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

:root {
  --primary: #2563eb;
  --primary-hover: #1d4ed8;
  --background: #ffffff;
  --text: #1f2937;
  --text-light: #6b7280;
  --border: #e5e7eb;
  --error: #dc2626;
  --overlay: rgba(0, 0, 0, 0.5);
}

html {
  /* Base font size = 62.5% or 10px for easy rem usage */
  font-size: 62.5%;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  color: var(--text);
  font-size: 1.6rem;
  background: var(--background);
  line-height: 1.6;
}

.container {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* Header */
.header {
  background: var(--background);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 6rem;
}

.logo {
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
}

/* Desktop Navigation */
.nav-desktop {
  display: flex;
  align-items: center;
  gap: 2rem;
}

.nav-desktop a {
  color: var(--text);
  text-decoration: none;
  font-size: 1.5rem;
  transition: color 0.2s;
}

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

.btn-login {
  background: var(--primary);
  color: white;
  border: none;
  padding: 0.5rem 1.5rem;
  border-radius: 0.5rem;
  cursor: pointer;
  font-size: 1.4rem;
  transition: background 0.2s;
}

.btn-login:hover {
  background: var(--primary-hover);
}

/* Burger Menu */
.burger-menu {
  display: none;
  flex-direction: column;
  gap: 0.35rem;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.burger-menu span {
  width: 1.5rem;
  height: 2px;
  background: var(--text);
  transition: transform 0.3s, opacity 0.3s;
}

.burger-menu.active span:nth-child(1) {
  transform: translateY(0.55rem) rotate(45deg);
}

.burger-menu.active span:nth-child(2) {
  opacity: 0;
}

.burger-menu.active span:nth-child(3) {
  transform: translateY(-0.55rem) rotate(-45deg);
}

/* Mobile Navigation */
.nav-mobile {
  display: none;
  flex-direction: column;
  gap: 0.5rem;
  padding: 1rem 0;
  border-top: 1px solid var(--border);
}

.nav-mobile.active {
  display: flex;
}

.nav-mobile a {
  color: var(--text);
  text-decoration: none;
  padding: 0.75rem 0;
  transition: color 0.2s;
}

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

.btn-login-mobile {
  background: var(--primary);
  color: white;
  border: none;
  padding: 0.75rem;
  border-radius: 0.5rem;
  cursor: pointer;
  margin-top: 0.5rem;
  transition: background 0.2s;
}

.btn-login-mobile:hover {
  background: var(--primary-hover);
}

/* Hero Section */
.hero {
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: calc(100vh - 4rem);
  padding: 3rem 0;
}

.hero-content {
  text-align: center;
  max-width: 800px;
}

.hero-title {
  font-size: 3.5rem;
  font-weight: 700;
  margin-bottom: 2rem;
  color: var(--text);
}

.hero-quote {
  font-size: 1.5rem;
  line-height: 1.6;
  color: var(--text-light);
  font-style: italic;
  margin-bottom: 1rem;
  min-height: 4.5rem;
}

.hero-author {
  font-size: 1.125rem;
  color: var(--primary);
  font-weight: 500;
}

.about-title {
  margin-top: 4rem;
  margin-bottom: 2rem;
}

.about-content {
  display: flex;
  font-size: 2rem;
}

.about-img {
  margin-left: 1rem;
}

.about-img img {
  max-width: 15rem;
  border: 3px solid var(--text);
  border-radius: 1rem;
}

.history {
  margin-top: 4rem;
  font-size: 2rem;
}

.history h2 {
  font-size: 3rem;
  margin-bottom: 1rem;
}

.history h3 {
  margin-top: 1.5rem;
}

.history ul {
  margin-left: 2rem;
}

/* Login Dialog */
.dialog-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: var(--overlay);
  z-index: 1000;
  align-items: center;
  justify-content: center;
  padding: 1rem;
}

.dialog-overlay.active {
  display: flex;
}

.dialog {
  background: var(--background);
  border-radius: 0.75rem;
  padding: 2rem;
  max-width: 400px;
  width: 100%;
  position: relative;
  box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
}

.dialog-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  background: none;
  border: none;
  font-size: 2rem;
  line-height: 1;
  cursor: pointer;
  color: var(--text-light);
  transition: color 0.2s;
}

.dialog-close:hover {
  color: var(--text);
}

.dialog-title {
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  color: var(--text);
}

.login-form {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

.form-group label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text);
}

.form-group input {
  padding: 0.75rem;
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  font-size: 1rem;
  transition: border-color 0.2s;
}

.form-group input:focus {
  outline: none;
  border-color: var(--primary);
}

.form-error {
  color: var(--error);
  font-size: 0.875rem;
  min-height: 1.25rem;
}

.btn-submit {
  background: var(--primary);
  color: white;
  border: none;
  padding: 0.75rem;
  border-radius: 0.5rem;
  font-size: 1rem;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s;
}

.btn-submit:hover {
  background: var(--primary-hover);
}

.btn-submit:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

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

  .burger-menu {
    display: flex;
  }

  .hero-title {
    font-size: 2.5rem;
  }

  .hero-quote {
    font-size: 1.25rem;
  }

  .hero-author {
    font-size: 1rem;
  }
}