76, 147, 131, 0.35);
  color: var(--color-primary-strong);
}

/* Hero text helper for calm, large intros */

.hero-title {
  font-size: clamp(2.2rem, 4vw, 3rem);
  line-height: var(--line-height-tight);
  letter-spacing: -0.03em;
}

.hero-subtitle {
  margin-top: var(--space-8);
  font-size: var(--font-size-lg);
  color: var(--color-text-muted);
  max-width: 36rem;
}

/* Muted panel for schedules or notices */

.panel-muted {
  padding: var(--space-16);
  border-radius: var(--radius-md);
  background-color: var(--color-accent-soft);
  color: var(--color-text);
}

.panel-muted p:last-child {
  margin-bottom: 0;
}

/* =============================
   End of base.css
   ============================= */