/* ==========================================================================
   Design system — typography, palette, spacing
   ========================================================================== */
:root {
  /* Colors — Telegram-ish blues, professional */
  --color-primary: #0d6efd;
  --color-primary-deep: #0a58ca;
  --color-accent: #6ea8fe;
  --color-background: #f8fafc;
  --color-background-gradient: linear-gradient(180deg, #f1f5f9 0%, #e2e8f0 100%);
  --color-card: #ffffff;
  --color-text: #0f172a;
  --color-text-muted: #64748b;
  --color-border: #e2e8f0;
  --color-border-strong: #cbd5e1;
  --color-error: #dc2626;
  --color-success: #16a34a;

  /* Typography */
  --font-family-base: "Inter", system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-size-base: 1rem;
  --font-size-sm: 0.875rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.25rem;
  --font-size-2xl: 1.5rem;
  --font-size-3xl: 2rem;
  --font-size-hero: clamp(2rem, 5vw, 3.5rem);
  --font-weight-normal: 400;
  --font-weight-medium: 500;
  --font-weight-semibold: 600;
  --font-weight-bold: 700;
  --line-height-tight: 1.25;
  --line-height-normal: 1.5;
  --line-height-relaxed: 1.6;

  /* Spacing */
  --section-padding-y: clamp(2.5rem, 5vw, 6rem);
  --section-padding-x: clamp(1.25rem, 4vw, 3rem);
  --content-max: 1200px;
  --radius: 12px;
  --radius-lg: 16px;
  --shadow: 0 1px 3px rgba(0, 0, 0, 0.06);
  --shadow-md: 0 4px 12px rgba(0, 0, 0, 0.08);
  --shadow-lg: 0 10px 40px rgba(0, 0, 0, 0.1);
}

/* Base */
html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-normal);
  line-height: var(--line-height-relaxed);
  color: var(--color-text);
  background: var(--color-background);
  margin: 0;
  min-height: 100vh;
}

h1, h2, h3 {
  font-weight: var(--font-weight-bold);
  line-height: var(--line-height-tight);
  margin: 0 0 0.5em;
}

h1 { font-size: var(--font-size-3xl); }
h2 { font-size: var(--font-size-2xl); }
h3 { font-size: var(--font-size-xl); }

p {
  margin: 0 0 1em;
}

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

a:hover {
  text-decoration: underline;
}

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

/* ==========================================================================
   Nav
   ========================================================================== */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(255, 255, 255, 0.9);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--color-border);
}

.nav__inner {
  max-width: var(--content-max);
  margin: 0 auto;
  padding: 0.75rem var(--section-padding-x);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
}

.nav__logo {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-lg);
  color: var(--color-text);
  text-decoration: none;
}

.nav__logo:hover {
  text-decoration: none;
  color: var(--color-primary);
}

.nav__logo-icon {
  font-size: 1.25rem;
  color: var(--color-primary);
}

.nav__links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem 1.5rem;
}

.nav__links a {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text-muted);
}

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

.nav__link--muted {
  opacity: 0.8;
}

/* ==========================================================================
   Hero
   ========================================================================== */
.hero {
  display: flex;
  align-items: center;
  padding: clamp(1.5rem, 3vw, 2.5rem) var(--section-padding-x);
  background: var(--color-background-gradient);
}

.hero__inner {
  max-width: var(--content-max);
  margin: 0 auto;
  width: 100%;
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.hero__copy {
  max-width: 36rem;
}

.hero__form-wrap {
  min-width: 0;
}

.hero__badge {
  display: inline-block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-success);
  background: rgba(22, 163, 74, 0.12);
  padding: 0.25rem 0.75rem;
  border-radius: 999px;
  margin-bottom: 1rem;
}

.hero__title {
  font-size: var(--font-size-hero);
  font-weight: var(--font-weight-bold);
  color: var(--color-text);
  margin-bottom: 0.75rem;
  line-height: 1.2;
}

.hero__subtitle {
  font-size: clamp(1rem, 2vw, 1.125rem);
  color: var(--color-text-muted);
  margin: 0 0 0.5rem;
  line-height: 1.6;
}

.hero__support {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 0 0 0;
}

/* Hero form */
.hero__form {
  margin-top: 0;
}

.hero__form-label {
  display: block;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.hero__input-wrap {
  display: flex;
  align-items: center;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.hero__input-wrap:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(13, 110, 253, 0.2);
}

.hero__input-icon {
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 1rem;
  color: var(--color-text-muted);
}

.hero__input {
  flex: 1;
  min-width: 0;
  height: 52px;
  padding: 0 1rem 0 0;
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  border: none;
  color: var(--color-text);
  background: transparent;
}

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

.hero__input:focus {
  outline: none;
}

.hero__input-wrap.has-error {
  border-color: var(--color-error);
}

.hero__hint {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 0.5rem 0 0;
}

.hero__error {
  font-size: var(--font-size-sm);
  color: var(--color-error);
  margin: 0.5rem 0 0;
  min-height: 1.25rem;
}

.hero__error:not(:empty) {
  display: block;
}

.hero__actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.75rem;
  margin-top: 1rem;
}

.hero__cta {
  position: relative;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  min-height: 48px;
  margin-top: 1rem;
  padding: 0 1.5rem;
  font-family: var(--font-family-base);
  font-size: var(--font-size-base);
  font-weight: var(--font-weight-semibold);
  border: none;
  border-radius: var(--radius);
  background: var(--color-primary);
  color: #fff;
  cursor: pointer;
  transition: background 0.2s;
  overflow: hidden;
}

.hero__cta-progress {
  position: absolute;
  left: 0;
  top: 0;
  height: 100%;
  width: var(--progress, 0%);
  background: var(--color-primary-deep);
  border-radius: var(--radius) 0 0 var(--radius);
  transition: width 0.08s linear;
  pointer-events: none;
}

.hero__cta .hero__cta-text,
.hero__cta .hero__cta-loading {
  position: relative;
  z-index: 1;
}

.hero__cta:hover {
  background: var(--color-primary-deep);
}

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

.hero__cta[aria-busy="true"] {
  background: var(--color-primary);
}

.hero__cta[aria-busy="true"] .hero__cta-text {
  display: none;
}

.hero__cta[aria-busy="true"] .hero__cta-loading {
  display: inline;
}

.hero__cta-loading {
  display: none;
}

/* Result panel */
.hero__result {
  margin-top: 1.5rem;
  padding: 1.25rem;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.hero__result[hidden] {
  display: none !important;
}

.result__message {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 0 0 0.75rem;
}

.result__url-row {
  display: flex;
  gap: 0.5rem;
}

.result__note {
  font-size: var(--font-size-xs, 0.8125rem);
  color: var(--color-text-muted);
  margin: 0.75rem 0 0;
}

.result__url {
  flex: 1;
  min-width: 0;
  padding: 0.5rem 0.75rem;
  font-size: var(--font-size-sm);
  font-family: var(--font-family-base);
  border: 1px solid var(--color-border);
  border-radius: var(--radius);
  background: var(--color-background);
  color: var(--color-text);
}

.result__copy {
  flex-shrink: 0;
  padding: 0.5rem 1rem;
  font-family: var(--font-family-base);
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  border: 1px solid var(--color-primary);
  border-radius: var(--radius);
  background: var(--color-primary);
  color: #fff;
  cursor: pointer;
  white-space: nowrap;
}

.result__copy:hover {
  background: var(--color-primary-deep);
  border-color: var(--color-primary-deep);
}

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

/* ==========================================================================
   Trust row
   ========================================================================== */
.trust {
  padding: clamp(1.5rem, 3vw, 2.5rem) var(--section-padding-x);
  background: linear-gradient(180deg, var(--color-card) 0%, #f8fafc 100%);
  border-bottom: 1px solid var(--color-border);
}

.trust__inner {
  max-width: var(--content-max);
  margin: 0 auto;
  text-align: center;
}

.trust__headline {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin: 0 0 1rem;
}

.trust__list {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.5rem 0.75rem;
  list-style: none;
  margin: 0;
  padding: 0;
}

.trust__item {
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  padding: 0.4rem 0.75rem;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  color: var(--color-text);
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: 999px;
  box-shadow: var(--shadow);
}

.trust__icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  color: var(--color-primary);
}

/* ==========================================================================
   Section layout
   ========================================================================== */
.section {
  padding: var(--section-padding-y) var(--section-padding-x);
}

.section__inner {
  max-width: var(--content-max);
  margin: 0 auto;
}

.section__inner--legal {
  max-width: 52rem;
}

.section__inner--split {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 3rem;
  align-items: center;
}

.section__title {
  text-align: center;
  margin-bottom: 2rem;
}

.legal__title {
  text-align: left;
  margin-bottom: 1rem;
}

.legal h2 {
  margin-top: 1.75rem;
}

.legal h3 {
  margin-top: 1.25rem;
}

.legal ul,
.legal ol {
  padding-left: 1.25rem;
  margin: 0 0 1em;
}

.legal li {
  margin: 0.25rem 0;
}

.section__footnote {
  text-align: center;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 1.5rem 0 0;
}

/* ==========================================================================
   Features grid
   ========================================================================== */
.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 1.5rem;
}

.feature {
  padding: 1.5rem;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow);
}

.feature__icon {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 2.5rem;
  height: 2.5rem;
  margin-bottom: 0.75rem;
  color: var(--color-primary);
}

.feature__icon svg {
  width: 24px;
  height: 24px;
}

.feature__title {
  font-size: var(--font-size-lg);
  margin-bottom: 0.35rem;
}

.feature__desc {
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 0;
}

/* ==========================================================================
   How it works (steps)
   ========================================================================== */
.steps__content .section__title {
  text-align: left;
  margin-bottom: 1.5rem;
}

.steps {
  list-style: none;
  padding: 0;
  margin: 0;
}

.step {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
  margin-bottom: 1.25rem;
}

.step__num {
  flex-shrink: 0;
  width: 2rem;
  height: 2rem;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: var(--font-weight-bold);
  font-size: var(--font-size-sm);
  background: var(--color-primary);
  color: #fff;
  border-radius: 50%;
}

.step__text {
  margin: 0.25rem 0 0;
  font-size: var(--font-size-lg);
}

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

.steps__diagram {
  display: flex;
  align-items: center;
  gap: 1rem;
  padding: 1.5rem 2rem;
  background: var(--color-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-md);
}

.diagram__box {
  padding: 0.5rem 1rem;
  font-size: var(--font-size-sm);
  background: var(--color-background);
  border-radius: var(--radius);
}

.diagram__box--rss {
  background: var(--color-primary);
  color: #fff;
}

.diagram__arrow {
  font-size: 1.25rem;
  color: var(--color-text-muted);
}

/* ==========================================================================
   Donate
   ========================================================================== */
.section--donate {
  background: var(--color-card);
  border-top: 1px solid var(--color-border);
}

.donate__copy {
  max-width: 42rem;
  margin: 0 auto 2rem;
  text-align: center;
  color: var(--color-text-muted);
}

.donate__cards {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 1.5rem;
  max-width: 36rem;
  margin: 0 auto 2rem;
}

.donate__card {
  padding: 1.5rem;
  border-radius: var(--radius-lg);
  border: 1px solid var(--color-border);
  background: var(--color-background);
}

.donate__card--us {
  border-color: var(--color-primary);
  background: linear-gradient(180deg, rgba(13, 110, 253, 0.06) 0%, var(--color-card) 100%);
}

.donate__card-label {
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-semibold);
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--color-text-muted);
  margin: 0 0 0.5rem;
}

.donate__card--us .donate__card-label {
  color: var(--color-primary);
}

.donate__card-price {
  font-size: var(--font-size-2xl);
  font-weight: var(--font-weight-bold);
  margin: 0 0 1rem;
  color: var(--color-text);
}

.donate__card-price--suggested {
  color: var(--color-primary);
}

.donate__card-list {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--color-text-muted);
  font-size: var(--font-size-sm);
  line-height: 1.6;
}

.donate__card-list li {
  margin-bottom: 0.35rem;
}

.donate__card-list li:last-child {
  margin-bottom: 0;
}

.donate__actions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.75rem;
  margin-bottom: 0.75rem;
}

.donate__cta {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  padding: 0 1.5rem;
  font-weight: var(--font-weight-semibold);
  background: var(--color-primary);
  color: #fff;
  border-radius: var(--radius);
  text-decoration: none;
}

.donate__cta:hover {
  text-decoration: none;
  background: var(--color-primary-deep);
}

.donate__secondary {
  display: inline-flex;
  align-items: center;
  min-height: 48px;
  padding: 0 1rem;
  font-weight: var(--font-weight-medium);
  color: var(--color-primary);
  border: 1px solid var(--color-border-strong);
  border-radius: var(--radius);
  text-decoration: none;
}

.donate__secondary:hover {
  text-decoration: none;
  background: var(--color-background);
}

.donate__trust {
  text-align: center;
  font-size: var(--font-size-sm);
  color: var(--color-text-muted);
  margin: 0;
}

/* ==========================================================================
   FAQ
   ========================================================================== */
.faq {
  max-width: 40rem;
  margin: 0 auto;
}

.faq__item {
  margin-bottom: 1.25rem;
  padding-bottom: 1.25rem;
  border-bottom: 1px solid var(--color-border);
}

.faq__item:last-of-type {
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.faq__q {
  font-weight: var(--font-weight-semibold);
  font-size: var(--font-size-lg);
  margin: 0 0 0.35rem;
}

.faq__a {
  margin: 0;
  font-size: var(--font-size-base);
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* ==========================================================================
   Footer
   ========================================================================== */
.footer {
  padding: 2rem var(--section-padding-x);
  background: var(--color-text);
  color: #94a3b8;
}

.footer__inner {
  max-width: var(--content-max);
  margin: 0 auto;
  text-align: center;
}

.footer__status {
  font-size: var(--font-size-sm);
  color: #64748b;
  margin: 0 0 0.5rem;
}

.footer__links {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem 1.5rem;
  margin-bottom: 0.75rem;
}

.footer__links a {
  color: #94a3b8;
  font-size: var(--font-size-sm);
}

.footer__links a:hover {
  color: #fff;
  text-decoration: none;
}

.footer__copy {
  font-size: var(--font-size-sm);
  margin: 0;
  opacity: 0.9;
}

/* ==========================================================================
   Toast
   ========================================================================== */
.toast {
  position: fixed;
  bottom: 1.5rem;
  left: 50%;
  transform: translateX(-50%) translateY(1rem);
  padding: 0.5rem 1rem;
  background: var(--color-text);
  color: #fff;
  font-size: var(--font-size-sm);
  font-weight: var(--font-weight-medium);
  border-radius: var(--radius);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  transition: opacity 0.2s, transform 0.2s;
  pointer-events: none;
}

.toast[data-visible="true"] {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.toast[hidden] {
  display: none !important;
}

/* ==========================================================================
   Responsive
   ========================================================================== */
@media (max-width: 900px) {
  .hero__inner {
    grid-template-columns: 1fr;
    gap: 2rem;
    text-align: center;
  }

  .hero__copy {
    max-width: none;
  }

  .hero__form-wrap {
    max-width: 28rem;
    margin: 0 auto;
  }

  .hero__form-label {
    text-align: left;
  }

  .hero__badge {
    margin-bottom: 0.75rem;
  }

  .section__inner--split {
    grid-template-columns: 1fr;
  }

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

  .steps__visual {
    order: -1;
  }

  .features {
    grid-template-columns: repeat(2, 1fr);
  }
}

@media (max-width: 600px) {
  .nav__links {
    display: none;
  }

  .hero {
    min-height: auto;
    max-height: none;
    padding-top: 2rem;
    padding-bottom: 2rem;
  }

  .hero__cta {
    width: 100%;
  }

  .result__url-row {
    flex-direction: column;
  }

  .features {
    grid-template-columns: 1fr;
  }

  .donate__cards {
    grid-template-columns: 1fr;
  }

  .steps__diagram {
    flex-direction: column;
  }
}

/* Focus visible for accessibility */
button:focus-visible,
input:focus-visible {
  outline: 2px solid var(--color-primary);
  outline-offset: 2px;
}