/* The Study Aid — marketing site custom styles
   Tailwind (CDN/Play) handles utility classes; this file holds things
   Tailwind can't express: keyframe animations, gradient blobs, the page
   transition curtain, and small bespoke components. */

:root {
  --brand-50: #f1faf3;
  --brand-100: #dcf3e2;
  --brand-200: #b8e6c6;
  --brand-300: #8ad4a2;
  --brand-400: #57ba78;
  --brand-500: #349c58;
  --brand-600: #237f45;
  --brand-700: #1c6538;
  --brand-800: #19512f;
  --brand-900: #164329;
  --brand-glow: rgba(52, 156, 88, 0.35);
}

html {
  scroll-behavior: smooth;
}

html.dark {
  color-scheme: dark;
}

body {
  font-family: "Inter", ui-sans-serif, system-ui, -apple-system, sans-serif;
  background-color: #fbfdfc;
}

html.dark body {
  background-color: #0b1410;
}

/* ---------- Page transition curtain ---------- */
#page-curtain {
  position: fixed;
  inset: 0;
  z-index: 9999;
  pointer-events: none;
  background: linear-gradient(135deg, var(--brand-600), var(--brand-400));
  opacity: 0;
  transform: translateY(0);
}

body.is-leaving #page-curtain {
  animation: curtain-in 0.45s ease forwards;
  pointer-events: all;
}

body.is-entering #page-curtain {
  animation: curtain-out 0.5s ease forwards;
  pointer-events: none;
}

@keyframes curtain-in {
  from { opacity: 0; clip-path: circle(0% at var(--cx, 50%) var(--cy, 50%)); }
  to { opacity: 1; clip-path: circle(150% at var(--cx, 50%) var(--cy, 50%)); }
}

@keyframes curtain-out {
  from { opacity: 1; }
  to { opacity: 0; }
}

main {
  animation: page-fade-in 0.55s ease both;
}

@keyframes page-fade-in {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

/* ---------- Animated gradient blobs ---------- */
.blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(60px);
  opacity: 0.55;
  will-change: transform;
}

.blob-float-1 { animation: float-1 14s ease-in-out infinite; }
.blob-float-2 { animation: float-2 18s ease-in-out infinite; }
.blob-float-3 { animation: float-3 16s ease-in-out infinite; }

@keyframes float-1 {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(40px, -30px) scale(1.08); }
}
@keyframes float-2 {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(-50px, 30px) scale(0.95); }
}
@keyframes float-3 {
  0%, 100% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(25px, 40px) scale(1.1); }
}

/* ---------- Nav underline ---------- */
.nav-link {
  position: relative;
}
.nav-link::after {
  content: "";
  position: absolute;
  left: 0;
  bottom: -4px;
  height: 2px;
  width: 0%;
  background: var(--brand-500);
  transition: width 0.25s ease;
}
.nav-link:hover::after,
.nav-link.active::after {
  width: 100%;
}
.nav-link.active {
  color: var(--brand-600);
}
html.dark .nav-link.active {
  color: var(--brand-300);
}

/* ---------- Buttons ---------- */
.btn-glow {
  position: relative;
  overflow: hidden;
  transition: transform 0.25s ease, box-shadow 0.25s ease;
}
.btn-glow:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 30px -8px var(--brand-glow);
}
.btn-glow:active {
  transform: translateY(0px) scale(0.98);
}

/* ---------- Feature / tier cards ---------- */
.tilt-card {
  transition: transform 0.35s cubic-bezier(.22,1,.36,1), box-shadow 0.35s ease;
  transform-style: preserve-3d;
}
.tilt-card:hover {
  box-shadow: 0 24px 48px -16px rgba(16, 60, 34, 0.25);
}

html.dark .tilt-card:hover {
  box-shadow: 0 24px 48px -16px rgba(0, 0, 0, 0.6);
}

/* ---------- Marquee (language strip) ---------- */
.marquee-track {
  display: flex;
  width: max-content;
  animation: marquee 28s linear infinite;
}
.marquee-track:hover {
  animation-play-state: paused;
}
@keyframes marquee {
  from { transform: translateX(0); }
  to { transform: translateX(-50%); }
}

/* ---------- FAQ accordion ---------- */
.faq-item[data-open="true"] .faq-answer {
  grid-template-rows: 1fr;
  opacity: 1;
}
.faq-answer {
  display: grid;
  grid-template-rows: 0fr;
  opacity: 0;
  transition: grid-template-rows 0.35s ease, opacity 0.3s ease;
}
.faq-answer > div {
  overflow: hidden;
}
.faq-item .chevron {
  transition: transform 0.3s ease;
}
.faq-item[data-open="true"] .chevron {
  transform: rotate(180deg);
}

/* ---------- Mobile menu ---------- */
#mobile-menu {
  transition: max-height 0.4s ease, opacity 0.3s ease;
  max-height: 0;
  opacity: 0;
  overflow: hidden;
}
#mobile-menu.open {
  max-height: 600px;
  opacity: 1;
}

/* ---------- Device mockup frame ---------- */
.device-frame {
  transition: transform 0.4s cubic-bezier(.22,1,.36,1);
}
.device-frame:hover {
  transform: translateY(-6px) rotate(0deg) scale(1.02);
}

/* ---------- Back to top ---------- */
#back-to-top {
  transition: opacity 0.3s ease, transform 0.3s ease;
  opacity: 0;
  transform: translateY(12px);
  pointer-events: none;
}
#back-to-top.visible {
  opacity: 1;
  transform: translateY(0);
  pointer-events: all;
}

/* ---------- Tier badge shine ---------- */
.gold-shine {
  position: relative;
  overflow: hidden;
}
.gold-shine::before {
  content: "";
  position: absolute;
  top: 0;
  left: -75%;
  width: 50%;
  height: 100%;
  background: linear-gradient(120deg, transparent, rgba(255,255,255,0.55), transparent);
  transform: skewX(-20deg);
  animation: shine 4.5s ease-in-out infinite;
}
@keyframes shine {
  0% { left: -75%; }
  40%, 100% { left: 130%; }
}

::selection {
  background: var(--brand-300);
  color: #0b1410;
}

/* scrollbar (webkit) */
::-webkit-scrollbar { width: 10px; height: 10px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--brand-300); border-radius: 999px; }
html.dark ::-webkit-scrollbar-thumb { background: var(--brand-700); }