/* ==========================================================================
   DocSphere Learn — Design System
   Premium SaaS aesthetic (Apple / Linear / Stripe / Notion / Framer influence):
   restrained neutral palette + one gradient accent, generous whitespace,
   soft elevation, and understated motion. Mobile-first — base rules target
   small screens, min-width media queries layer on enhancements.
   ========================================================================== */

:root {
  /* Color */
  --color-bg: #ffffff;
  --color-surface: #f7f7f9;
  --color-surface-2: #ffffff;
  --color-text: #0b0b0f;
  --color-text-secondary: #5c5c66;
  --color-border: rgba(11, 11, 15, 0.08);
  --color-border-strong: rgba(11, 11, 15, 0.14);

  --color-accent: #0071e3;
  --color-accent-2: #7c3aed;
  --color-accent-contrast: #ffffff;

  --gradient-brand: linear-gradient(135deg, var(--color-accent), var(--color-accent-2));
  --gradient-text: linear-gradient(135deg, #0071e3, #7c3aed 60%, #ec4899);

  --color-success-bg: #e6f7ed;
  --color-success-text: #0f7a3d;
  --color-warning-bg: #fef3e2;
  --color-warning-text: #9a5b00;
  --color-neutral-bg: #eef0f3;
  --color-neutral-text: #52525b;

  /* Typography */
  --font-family: -apple-system, BlinkMacSystemFont, "SF Pro Display", "SF Pro Text",
    "Segoe UI", Roboto, Helvetica, Arial, sans-serif;

  /* Spacing scale */
  --space-1: 8px;
  --space-2: 16px;
  --space-3: 24px;
  --space-4: 32px;
  --space-5: 48px;
  --space-6: 64px;
  --space-7: 96px;
  --space-8: 128px;

  /* Radius */
  --radius-sm: 10px;
  --radius-md: 18px;
  --radius-lg: 28px;
  --radius-full: 999px;

  /* Elevation */
  --shadow-sm: 0 1px 2px rgba(11, 11, 15, 0.06), 0 1px 1px rgba(11, 11, 15, 0.04);
  --shadow-md: 0 8px 24px rgba(11, 11, 15, 0.08), 0 2px 6px rgba(11, 11, 15, 0.04);
  --shadow-lg: 0 24px 64px rgba(11, 11, 15, 0.12), 0 8px 20px rgba(11, 11, 15, 0.06);

  /* Motion */
  --ease-out-expo: cubic-bezier(0.16, 1, 0.3, 1);
  --transition-fast: 160ms var(--ease-out-expo);
  --transition-base: 280ms var(--ease-out-expo);
  --transition-slow: 600ms var(--ease-out-expo);

  /* Layout */
  --max-content-width: 1120px;
  --header-height: 64px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --color-bg: #0b0b0f;
    --color-surface: #131316;
    --color-surface-2: #17171b;
    --color-text: #f5f5f7;
    --color-text-secondary: #9a9aa5;
    --color-border: rgba(255, 255, 255, 0.1);
    --color-border-strong: rgba(255, 255, 255, 0.16);

    --color-accent: #3b9dff;
    --color-accent-2: #a682ff;

    --color-success-bg: rgba(15, 122, 61, 0.18);
    --color-success-text: #4ade80;
    --color-warning-bg: rgba(154, 91, 0, 0.2);
    --color-warning-text: #fbbf24;
    --color-neutral-bg: rgba(255, 255, 255, 0.06);
    --color-neutral-text: #c4c4cc;
  }
}

/* Reset ------------------------------------------------------------------ */

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

html {
  -webkit-text-size-adjust: 100%;
  scroll-padding-top: var(--header-height);
}

@media (prefers-reduced-motion: no-preference) {
  html {
    scroll-behavior: smooth;
  }
}

body {
  font-family: var(--font-family);
  color: var(--color-text);
  background: var(--color-bg);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  overflow-x: hidden;
}

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

a {
  color: inherit;
  text-decoration: none;
}

ul {
  list-style: none;
}

button {
  font: inherit;
  color: inherit;
  background: none;
  border: none;
  cursor: pointer;
}

h1, h2, h3, h4 {
  font-weight: 600;
  letter-spacing: -0.02em;
  line-height: 1.15;
}

.skip-link {
  position: absolute;
  left: -9999px;
  top: 0;
  background: var(--color-text);
  color: var(--color-bg);
  padding: var(--space-1) var(--space-2);
  border-radius: var(--radius-sm);
  z-index: 100;
}

.skip-link:focus {
  left: var(--space-2);
  top: var(--space-2);
}

/* Layout ------------------------------------------------------------------ */

.container {
  max-width: var(--max-content-width);
  margin: 0 auto;
  padding: 0 var(--space-3);
}

section {
  padding: var(--space-7) 0;
}

.section-head {
  text-align: center;
  max-width: 560px;
  margin: 0 auto var(--space-5);
}

.section-head h2 {
  font-size: clamp(1.75rem, 4vw, 2.5rem);
  margin-top: var(--space-1);
}

.section-lede {
  font-size: 1.0625rem;
  color: var(--color-text-secondary);
  margin-top: var(--space-2);
}

.eyebrow {
  display: inline-block;
  font-size: 0.8125rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--color-accent);
}

.text-gradient {
  background: var(--gradient-text);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

/* Reveal-on-scroll ---------------------------------------------------------- */

[data-reveal] {
  opacity: 0;
  transform: translateY(16px);
}

[data-reveal].in-view {
  opacity: 1;
  transform: none;
  transition: opacity var(--transition-slow), transform var(--transition-slow);
}

@media (prefers-reduced-motion: reduce) {
  [data-reveal] {
    opacity: 1;
    transform: none;
  }
}

/* Buttons ------------------------------------------------------------------ */

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-1);
  padding: 12px 22px;
  font-size: 0.9375rem;
  font-weight: 600;
  border-radius: var(--radius-full);
  transition: transform var(--transition-fast), box-shadow var(--transition-fast), background var(--transition-fast), opacity var(--transition-fast);
  white-space: nowrap;
}

.btn:active {
  transform: scale(0.97);
}

.btn--primary {
  background: var(--gradient-brand);
  color: var(--color-accent-contrast);
  box-shadow: var(--shadow-sm);
}

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

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

.btn--ghost:hover {
  border-color: var(--color-border-strong);
  transform: translateY(-1px);
}

.btn--sm {
  padding: 8px 16px;
  font-size: 0.875rem;
}

.btn--lg {
  padding: 14px 28px;
  font-size: 1rem;
}

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

/* Header ------------------------------------------------------------------ */

.site-header {
  position: sticky;
  top: 0;
  z-index: 50;
  height: var(--header-height);
  display: flex;
  align-items: center;
  background: var(--color-bg);
  background: color-mix(in srgb, var(--color-bg) 80%, transparent);
  backdrop-filter: saturate(180%) blur(20px);
  -webkit-backdrop-filter: saturate(180%) blur(20px);
  border-bottom: 1px solid var(--color-border);
}

.header__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-3);
}

.logo {
  font-size: 1.0625rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  flex-shrink: 0;
}

.logo span {
  color: var(--color-accent);
}

.nav {
  display: none;
  align-items: center;
  gap: var(--space-4);
  font-size: 0.9375rem;
  font-weight: 500;
}

.nav a {
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

.nav a:hover {
  color: var(--color-text);
}

.header__actions {
  display: flex;
  align-items: center;
  gap: var(--space-2);
}

.header__actions .btn--primary {
  display: none;
}

.nav-toggle {
  display: flex;
  flex-direction: column;
  justify-content: center;
  gap: 4px;
  width: 32px;
  height: 32px;
  padding: 4px;
}

.nav-toggle span {
  display: block;
  height: 2px;
  width: 100%;
  background: var(--color-text);
  border-radius: 2px;
  transition: transform var(--transition-fast), opacity var(--transition-fast);
}

.nav-toggle[aria-expanded="true"] span:nth-child(1) {
  transform: translateY(6px) rotate(45deg);
}

.nav-toggle[aria-expanded="true"] span:nth-child(2) {
  opacity: 0;
}

.nav-toggle[aria-expanded="true"] span:nth-child(3) {
  transform: translateY(-6px) rotate(-45deg);
}

@media (max-width: 767px) {
  .nav {
    position: fixed;
    inset: var(--header-height) 0 auto 0;
    flex-direction: column;
    align-items: flex-start;
    gap: 0;
    padding: var(--space-2) var(--space-3) var(--space-3);
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    transform: translateY(-8px);
    opacity: 0;
    visibility: hidden;
    pointer-events: none;
    transition: transform var(--transition-base), opacity var(--transition-base), visibility var(--transition-base);
  }

  .nav a {
    width: 100%;
    padding: var(--space-2) 0;
    border-bottom: 1px solid var(--color-border);
  }

  .nav.is-open {
    transform: translateY(0);
    opacity: 1;
    visibility: visible;
    pointer-events: auto;
  }
}

@media (min-width: 768px) {
  .nav {
    display: flex;
  }

  .nav-toggle {
    display: none;
  }

  .header__actions .btn--primary {
    display: inline-flex;
  }
}

/* Hero ---------------------------------------------------------------------- */

.hero {
  position: relative;
  padding: var(--space-6) 0 var(--space-7);
  overflow: hidden;
}

.hero__bg {
  position: absolute;
  inset: 0;
  z-index: -1;
}

.hero__blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  opacity: 0.35;
}

.hero__blob--a {
  width: 420px;
  height: 420px;
  top: -120px;
  left: -100px;
  background: var(--color-accent);
}

.hero__blob--b {
  width: 380px;
  height: 380px;
  top: 40px;
  right: -140px;
  background: var(--color-accent-2);
}

@media (prefers-reduced-motion: no-preference) {
  .hero__blob {
    animation: drift 16s ease-in-out infinite alternate;
  }

  .hero__blob--b {
    animation-duration: 20s;
    animation-direction: alternate-reverse;
  }
}

@keyframes drift {
  from { transform: translate(0, 0) scale(1); }
  to { transform: translate(30px, 40px) scale(1.08); }
}

.hero__inner {
  display: flex;
  flex-direction: column;
  gap: var(--space-6);
}

.hero__copy {
  text-align: center;
}

.hero__title {
  font-size: clamp(2.25rem, 7vw, 3.75rem);
  letter-spacing: -0.03em;
}

.hero__subtitle {
  margin-top: var(--space-2);
  font-size: 1.125rem;
  color: var(--color-text-secondary);
  max-width: 520px;
  margin-left: auto;
  margin-right: auto;
}

.hero__cta {
  margin-top: var(--space-4);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  align-items: center;
}

.hero__visual {
  display: flex;
  justify-content: center;
}

@media (min-width: 1024px) {
  .hero__inner {
    flex-direction: row;
    align-items: center;
    text-align: left;
  }

  .hero__copy {
    text-align: left;
    flex: 1;
  }

  .hero__subtitle {
    margin-left: 0;
  }

  .hero__cta {
    flex-direction: row;
    justify-content: flex-start;
  }

  .hero__visual {
    flex: 1;
  }
}

/* EDMS mockup window ------------------------------------------------------- */

.edms-window {
  width: 100%;
  max-width: 420px;
  background: var(--color-surface-2);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
}

.edms-window__bar {
  display: flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-2) var(--space-3);
  border-bottom: 1px solid var(--color-border);
}

.dot {
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--color-border-strong);
}

.dot--a { background: #ff5f57; }
.dot--b { background: #febc2e; }
.dot--c { background: #28c840; }

.edms-window__title {
  margin-left: var(--space-2);
  font-size: 0.8125rem;
  font-weight: 500;
  color: var(--color-text-secondary);
}

.edms-window__body {
  padding: var(--space-3);
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.edms-row {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  background: var(--color-surface);
}

.edms-row__icon {
  width: 18px;
  height: 18px;
  color: var(--color-text-secondary);
  flex-shrink: 0;
}

.edms-row__name {
  flex: 1;
  font-size: 0.8125rem;
  font-weight: 500;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.edms-progress {
  margin-top: var(--space-1);
}

.edms-progress__label {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-1);
}

.edms-progress__track {
  height: 6px;
  border-radius: var(--radius-full);
  background: var(--color-border);
  overflow: hidden;
}

.edms-progress__fill {
  height: 100%;
  width: 72%;
  border-radius: var(--radius-full);
  background: var(--gradient-brand);
}

/* Pills ---------------------------------------------------------------------- */

.pill {
  display: inline-flex;
  align-items: center;
  padding: 4px 10px;
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  white-space: nowrap;
}

.pill--approved { background: var(--color-success-bg); color: var(--color-success-text); }
.pill--review { background: var(--color-warning-bg); color: var(--color-warning-text); }
.pill--draft { background: var(--color-neutral-bg); color: var(--color-neutral-text); }
.pill--soon { background: var(--color-neutral-bg); color: var(--color-neutral-text); }
.pill--popular {
  background: var(--gradient-brand);
  color: var(--color-accent-contrast);
  position: absolute;
  top: -12px;
  left: 50%;
  transform: translateX(-50%);
}

/* Cards ------------------------------------------------------------------ */

.card-grid {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: 1fr;
}

@media (min-width: 768px) {
  .card-grid--3 {
    grid-template-columns: repeat(3, 1fr);
  }
}

.card {
  padding: var(--space-4);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  transition: transform var(--transition-base), box-shadow var(--transition-base), border-color var(--transition-base);
}

.card:hover {
  transform: translateY(-4px);
  box-shadow: var(--shadow-md);
  border-color: var(--color-border-strong);
}

.card__icon {
  width: 44px;
  height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-radius: var(--radius-sm);
  background: var(--gradient-brand);
  color: #fff;
  margin-bottom: var(--space-3);
}

.card__icon svg {
  width: 22px;
  height: 22px;
}

.card h3 {
  font-size: 1.125rem;
  margin-bottom: var(--space-1);
}

.card p {
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
}

.card--upcoming .pill--soon {
  margin-bottom: var(--space-2);
}

/* Why section ------------------------------------------------------------ */

.why__inner {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
}

.why__grid {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: 1fr;
}

.why__item {
  padding: var(--space-3);
  border-left: 2px solid var(--color-accent);
}

.why__item h4 {
  font-size: 1.0625rem;
  margin-bottom: var(--space-1);
}

.why__item p {
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
}

@media (min-width: 768px) {
  .why__inner {
    flex-direction: row;
    align-items: flex-start;
  }

  .why__copy,
  .why__grid {
    flex: 1;
  }
}

/* Featured course ---------------------------------------------------------- */

.course-spotlight {
  display: grid;
  gap: var(--space-4);
  padding: var(--space-4);
  border-radius: var(--radius-lg);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
}

.course-spotlight__visual {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 160px;
  border-radius: var(--radius-md);
  background: var(--gradient-brand);
  color: #fff;
}

.course-spotlight__visual svg {
  width: 64px;
  height: 64px;
}

.course-spotlight__body .tag {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--color-accent);
  margin-bottom: var(--space-1);
}

.course-spotlight__body h3 {
  font-size: 1.375rem;
  margin-bottom: var(--space-1);
}

.course-spotlight__body p {
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2);
}

.meta-list {
  display: flex;
  flex-wrap: wrap;
  gap: var(--space-1) var(--space-3);
  font-size: 0.8125rem;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-3);
}

.meta-list li::before {
  content: "•";
  margin-right: 6px;
  color: var(--color-accent);
}

@media (min-width: 768px) {
  .course-spotlight {
    grid-template-columns: 1fr 1.4fr;
    align-items: center;
  }
}

/* Pricing ------------------------------------------------------------------ */

.pricing-grid {
  display: grid;
  gap: var(--space-3);
  grid-template-columns: 1fr;
}

.price-card {
  position: relative;
  padding: var(--space-4);
  border-radius: var(--radius-md);
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  display: flex;
  flex-direction: column;
}

.price-card--featured {
  background: var(--color-surface-2);
  border-color: var(--color-accent);
  box-shadow: var(--shadow-lg);
}

.price-card h3 {
  font-size: 1.125rem;
}

.price-card__price {
  font-size: 2.25rem;
  font-weight: 700;
  letter-spacing: -0.02em;
  margin-top: var(--space-1);
}

.price-card__price span {
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text-secondary);
}

.price-card__desc {
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
  margin-top: var(--space-1);
  margin-bottom: var(--space-3);
}

.price-card__features {
  display: flex;
  flex-direction: column;
  gap: var(--space-1);
  font-size: 0.9375rem;
  margin-bottom: var(--space-4);
  flex: 1;
}

.price-card__features li {
  padding-left: var(--space-3);
  position: relative;
}

.price-card__features li::before {
  content: "✓";
  position: absolute;
  left: 0;
  color: var(--color-accent);
  font-weight: 700;
}

@media (min-width: 960px) {
  .pricing-grid {
    grid-template-columns: repeat(3, 1fr);
    align-items: stretch;
  }

  .price-card--featured {
    transform: scale(1.03);
  }
}

/* FAQ ------------------------------------------------------------------ */

.faq-list {
  max-width: 720px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.faq-item {
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
  background: var(--color-surface);
}

.faq-item__question {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--space-2);
  padding: var(--space-3);
  text-align: left;
  font-weight: 600;
  font-size: 0.9375rem;
}

.faq-item__icon {
  width: 18px;
  height: 18px;
  flex-shrink: 0;
  transition: transform var(--transition-base);
}

.faq-item__question[aria-expanded="true"] .faq-item__icon {
  transform: rotate(180deg);
}

.faq-item__answer {
  max-height: 0;
  overflow: hidden;
  transition: max-height var(--transition-base);
}

.faq-item__answer p {
  padding: 0 var(--space-3) var(--space-3);
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
}

/* Footer ------------------------------------------------------------------ */

.site-footer {
  border-top: 1px solid var(--color-border);
  padding-top: var(--space-6);
}

.footer__inner {
  display: flex;
  flex-direction: column;
  gap: var(--space-5);
  padding-bottom: var(--space-5);
}

.footer__brand p {
  margin-top: var(--space-1);
  color: var(--color-text-secondary);
  font-size: 0.9375rem;
  max-width: 320px;
}

.footer__links {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-3);
}

.footer__col h5 {
  font-size: 0.8125rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--color-text-secondary);
  margin-bottom: var(--space-2);
}

.footer__col a {
  display: block;
  padding: 6px 0;
  font-size: 0.9375rem;
  color: var(--color-text-secondary);
  transition: color var(--transition-fast);
}

.footer__col a:hover {
  color: var(--color-text);
}

.footer__bottom {
  padding: var(--space-3) 0;
  border-top: 1px solid var(--color-border);
  color: var(--color-text-secondary);
  font-size: 0.8125rem;
}

@media (min-width: 768px) {
  .footer__inner {
    flex-direction: row;
    justify-content: space-between;
  }

  .footer__links {
    flex-shrink: 0;
  }
}