/* BurnRate - Design System */
:root {
  --color-bg: #fff;
  --color-bg-footer: #f5f5f5;
  --color-text: #1a1a1a;
  --color-text-muted: #666;
  --color-accent-start: #E8772E;
  --color-accent-end: #F5A623;
  --color-border: #e5e5e5;
  --color-border-light: #eee;
  --max-width: 960px;
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  --spacing-2xl: 4rem;
  --radius-sm: 6px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --shadow-card: 0 2px 16px rgba(0, 0, 0, 0.07);
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --nav-height: 64px;
}

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

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font-sans);
  font-size: 16px;
  line-height: 1.6;
  color: var(--color-text);
  background: var(--color-bg);
}

img {
  max-width: 100%;
  height: auto;
}

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

/* Layout */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 var(--spacing-md);
}

/* Nav — logo + brand left, hamburger right */
.nav {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: var(--nav-height);
  padding: 0 var(--spacing-lg);
  background: var(--color-bg);
  border-bottom: 1px solid var(--color-border-light);
  transition: background 0.3s ease, backdrop-filter 0.3s ease, border-color 0.3s ease;
}

/* Liquid glass effect when scrolled */
.nav--glass {
  background: rgba(255, 255, 255, 0.72);
  backdrop-filter: blur(20px) saturate(180%);
  -webkit-backdrop-filter: blur(20px) saturate(180%);
  border-bottom-color: rgba(0, 0, 0, 0.08);
}

/* Logo + brand together on the left */
.nav__left {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  text-decoration: none;
  color: inherit;
}

.nav__logo-img {
  width: 30px;
  height: 30px;
  object-fit: contain;
}

.nav__brand {
  font-weight: 700;
  font-size: 1.125rem;
  color: #555;
}

.nav__links {
  display: flex;
  align-items: center;
  gap: var(--spacing-lg);
}

.nav__links a {
  font-size: 0.9375rem;
  color: var(--color-text);
  transition: color 0.2s;
}

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

.nav__cta {
  display: inline-flex;
  align-items: center;
  padding: var(--spacing-xs) var(--spacing-md);
  background: linear-gradient(135deg, var(--color-accent-start), var(--color-accent-end));
  color: white !important;
  font-weight: 600;
  font-size: 0.9375rem;
  border-radius: var(--radius-full);
  border: none;
  cursor: pointer;
  transition: opacity 0.2s;
}

.nav__cta:hover {
  opacity: 0.9;
}

.nav__hamburger {
  display: none;
  background: none;
  border: none;
  padding: 0.5rem;
  cursor: pointer;
  flex-shrink: 0;
}

.nav__hamburger svg {
  width: 22px;
  height: 22px;
  display: block;
}

/* Hero (Homepage) */
.hero {
  text-align: center;
  padding: var(--spacing-2xl) var(--spacing-md) var(--spacing-xl);
}

.hero__logo {
  width: 160px;
  height: 160px;
  object-fit: contain;
  margin: 0 auto var(--spacing-lg);
  display: block;
}

.hero__title {
  font-size: 2.75rem;
  font-weight: 700;
  margin: 0 0 var(--spacing-sm);
  letter-spacing: -0.02em;
}

.hero__subtitle {
  font-size: 1.625rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--spacing-lg);
  font-weight: 400;
}

.hero__cta {
  display: inline-flex;
  align-items: center;
  padding: 0.75rem var(--spacing-xl);
  background: linear-gradient(135deg, var(--color-accent-start), var(--color-accent-end));
  color: white;
  font-weight: 600;
  font-size: 1rem;
  border-radius: var(--radius-full);
  border: none;
  cursor: pointer;
  transition: opacity 0.2s;
}

.hero__cta:hover {
  opacity: 0.9;
}

/* Phone mockup */
.phone-mockup {
  display: block;
  margin: 0 auto var(--spacing-2xl);
  max-width: 300px;
  width: 100%;
  height: auto;
  border-radius: 0;
  filter: drop-shadow(0 24px 48px rgba(0, 0, 0, 0.18));
}

/* Tagline section */
.tagline {
  text-align: center;
  padding: var(--spacing-2xl) var(--spacing-md);
  max-width: 700px;
  margin: 0 auto;
}

.tagline__text {
  font-size: 1.625rem;
  font-weight: 600;
  line-height: 1.45;
  color: var(--color-text);
  margin: 0;
}

/* Feature cards — sticky stack */
.features {
  padding: 0 0 var(--spacing-2xl);
}

.features .container {
  /* Each card needs room for sticky positioning within this container */
}

.feature-card {
  background: var(--color-bg);
  border: 1px solid #e8e8e8;
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl) var(--spacing-xl) var(--spacing-xl);
  margin: 0 var(--spacing-md) var(--spacing-lg);
  box-shadow: var(--shadow-card);
  max-width: var(--max-width);
  margin-left: auto;
  margin-right: auto;
}

/* Sticky stacking: each card sticks at an increasing top offset */
.feature-card--1 {
  position: sticky;
  top: calc(var(--nav-height) + 16px);
  z-index: 1;
}

.feature-card--2 {
  position: sticky;
  top: calc(var(--nav-height) + 32px);
  z-index: 2;
}

.feature-card--3 {
  position: sticky;
  top: calc(var(--nav-height) + 48px);
  z-index: 3;
}

.feature-card__icon {
  width: 52px;
  height: 52px;
  object-fit: contain;
  margin-bottom: var(--spacing-md);
  display: block;
}

.feature-card__title {
  font-size: 1.25rem;
  font-weight: 700;
  margin: 0 0 0.75rem;
}

.feature-card__desc {
  font-size: 0.9375rem;
  color: var(--color-text);
  margin: 0 0 var(--spacing-md);
  line-height: 1.65;
}

.feature-card__desc strong {
  color: var(--color-text);
  font-weight: 600;
}

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

.feature-card__list li {
  display: flex;
  align-items: flex-start;
  gap: 0.625rem;
  font-size: 0.9375rem;
  color: var(--color-text);
  margin-bottom: 0.5rem;
}

.feature-card__list li:last-child {
  margin-bottom: 0;
}

.feature-card__list .check {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  margin-top: 2px;
}

/* Feature grid (waitlist page) */
.features-grid {
  padding: var(--spacing-2xl) var(--spacing-md);
}

.features-grid .container {
  display: grid;
  grid-template-columns: 1fr;
  gap: var(--spacing-lg);
}

@media (min-width: 640px) {
  .features-grid .container {
    grid-template-columns: repeat(2, 1fr);
  }
}

.features-grid .feature-card {
  margin: 0;
  position: static;
}

/* FAQ */
.faq {
  padding: var(--spacing-2xl) var(--spacing-md);
}

.faq__title {
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 var(--spacing-xl);
  text-align: center;
}

.faq__list {
  max-width: 720px;
  margin: 0 auto;
  border-top: 1px solid var(--color-border);
}

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

.faq__item summary {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--spacing-md) 0;
  font-size: 1rem;
  font-weight: 500;
  color: var(--color-text);
  cursor: pointer;
  list-style: none;
  user-select: none;
}

.faq__item summary::-webkit-details-marker {
  display: none;
}

.faq__item summary::after {
  content: "";
  width: 20px;
  height: 20px;
  background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' fill='none' viewBox='0 0 24 24' stroke='%23666'%3E%3Cpath stroke-linecap='round' stroke-linejoin='round' stroke-width='2' d='M19 9l-7 7-7-7'/%3E%3C/svg%3E") no-repeat center;
  flex-shrink: 0;
  margin-left: var(--spacing-sm);
  transition: transform 0.2s;
}

.faq__item[open] summary::after {
  transform: rotate(180deg);
}

.faq__item p {
  margin: 0 0 var(--spacing-md);
  padding: 0 var(--spacing-md) var(--spacing-md) 0;
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  line-height: 1.6;
}

/* Waitlist hero */
.waitlist-hero {
  text-align: center;
  padding: var(--spacing-2xl) var(--spacing-md);
}

.waitlist-hero__icon {
  width: 80px;
  height: 80px;
  margin: 0 auto var(--spacing-lg);
}

.waitlist-hero__title {
  font-size: 2.5rem;
  font-weight: 700;
  margin: 0 0 var(--spacing-sm);
  letter-spacing: -0.02em;
}

.waitlist-hero__subtitle {
  font-size: 1.125rem;
  color: var(--color-text-muted);
  margin: 0 auto var(--spacing-xl);
  max-width: 480px;
}

.waitlist-form {
  display: flex;
  flex-wrap: wrap;
  gap: var(--spacing-sm);
  justify-content: center;
  max-width: 420px;
  margin: 0 auto;
}

.waitlist-form__input {
  flex: 1;
  min-width: 200px;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 1rem;
  font-family: inherit;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
}

.waitlist-form__input::placeholder {
  color: #999;
}

.waitlist-form__input:focus {
  outline: none;
  border-color: var(--color-accent-start);
}

.waitlist-form__btn {
  padding: var(--spacing-sm) var(--spacing-xl);
  background: linear-gradient(135deg, var(--color-accent-start), var(--color-accent-end));
  color: white;
  font-weight: 600;
  font-size: 1rem;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  transition: opacity 0.2s;
}

.waitlist-form__btn:hover {
  opacity: 0.9;
}

/* Footer */
.footer {
  background: var(--color-bg-footer);
  padding: var(--spacing-xl) var(--spacing-md);
  margin-top: var(--spacing-2xl);
}

.footer__inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: var(--spacing-md);
}

.footer__logo {
  display: flex;
  align-items: center;
  gap: var(--spacing-sm);
}

.footer__logo-img {
  width: 24px;
  height: 24px;
  object-fit: contain;
}

.footer__brand {
  font-weight: 700;
  font-size: 1rem;
}

.footer__copy {
  font-size: 0.875rem;
  color: var(--color-text-muted);
  margin: var(--spacing-xs) 0 0 0;
}

.footer__copy a {
  color: var(--color-text);
  text-decoration: underline;
}

.footer__copy a:hover {
  color: var(--color-accent-start);
}

/* Privacy / legal page */
.page-content {
  padding: var(--spacing-2xl) var(--spacing-md);
  max-width: 720px;
  margin: 0 auto;
}

.page-title {
  font-size: 2rem;
  font-weight: 700;
  margin: 0 0 var(--spacing-sm);
}

.policy-meta {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  margin: 0 0 var(--spacing-xl);
}

.page-content h2 {
  font-size: 1.25rem;
  font-weight: 700;
  margin: var(--spacing-xl) 0 var(--spacing-sm);
}

.page-content h3 {
  font-size: 1.0625rem;
  font-weight: 600;
  margin: var(--spacing-lg) 0 var(--spacing-xs);
}

.page-content p,
.page-content ul {
  font-size: 0.9375rem;
  line-height: 1.65;
  color: var(--color-text);
  margin: 0 0 var(--spacing-md);
}

.page-content ul {
  padding-left: 1.5rem;
}

/* Delete data — standalone page (no nav) */
.standalone-page {
  min-height: 100vh;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--spacing-lg);
}

.delete-data {
  width: 100%;
  max-width: 420px;
  text-align: center;
}

.delete-data__logo {
  display: inline-block;
  margin-bottom: var(--spacing-xl);
}

.delete-data__logo-img {
  width: 48px;
  height: 48px;
  object-fit: contain;
}

.delete-data__main {
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--spacing-xl);
  box-shadow: var(--shadow-card);
}

.delete-data__title {
  font-size: 1.5rem;
  font-weight: 700;
  margin: 0 0 var(--spacing-md);
  color: var(--color-text);
}

.delete-data__intro {
  font-size: 0.9375rem;
  color: var(--color-text-muted);
  line-height: 1.5;
  margin: 0 0 var(--spacing-lg);
  text-align: left;
}

.delete-data__app-name {
  font-size: 0.9375rem;
  color: var(--color-text);
  line-height: 1.5;
  margin: 0 0 var(--spacing-lg);
  text-align: left;
}

.delete-data__steps {
  margin-bottom: var(--spacing-lg);
  text-align: left;
}

.delete-data__steps-title {
  font-size: 1rem;
  font-weight: 700;
  margin: 0 0 var(--spacing-sm);
  color: var(--color-text);
}

.delete-data__steps-list {
  margin: 0 0 var(--spacing-md);
  padding-left: 1.25rem;
  font-size: 0.9375rem;
  line-height: 1.55;
  color: var(--color-text);
}

.delete-data__steps-list li {
  margin-bottom: 0.5rem;
}

.delete-data__data-info {
  margin-top: var(--spacing-xl);
  padding-top: var(--spacing-lg);
  border-top: 1px solid var(--color-border);
  text-align: left;
}

.delete-data__data-title {
  font-size: 1rem;
  font-weight: 700;
  margin: 0 0 var(--spacing-sm);
  color: var(--color-text);
}

.delete-data__data-intro,
.delete-data__data-kept,
.delete-data__retention {
  font-size: 0.9375rem;
  line-height: 1.55;
  color: var(--color-text);
  margin: 0 0 var(--spacing-sm);
}

.delete-data__data-list {
  margin: 0 0 var(--spacing-md);
  padding-left: 1.25rem;
  font-size: 0.9375rem;
  line-height: 1.5;
  color: var(--color-text);
}

.delete-data__data-list li {
  margin-bottom: 0.25rem;
}

.delete-data__form {
  text-align: left;
  margin-bottom: var(--spacing-md);
}

.delete-data__label {
  display: block;
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--color-text);
  margin-bottom: 0.375rem;
}

.delete-data__input {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 1rem;
  font-family: inherit;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  background: var(--color-bg);
  margin-bottom: var(--spacing-md);
}

.delete-data__input:focus {
  outline: none;
  border-color: var(--color-accent-start);
}

.delete-data__submit {
  width: 100%;
  padding: var(--spacing-sm) var(--spacing-md);
  font-size: 1rem;
  font-weight: 600;
  font-family: inherit;
  color: white;
  background: linear-gradient(135deg, var(--color-accent-start), var(--color-accent-end));
  border: none;
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: opacity 0.2s;
}

.delete-data__submit:hover {
  opacity: 0.9;
}

.delete-data__note {
  font-size: 0.8125rem;
  color: var(--color-text-muted);
  line-height: 1.5;
  margin: 0 0 var(--spacing-lg);
  text-align: left;
}

.delete-data__note a {
  color: var(--color-accent-start);
  text-decoration: underline;
}

.delete-data__success {
  text-align: left;
  margin-bottom: var(--spacing-lg);
  padding: var(--spacing-md) 0;
}

.delete-data__success-text {
  font-size: 0.9375rem;
  color: var(--color-text);
  line-height: 1.5;
  margin: 0;
}

.delete-data__back {
  margin: 0;
  font-size: 0.9375rem;
}

.delete-data__back a {
  color: var(--color-text-muted);
  text-decoration: none;
}

.delete-data__back a:hover {
  color: var(--color-accent-start);
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 768px) {
  .nav__links {
    display: none;
  }

  .nav__links.is-open {
    display: flex;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    flex-direction: column;
    background: var(--color-bg);
    padding: var(--spacing-md);
    border-bottom: 1px solid var(--color-border-light);
    z-index: 99;
  }

  .nav__hamburger {
    display: block;
  }

  .hero__title {
    font-size: 2rem;
  }

  .tagline__text {
    font-size: 1.25rem;
  }

  .footer__inner {
    flex-direction: column;
    align-items: flex-start;
  }
}