:root {
  --bg-color: #020617;
  --card-bg: rgba(255, 255, 255, 0.03);
  --text-main: #f8fafc;
  --text-sub: #94a3b8;
  --accent: linear-gradient(135deg, #3b82f6, #8b5cf6);
  --input-bg: rgba(255, 255, 255, 0.05);
  --border: rgba(255, 255, 255, 0.1);
  --shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
}

.light-theme {
  --bg-color: #f1f5f9;
  --card-bg: #ffffff;
  --text-main: #1e293b;
  --text-sub: #64748b;
  --input-bg: #f8fafc;
  --border: #e2e8f0;
  --shadow: 0 10px 30px rgba(0, 0, 0, 0.05);
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: 'Inter', 'Segoe UI', sans-serif;
  transition: background 0.3s, color 0.3s;
}

body {
  min-height: 100vh;
  background-color: var(--bg-color);
  color: var(--text-main);
  padding: 20px;
  display: flex;
  flex-direction: column;
  align-items: center;
}

.navbar {
  width: 100%;
  max-width: 1000px;
  display: flex;
  justify-content: flex-end;
  padding: 20px 0;
}

.theme-toggle {
  cursor: pointer;
  padding: 10px;
  border-radius: 50%;
  background: var(--input-bg);
  border: 1px solid var(--border);
  width: 45px;
  height: 45px;
  display: flex;
  justify-content: center;
  align-items: center;
}

.container {
  max-width: 900px;
  width: 100%;
  margin-top: 20px;
}

header {
  text-align: center;
  margin-bottom: 40px;
}

h1 {
  font-size: 3.5rem;
  font-weight: 800;
  letter-spacing: -1px;
}

h1 span {
  background: var(--accent);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.subtitle {
  color: var(--text-sub);
  margin-top: 10px;
  font-size: 1.1rem;
}

.card {
  background: var(--card-bg);
  backdrop-filter: blur(12px);
  border: 1px solid var(--border);
  border-radius: 24px;
  padding: 30px;
  box-shadow: var(--shadow);
}

.form-group {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
}

.input-wrapper {
  flex: 2;
  position: relative;
  min-width: 250px;
}

.input-wrapper i {
  position: absolute;
  left: 15px;
  top: 50%;
  transform: translateY(-50%);
  color: var(--text-sub);
}

input {
  width: 100%;
  padding: 16px 16px 16px 45px;
  border-radius: 12px;
  border: 1px solid var(--border);
  background: var(--input-bg);
  color: var(--text-main);
  outline: none;
  font-size: 1rem;
}

/* Custom Select Styling */
.custom-select {
  position: relative;
  flex: 1;
  min-width: 160px;
  user-select: none;
}

.select-trigger {
  width: 100%;
  padding: 16px 20px;
  background: var(--input-bg);
  border: 1px solid var(--border);
  border-radius: 12px;
  cursor: pointer;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-main);
  transition: all 0.3s ease;
}

.select-options {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  right: 0;
  background: var(--bg-color);
  border: 1px solid var(--border);
  border-radius: 12px;
  overflow: hidden;
  display: none;
  z-index: 100;
  box-shadow: var(--shadow);
  backdrop-filter: blur(20px);
}

.custom-select.active .select-options {
  display: block;
}

.option {
  padding: 12px 20px;
  cursor: pointer;
  color: var(--text-sub);
}

.option:hover {
  background: var(--accent);
  color: white;
}

.option.selected {
  color: #3b82f6;
  background: rgba(59, 130, 246, 0.1);
}

.btn-primary {
  flex: 1;
  min-width: 150px;
  background: var(--accent);
  color: white;
  border: none;
  border-radius: 12px;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 10px;
}

.btn-primary:hover {
  filter: brightness(1.1);
  transform: translateY(-2px);
  box-shadow: 0 10px 20px rgba(59, 130, 246, 0.3);
}

#result-container {
  margin-top: 25px;
  background: var(--input-bg);
  padding: 15px 20px;
  border-radius: 12px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  border: 1px dashed var(--text-sub);
}

.btn-icon {
  background: none;
  border: none;
  color: var(--text-main);
  cursor: pointer;
  font-size: 1.2rem;
  padding: 5px;
}

.hidden { display: none !important; }

.features {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
  margin-top: 50px;
}

.feature-box {
  background: var(--card-bg);
  padding: 30px;
  border-radius: 20px;
  border: 1px solid var(--border);
  text-align: center;
  transition: transform 0.3s ease, border-color 0.3s ease;
}

.feature-box:hover {
  transform: translateY(-10px);
  border-color: #3b82f6;
}

.icon-circle {
  width: 60px;
  height: 60px;
  background: var(--accent);
  border-radius: 18px;
  display: flex;
  justify-content: center;
  align-items: center;
  margin: 0 auto 20px;
  color: white;
  font-size: 1.5rem;
}

.feature-box h3 {
  margin-bottom: 12px;
  font-size: 1.25rem;
}

.feature-box p {
  color: var(--text-sub);
  line-height: 1.6;
  font-size: 0.95rem;
}

footer {
  margin: 50px 0;
  text-align: center;
  color: var(--text-sub);
  font-size: 0.9rem;
}

@media (max-width: 768px) {
  h1 { font-size: 2.5rem; }
  .form-group { flex-direction: column; }
  .btn-primary, .custom-select { width: 100%; }
}