body {
  margin: 0;
  font-family: 'Segoe UI', sans-serif;
  background-color: #121212;
  color: #fff;
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  background-color: #1c1c1c;
  padding: 10px 20px;
  box-shadow: 0 2px 5px rgba(0,0,0,0.5);
  flex-wrap: wrap;
}

header img {
  width: 40px;
  height: 40px;
  margin-right: 10px;
}

.header-left {
  display: flex;
  align-items: center;
}

h1 {
  font-size: 1.5rem;
  color: #0ff;
}

.login-controls button {
  background-color: #222;
  border: none;
  color: white;
  padding: 8px 14px;
  margin: 5px;
  border-radius: 6px;
  cursor: pointer;
}

.login-controls button:hover {
  background-color: #00bcd4;
  color: black;
}

main {
  flex: 1;
  padding: 20px;
  text-align: center;
}

h2 {
  color: #0ff;
  margin-bottom: 20px;
}

/* TOOL GRID */
.tool-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 20px;
}

.tool-card {
  background-color: #1e1e1e;
  border: 1px solid #333;
  border-radius: 12px;
  padding: 20px;
  text-align: center;
  box-shadow: 0 4px 10px rgba(0,0,0,0.3);
}

.tool-card h3 {
  margin-bottom: 10px;
  color: #00bcd4;
}

.tool-btn {
  display: inline-block;
  margin-top: 10px;
  padding: 10px 16px;
  background-color: #00bcd4;
  color: #000;
  text-decoration: none;
  border-radius: 8px;
  font-weight: bold;
}

.tool-btn:hover {
  background-color: #008c9e;
  color: #fff;
}

/* CALCULATORS */
.calc-box {
  background-color: #1e1e1e;
  padding: 20px;
  border-radius: 12px;
  max-width: 400px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.calc-box input[type="number"], 
.calc-box input[type="text"] {
  padding: 10px;
  border-radius: 8px;
  border: none;
  outline: none;
  background-color: #2a2a2a;
  color: white;
}

.calc-box button {
  background-color: #00bcd4;
  color: black;
  border: none;
  padding: 10px;
  border-radius: 8px;
  font-weight: bold;
  cursor: pointer;
}

.calc-box button:hover {
  background-color: #008c9e;
  color: white;
}

#resultArea {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
}

#resultArea input {
  flex: 1;
}

/* FOOTER */
footer {
  text-align: center;
  padding: 15px;
  background-color: #1c1c1c;
  font-size: 0.9em;
  color: #aaa;
}

/* MOBILE FRIENDLY */
@media (max-width: 600px) {
  header {
    flex-direction: column;
    align-items: flex-start;
  }
  .tool-grid {
    grid-template-columns: 1fr;
  }
  #resultArea {
    flex-direction: column;
  }
}