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

:root {
	--bg-primary: #1D8497;
	--bg-secondary: #156b7a;
	--text-primary: #ffffff;
	--text-secondary: #e0e0e0;
	--accent: #00ff41;
	--button-bg: #2a2a2a;
	--button-hover: #3a3a3a;
	--border: #444;
	--card-bg: rgba(255, 255, 255, 0.1);
	--modal-bg: rgba(0, 0, 0, 0.8);
}

body {
	font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
	background: var(--bg-primary);
	color: var(--text-primary);
	line-height: 1.6;
	min-height: 100vh;
}

.container {
	max-width: 1200px;
	margin: 0 auto;
	padding: 0 20px;
}


.navbar {
	background: var(--bg-secondary);
	padding: 1rem 0;
	box-shadow: 0 2px 10px rgba(0, 0, 0, 0.3);
	position: sticky;
	top: 0;
	z-index: 100;
}

.nav-content {
	display: flex;
	justify-content: space-between;
	align-items: center;
}

.logo {
	font-size: 1.5rem;
	font-weight: bold;
	color: var(--accent);
	cursor: pointer;
}

.nav-links {
	display: flex;
	list-style: none;
	gap: 2rem;
}

.nav-links a {
	color: var(--text-primary);
	text-decoration: none;
	transition: color 0.3s;
	padding: 0.5rem 1rem;
	border-radius: 5px;
}

.nav-links a:hover,
.nav-links a.active {
	color: var(--accent);
	background: rgba(0, 255, 65, 0.1);
}

.nav-actions {
	display: flex;
	gap: 1rem;
	align-items: center;
}

/* Buttons */
.btn {
	padding: 0.5rem 1rem;
	border: none;
	border-radius: 5px;
	cursor: pointer;
	font-size: 0.9rem;
	transition: all 0.3s;
	text-decoration: none;
	display: inline-block;
	text-align: center;
}

.btn-primary {
	background: var(--accent);
	color: #000;
}

.btn-primary:hover {
	background: #00cc33;
	transform: translateY(-2px);
}

.btn-secondary {
	background: var(--button-bg);
	color: var(--text-primary);
	border: 1px solid var(--border);
}

.btn-secondary:hover {
	background: var(--button-hover);
}

/* Sections */
.section {
	display: none;
	padding: 2rem 0;
	min-height: calc(100vh - 80px);
}

.section.active {
	display: block;
}

/* Home Section */
.hero {
	text-align: center;
	padding: 4rem 0;
}

.hero h1 {
	font-size: 3rem;
	margin-bottom: 1rem;
	color: var(--accent);
}

.hero p {
	font-size: 1.2rem;
	margin-bottom: 2rem;
	max-width: 600px;
	margin-left: auto;
	margin-right: auto;
}

.features {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
	gap: 2rem;
	margin-top: 4rem;
}

.feature-card {
	background: var(--card-bg);
	padding: 2rem;
	border-radius: 10px;
	text-align: center;
	backdrop-filter: blur(10px);
	border: 1px solid rgba(255, 255, 255, 0.1);
}

/* Calculator Section */
.calculator-container {
	display: flex;
	justify-content: center;
	align-items: center;
	min-height: 80vh;
	padding: 2rem 0;
}

.calculator {
	background: #2a2a2a;
	border-radius: 15px;
	padding: 20px;
	box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
	max-width: 400px;
	width: 100%;
}

.calculator-header {
	text-align: center;
	margin-bottom: 20px;
}

.model-selector-btn {
	background: var(--accent);
	color: #000;
	border: none;
	padding: 0.5rem 1rem;
	border-radius: 5px;
	cursor: pointer;
	font-weight: bold;
	margin-bottom: 10px;
}

.calculator-display {
	background: #1a4a3a;
	color: var(--accent);
	padding: 15px;
	border-radius: 8px;
	margin-bottom: 20px;
	font-family: 'Courier New', monospace;
	min-height: 120px;
	border: 2px solid #0a3a2a;
}

.display-main {
	font-size: 1.5rem;
	text-align: right;
	margin-bottom: 10px;
	min-height: 30px;
}

.display-history {
	font-size: 0.8rem;
	opacity: 0.7;
	max-height: 60px;
	overflow-y: auto;
}

.calculator-modes {
	display: flex;
	gap: 5px;
	margin-bottom: 15px;
}

.mode-btn {
	flex: 1;
	padding: 8px;
	background: var(--button-bg);
	color: var(--text-primary);
	border: 1px solid var(--border);
	border-radius: 5px;
	cursor: pointer;
	font-size: 0.8rem;
}

.mode-btn.active {
	background: var(--accent);
	color: #000;
}

/* FIXED: Calculator Buttons Grid */
.calculator-buttons {
	display: grid;
	grid-template-columns: repeat(5, 1fr);
	gap: 8px;
	width: 100%;
}

.calc-btn {
	padding: 12px 6px;
	background: var(--button-bg);
	color: var(--text-primary);
	border: 1px solid var(--border);
	border-radius: 5px;
	cursor: pointer;
	font-size: 0.75rem;
	transition: all 0.2s;
	min-height: 45px;
	display: flex;
	align-items: center;
	justify-content: center;
	text-align: center;
	word-break: break-word;
}

.calc-btn:hover {
	background: var(--button-hover);
	transform: translateY(-1px);
}

.calc-btn:active {
	transform: translateY(0);
}

.calc-btn.operator {
	background: #4a4a4a;
}

.calc-btn.function {
	background: #3a5a3a;
	font-size: 0.7rem;
}

.calc-btn.wide {
	grid-column: span 2;
}

/* Graph Canvas */
.graph-container {
	margin-top: 20px;
	text-align: center;
}

.graph-canvas {
	border: 2px solid var(--border);
	border-radius: 8px;
	background: #1a1a1a;
}

.graph-controls {
	margin-top: 10px;
	display: flex;
	gap: 10px;
	flex-wrap: wrap;
	justify-content: center;
}

.graph-input {
	padding: 5px;
	border: 1px solid var(--border);
	border-radius: 3px;
	background: var(--button-bg);
	color: var(--text-primary);
	font-size: 0.8rem;
}

/* Matrix Display */
.matrix-container {
	margin-top: 20px;
}

.matrix-display {
	background: var(--button-bg);
	padding: 15px;
	border-radius: 8px;
	font-family: 'Courier New', monospace;
	font-size: 0.9rem;
	max-height: 200px;
	overflow-y: auto;
}

.matrix-controls {
	margin-top: 10px;
	display: flex;
	gap: 10px;
	flex-wrap: wrap;
}

/* Modal Styles */
.modal {
	display: none;
	position: fixed;
	top: 0;
	left: 0;
	width: 100%;
	height: 100%;
	background: var(--modal-bg);
	z-index: 1000;
	backdrop-filter: blur(5px);
}

.modal.active {
	display: flex;
	align-items: center;
	justify-content: center;
}

.modal-content {
	background: var(--bg-secondary);
	padding: 2rem;
	border-radius: 15px;
	max-width: 600px;
	width: 90%;
	max-height: 80vh;
	overflow-y: auto;
	position: relative;
}

.modal-close {
	position: absolute;
	top: 15px;
	right: 20px;
	background: none;
	border: none;
	font-size: 1.5rem;
	color: var(--text-primary);
	cursor: pointer;
}

.model-grid {
	display: grid;
	grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
	gap: 1.5rem;
	margin-top: 1rem;
}

.model-card {
	background: var(--card-bg);
	padding: 1.5rem;
	border-radius: 10px;
	text-align: center;
	cursor: pointer;
	transition: all 0.3s;
	border: 2px solid transparent;
}

.model-card:hover {
	transform: translateY(-5px);
	border-color: var(--accent);
	box-shadow: 0 10px 25px rgba(0, 255, 65, 0.2);
}

.model-card h3 {
	color: var(--accent);
	margin-bottom: 0.5rem;
}

/* Auth Form */
.auth-form {
	display: flex;
	flex-direction: column;
	gap: 1rem;
}

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

.form-input {
	padding: 0.75rem;
	border: 1px solid var(--border);
	border-radius: 5px;
	background: var(--button-bg);
	color: var(--text-primary);
	font-size: 1rem;
}

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

/* ==================== MOBILE OPTIMIZATION ==================== */

/* Mobile Mode Switcher */
.mobile-mode-switcher {
  display: none;
  text-align: center;
  margin: 10px 0;
  gap: 10px;
}

.mode-switch-btn {
  padding: 8px 16px;
  background: var(--button-bg);
  color: var(--text-primary);
  border: 1px solid var(--border);
  border-radius: 5px;
  cursor: pointer;
  font-size: 0.8rem;
}

.mode-switch-btn.active {
  background: var(--accent);
  color: #000;
}

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

	.hero h1 {
		font-size: 2rem;
	}

	.calculator {
		margin: 0 10px;
		padding: 15px;
	}

	/* KEEP 5 COLUMNS FOR CALCULATOR BUTTONS */
	.calculator-buttons {
		grid-template-columns: repeat(5, 1fr);
		gap: 6px;
	}

	.calc-btn {
		padding: 10px 4px;
		font-size: 0.65rem;
		min-height: 40px;
	}
  
  /* Mobile-specific enhancements */
  .mobile-mode-switcher {
    display: flex;
    justify-content: center;
  }
  
  /* Make calculator full width on mobile */
  .calculator {
    max-width: 100%;
    margin: 0;
    padding: 15px 10px;
  }
  
  /* Enhanced mobile button sizing */
  .calculator-buttons {
    grid-template-columns: repeat(5, 1fr);
    gap: 4px;
  }
  
  .calc-btn {
    min-height: 44px !important; /* Minimum touch target size */
    padding: 10px 2px;
    font-size: 0.7rem;
    touch-action: manipulation; /* Improves touch responsiveness */
  }
  
  /* Larger display for mobile */
  .calculator-display {
    min-height: 100px;
    padding: 12px;
  }
  
  .display-main {
    font-size: 1.8rem;
  }
  
  /* Stack graph controls vertically on mobile */
  .graph-controls {
    flex-direction: column;
    align-items: center;
  }
  
  .graph-input {
    width: 100% !important;
    max-width: 250px;
  }
  
  /* Adjust graph canvas for mobile */
  .graph-canvas {
    width: 100%;
    max-width: 100%;
    height: auto;
  }
  
  /* NEW: Larger touch targets */
  .calc-btn {
    min-height: 54px !important;
    padding: 12px 6px !important;
    font-size: 1rem !important;
  }
  
  /* NEW: Mobile navigation */
  .nav-links {
    display: none;
  }
  
  .mobile-menu-btn {
    display: block;
  }
  
  /* NEW: Better text sizing */
  .calculator-display {
    font-size: 1.5rem;
  }
}

/* Extra small devices */
@media (max-width: 480px) {
	.calculator-buttons {
		grid-template-columns: repeat(5, 1fr);
		gap: 4px;
	}
	
	.calc-btn {
		padding: 8px 2px;
		font-size: 0.6rem;
		min-height: 35px;
	}
  
  /* Mobile-specific enhancements for extra small devices */
  .calculator-buttons {
    grid-template-columns: repeat(5, 1fr);
    gap: 3px;
  }
  
  .calc-btn {
    min-height: 42px !important;
    padding: 8px 1px;
    font-size: 0.65rem;
  }
  
  /* Reduce padding on very small screens */
  .calculator {
    padding: 10px 5px;
  }
}

/* Landscape orientation optimization */
@media (max-width: 768px) and (orientation: landscape) {
  .calculator {
    max-width: 90%;
    margin: 0 auto;
  }
  
  .calculator-buttons {
    gap: 3px;
  }
  
  .calc-btn {
    min-height: 38px !important;
    padding: 6px 1px;
    font-size: 0.6rem;
  }
}

/* Prevent zoom on input for iOS */
@media (max-width: 768px) {
  .graph-input, .calc-btn {
    font-size: 16px; /* Prevents iOS zoom */
  }
}

/* Utility Classes */
.hidden {
	display: none !important;
}

.text-center {
	text-align: center;
}

.mt-2 {
	margin-top: 1rem;
}

.mb-2 {
	margin-bottom: 1rem;
}