/* ============================================
   Future Reminder — styles.css
   Apple-inspired, dark/light, clean & minimal
   ============================================ */

@import url('https://fonts.googleapis.com/css2?family=SF+Pro+Display:wght@300;400;500;600;700&display=swap');

/* ── CSS Variables ── */
:root {
  --font-display: -apple-system, "SF Pro Display", "Helvetica Neue", sans-serif;
  --font-body: -apple-system, "SF Pro Text", "Helvetica Neue", sans-serif;

  /* Light mode */
  --bg: #ffffff;
  --bg-secondary: #f5f5f7;
  --bg-card: #ffffff;
  --bg-card-border: rgba(0, 0, 0, 0.08);
  --text-primary: #1d1d1f;
  --text-secondary: #6e6e73;
  --text-tertiary: #86868b;
  --accent: #0071e3;
  --accent-hover: #0077ed;
  --accent-subtle: rgba(0, 113, 227, 0.08);
  --nav-bg: rgba(255, 255, 255, 0.85);
  --nav-border: rgba(0, 0, 0, 0.1);
  --hero-gradient: linear-gradient(180deg, #f5f5f7 0%, #ffffff 100%);
  --feature-bg: #f5f5f7;
  --shadow-card: 0 2px 20px rgba(0, 0, 0, 0.08);
  --shadow-btn: 0 4px 16px rgba(0, 113, 227, 0.3);
  --divider: rgba(0, 0, 0, 0.08);
  --step-num: rgba(0, 113, 227, 0.12);
  --privacy-bg: #f5f5f7;
}

[data-theme="dark"] {
  --bg: #000000;
  --bg-secondary: #111111;
  --bg-card: #1c1c1e;
  --bg-card-border: rgba(255, 255, 255, 0.08);
  --text-primary: #f5f5f7;
  --text-secondary: #a1a1a6;
  --text-tertiary: #6e6e73;
  --accent: #2997ff;
  --accent-hover: #40a9ff;
  --accent-subtle: rgba(41, 151, 255, 0.12);
  --nav-bg: rgba(0, 0, 0, 0.85);
  --nav-border: rgba(255, 255, 255, 0.1);
  --hero-gradient: linear-gradient(180deg, #111111 0%, #000000 100%);
  --feature-bg: #1c1c1e;
  --shadow-card: 0 2px 20px rgba(0, 0, 0, 0.4);
  --shadow-btn: 0 4px 16px rgba(41, 151, 255, 0.3);
  --divider: rgba(255, 255, 255, 0.08);
  --step-num: rgba(41, 151, 255, 0.12);
  --privacy-bg: #1c1c1e;
}

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

html { scroll-behavior: smooth; font-size: 16px; }

body {
  font-family: var(--font-body);
  background: var(--bg);
  color: var(--text-primary);
  line-height: 1.6;
  transition: background 0.3s ease, color 0.3s ease;
  overflow-x: hidden;
}

img { max-width: 100%; display: block; }
a { color: var(--accent); text-decoration: none; }
a:hover { color: var(--accent-hover); }

/* ── Nav ── */
nav {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  background: var(--nav-bg);
  border-bottom: 1px solid var(--nav-border);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  height: 52px;
  display: flex;
  align-items: center;
}

.nav-inner {
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.nav-logo {
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-primary);
  text-decoration: none;
  letter-spacing: -0.01em;
}

.nav-logo img {
  width: 28px;
  height: 28px;
  border-radius: 6px;
}

.nav-logo-icon {
  width: 28px;
  height: 28px;
  background: var(--accent);
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: white;
  font-size: 14px;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 28px;
  list-style: none;
}

.nav-links a {
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 400;
  transition: color 0.2s;
  text-decoration: none;
}

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

.nav-controls {
  display: flex;
  align-items: center;
  gap: 12px;
}

/* Language switcher */
.lang-switch {
  display: flex;
  align-items: center;
  background: var(--bg-secondary);
  border-radius: 20px;
  padding: 3px;
  gap: 2px;
  border: 1px solid var(--bg-card-border);
}

.lang-btn {
  background: none;
  border: none;
  cursor: pointer;
  font-size: 0.75rem;
  font-weight: 500;
  color: var(--text-tertiary);
  padding: 3px 10px;
  border-radius: 16px;
  transition: all 0.2s;
  font-family: var(--font-body);
  letter-spacing: 0.03em;
}

.lang-btn.active {
  background: var(--bg-card);
  color: var(--text-primary);
  box-shadow: 0 1px 4px rgba(0,0,0,0.1);
}

/* Theme toggle */
.theme-toggle {
  background: none;
  border: none;
  cursor: pointer;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-secondary);
  transition: background 0.2s, color 0.2s;
}

.theme-toggle:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.theme-toggle svg { width: 18px; height: 18px; }

.icon-sun { display: none; }
.icon-moon { display: block; }
[data-theme="dark"] .icon-sun { display: block; }
[data-theme="dark"] .icon-moon { display: none; }

/* ── Hero ── */
.hero {
  background: var(--hero-gradient);
  padding: 140px 24px 100px;
  text-align: center;
  position: relative;
  overflow: hidden;
}

.hero::before {
  content: '';
  position: absolute;
  top: -200px;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, var(--accent-subtle) 0%, transparent 70%);
  pointer-events: none;
}

.hero-app-icon {
  width: 120px;
  height: 120px;
  border-radius: 27px;
  margin: 0 auto 32px;
  background: var(--accent);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 52px;
  box-shadow: 0 20px 60px rgba(0, 113, 227, 0.3);
  animation: float 4s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0px); }
  50% { transform: translateY(-8px); }
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.4rem, 5vw, 4rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  line-height: 1.1;
  margin-bottom: 16px;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.25rem);
  color: var(--text-secondary);
  max-width: 480px;
  margin: 0 auto 40px;
  font-weight: 300;
  letter-spacing: -0.01em;
}

.hero-ctas {
  display: flex;
  gap: 12px;
  justify-content: center;
  flex-wrap: wrap;
}

.btn-primary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--accent);
  color: #fff;
  padding: 14px 28px;
  border-radius: 980px;
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  transition: all 0.2s;
  box-shadow: var(--shadow-btn);
  text-decoration: none;
}

.btn-primary:hover {
  background: var(--accent-hover);
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 6px 20px rgba(0, 113, 227, 0.4);
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  background: var(--bg-secondary);
  color: var(--text-primary);
  padding: 14px 28px;
  border-radius: 980px;
  font-size: 0.95rem;
  font-weight: 500;
  letter-spacing: -0.01em;
  transition: all 0.2s;
  border: 1px solid var(--bg-card-border);
  text-decoration: none;
}

.btn-secondary:hover {
  background: var(--feature-bg);
  color: var(--text-primary);
  transform: translateY(-1px);
}

/* ── Sections ── */
section {
  padding: 96px 24px;
}

.container {
  max-width: 1080px;
  margin: 0 auto;
}

.section-label {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--accent);
  margin-bottom: 12px;
}

.section-heading {
  font-family: var(--font-display);
  font-size: clamp(1.8rem, 3vw, 2.8rem);
  font-weight: 700;
  letter-spacing: -0.03em;
  color: var(--text-primary);
  line-height: 1.15;
  margin-bottom: 16px;
}

.section-body {
  font-size: 1.1rem;
  color: var(--text-secondary);
  max-width: 600px;
  line-height: 1.7;
  font-weight: 300;
}

/* ── Intro ── */
.intro {
  background: var(--bg);
  border-top: 1px solid var(--divider);
  border-bottom: 1px solid var(--divider);
}

.intro .container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 64px;
  align-items: center;
}

.intro-visual {
  display: flex;
  align-items: center;
  justify-content: center;
}

.phone-mockup {
  width: 200px;
  height: 400px;
  background: var(--bg-card);
  border-radius: 36px;
  border: 1px solid var(--bg-card-border);
  box-shadow: var(--shadow-card);
  display: flex;
  align-items: center;
  justify-content: center;
  position: relative;
  overflow: hidden;
}

.phone-mockup::before {
  content: '';
  position: absolute;
  top: 12px;
  left: 50%;
  transform: translateX(-50%);
  width: 60px;
  height: 6px;
  background: var(--bg-card-border);
  border-radius: 3px;
}

.phone-screen {
  padding: 32px 16px 16px;
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.mock-title {
  font-size: 0.7rem;
  font-weight: 700;
  color: var(--text-primary);
  padding: 0 4px;
}

.mock-reminder {
  background: var(--bg-secondary);
  border-radius: 10px;
  padding: 10px 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.mock-dot {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--accent);
  flex-shrink: 0;
}

.mock-text {
  font-size: 0.6rem;
  color: var(--text-primary);
  font-weight: 500;
}

.mock-sub {
  font-size: 0.55rem;
  color: var(--text-secondary);
}

/* ── Features ── */
.features {
  background: var(--bg-secondary);
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 20px;
  margin-top: 48px;
}

.feature-card {
  background: var(--bg-card);
  border: 1px solid var(--bg-card-border);
  border-radius: 20px;
  padding: 28px;
  transition: transform 0.2s, box-shadow 0.2s;
}

.feature-card:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-card);
}

.feature-icon {
  width: 48px;
  height: 48px;
  background: var(--accent-subtle);
  border-radius: 12px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
  font-size: 22px;
  color: var(--accent);
}

.feature-title {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.feature-desc {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ── How it works ── */
.how {
  background: var(--bg);
}

.how .container {
  display: grid;
  grid-template-columns: 1fr 2fr;
  gap: 64px;
  align-items: start;
}

.steps {
  display: flex;
  flex-direction: column;
  gap: 32px;
  margin-top: 0;
}

.step {
  display: flex;
  gap: 20px;
  align-items: flex-start;
}

.step-number {
  font-family: var(--font-display);
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--accent);
  background: var(--step-num);
  width: 40px;
  height: 40px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  letter-spacing: 0.05em;
}

.step-content h3 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 4px;
  letter-spacing: -0.01em;
}

.step-content p {
  font-size: 0.9rem;
  color: var(--text-secondary);
  line-height: 1.6;
}

/* ── Privacy Section ── */
.privacy-section {
  background: var(--privacy-bg);
  border-top: 1px solid var(--divider);
  border-bottom: 1px solid var(--divider);
  text-align: center;
}

.privacy-section .section-body {
  margin: 0 auto 24px;
}

.privacy-section .section-heading {
  margin-bottom: 16px;
}

/* ── Download ── */
.download {
  background: var(--bg);
  text-align: center;
}

.download .section-heading { margin-bottom: 12px; }
.download .section-body { margin: 0 auto 32px; }

/* ── Footer ── */
footer {
  background: var(--bg-secondary);
  border-top: 1px solid var(--divider);
  padding: 40px 24px;
  text-align: center;
}

.footer-inner {
  max-width: 1080px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 16px;
}

.footer-copy {
  font-size: 0.8rem;
  color: var(--text-tertiary);
}

.footer-links {
  display: flex;
  gap: 20px;
}

.footer-links a {
  font-size: 0.8rem;
  color: var(--text-tertiary);
  transition: color 0.2s;
  text-decoration: none;
}

.footer-links a:hover { color: var(--text-secondary); }

/* ── Animations ── */
.fade-in {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
  opacity: 1;
  transform: translateY(0);
}

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

  .intro .container,
  .how .container {
    grid-template-columns: 1fr;
    gap: 40px;
  }

  .intro-visual { order: -1; }

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

  .footer-inner {
    flex-direction: column;
    text-align: center;
  }

  .hero { padding: 120px 24px 80px; }
}

@media (max-width: 480px) {
  .features-grid { grid-template-columns: 1fr; }
  .hero-ctas { flex-direction: column; align-items: center; }
}