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

:root {
  --black: #0d0d0d;
  --dark: #1a1a1a;
  --red: #c41e3a;
  --brown: #5c4033;
  --green: #2e7d32;
  --white: #f5f5f5;
  --light: #e0e0e0;
}

body {
  font-family: 'Segoe UI', system-ui, -apple-system, sans-serif;
  background: var(--black);
  color: var(--white);
  min-height: 100vh;
  line-height: 1.5;
}

/* Header */
header {
  background: var(--dark);
  border-bottom: 2px solid var(--red);
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: 500px;
  margin: 0 auto;
  padding: 14px 18px;
  display: flex;
  align-items: center;
  gap: 15px;
}

.hamburger {
  display: flex;
  flex-direction: column;
  gap: 5px;
  cursor: pointer;
}

.hamburger span {
  width: 24px;
  height: 2.5px;
  background: var(--white);
  border-radius: 2px;
}

.logo-text {
  font-weight: 700;
  font-size: 1.3rem;
  color: var(--red);
  letter-spacing: 1px;
}

/* Side Menu */
.side-menu {
  position: fixed;
  top: 0;
  left: -280px;
  width: 280px;
  height: 100%;
  background: var(--dark);
  z-index: 200;
  transition: left 0.3s ease;
  border-right: 2px solid var(--red);
  overflow-y: auto;
}

.side-menu.open {
  left: 0;
}

.side-menu-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 18px 20px;
  border-bottom: 1px solid #333;
  font-weight: 600;
}

.close-btn {
  background: none;
  border: none;
  color: var(--white);
  font-size: 1.4rem;
  cursor: pointer;
}

.side-menu ul {
  list-style: none;
  padding: 15px 0;
}

.side-menu li a {
  display: block;
  padding: 14px 22px;
  color: var(--light);
  text-decoration: none;
  font-size: 1rem;
  transition: background 0.2s;
}

.side-menu li a:hover {
  background: rgba(196, 30, 58, 0.15);
  color: var(--red);
}

.overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.55);
  z-index: 150;
  opacity: 0;
  visibility: hidden;
  transition: 0.3s;
}

.overlay.show {
  opacity: 1;
  visibility: visible;
}

/* Container */
.container {
  max-width: 500px;
  margin: 0 auto;
  padding: 30px 18px 40px;
}

.page {
  display: none;
  animation: fadeIn 0.3s ease;
}

.page.active {
  display: block;
}

@keyframes fadeIn {
  from { opacity: 0; transform: translateY(10px); }
  to { opacity: 1; transform: translateY(0); }
}

.welcome {
  font-size: 1.45rem;
  text-align: center;
  line-height: 1.35;
  margin-bottom: 8px;
}

.reg-no {
  text-align: center;
  color: var(--red);
  font-weight: 600;
  font-size: 0.95rem;
  margin-bottom: 6px;
}

.subtitle {
  text-align: center;
  color: var(--light);
  margin-bottom: 28px;
  font-size: 0.95rem;
}

h2 {
  text-align: center;
  margin-bottom: 20px;
  font-size: 1.35rem;
}

/* Buttons */
.btn-group {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.btn {
  display: block;
  width: 100%;
  padding: 14px 16px;
  border: none;
  border-radius: 10px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  transition: all 0.25s ease;
  color: white;
}

.btn:hover {
  transform: translateY(-2px);
  opacity: 0.93;
}

.btn-merah { background: var(--red); }
.btn-hitam { background: #2a2a2a; border: 1px solid #444; }
.btn-coklat { background: var(--brown); }
.btn-putih { background: var(--white); color: var(--black); }
.btn-hijau { background: var(--green); }

/* Form elements */
input {
  width: 100%;
  padding: 14px;
  margin-bottom: 14px;
  border-radius: 10px;
  border: 1px solid #444;
  background: #111;
  color: var(--white);
  font-size: 1rem;
}

input::placeholder {
  color: #888;
}

.result, .info-box {
  background: #111;
  border: 1px solid #333;
  border-radius: 10px;
  padding: 18px;
  margin: 18px 0;
  font-size: 0.95rem;
  line-height: 1.6;
  color: var(--light);
  text-align: center;
}

/* Footer */
footer {
  text-align: center;
  padding: 22px 15px;
  background: var(--dark);
  border-top: 1px solid #333;
  color: #888;
  font-size: 0.85rem;
}

@media (max-width: 480px) {
  .welcome {
    font-size: 1.25rem;
  }
}

.pilih-jenis {
  display: flex;
  gap: 10px;
  margin-bottom: 14px;
}

.jenis-btn {
  flex: 1;
  padding: 11px;
  border: 1px solid #444;
  background: #222;
  color: var(--light);
  border-radius: 8px;
  font-size: 0.95rem;
  font-weight: 600;
  cursor: pointer;
  transition: all 0.2s;
}

.jenis-btn.active {
  background: var(--red);
  border-color: var(--red);
  color: white;
}