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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: #e9ecef;
    background: linear-gradient(135deg, #1a1a2e 0%, #16213e 50%, #0f3460 100%);
    min-height: 100vh;
}

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

.header {
    text-align: center;
    color: #ffffff;
    margin-bottom: 30px;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    text-shadow: 2px 2px 8px rgba(0,0,0,0.5);
    background: linear-gradient(45deg, #64b5f6, #42a5f5);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.header p {
    font-size: 1.2rem;
    opacity: 0.9;
    color: #b0bec5;
}

.main-content {
    background: #1e1e1e;
    border-radius: 15px;
    padding: 30px;
    box-shadow: 0 10px 30px rgba(0,0,0,0.4);
    border: 1px solid #333;
}

.code-section {
    background: #2d2d2d;
    border: 1px solid #444;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    font-family: 'Courier New', monospace;
    overflow-x: auto;
    color: #f8f8f2;
}

.hint-section {
    margin-bottom: 40px;
}

.hint-section h2 {
    color: #64b5f6;
    border-bottom: 3px solid #42a5f5;
    padding-bottom: 10px;
    margin-bottom: 20px;
    font-size: 1.8rem;
}

.hint-card {
    background: #2a2a2a;
    border-left: 4px solid #42a5f5;
    padding: 20px;
    margin-bottom: 20px;
    border-radius: 0 8px 8px 0;
    box-shadow: 0 2px 5px rgba(0,0,0,0.3);
    border: 1px solid #3a3a3a;
}

.hint-card h3 {
    color: #64b5f6;
    margin-bottom: 10px;
    font-size: 1.3rem;
}

.warning {
    border-left-color: #f44336;
    background: #3d1a1a;
}

.warning h3 {
    color: #ff6b6b;
}

.best-practice {
    border-left-color: #4caf50;
    background: #1a3d1a;
}

.best-practice h3 {
    color: #66bb6a;
}

.info {
    border-left-color: #ff9800;
    background: #3d2f1a;
}

.info h3 {
    color: #ffb74d;
}

.code-highlight {
    background: #3a3a3a;
    color: #64b5f6;
    padding: 2px 6px;
    border-radius: 4px;
    font-family: 'Courier New', monospace;
    font-size: 0.9em;
    border: 1px solid #555;
}

.improvements {
    background: #1a3d1a;
    border: 1px solid #4caf50;
    border-radius: 8px;
    padding: 20px;
    margin-top: 30px;
}

.improvements h2 {
    color: #66bb6a;
    border-bottom: 2px solid #4caf50;
    margin-bottom: 15px;
}

.improvement-item {
    margin-bottom: 15px;
    padding: 10px;
    background: #2a2a2a;
    border-radius: 5px;
    border: 1px solid #3a3a3a;
}

.redacted {
    background: #3a3a3a;
    color: transparent;
    padding: 2px 8px;
    border-radius: 4px;
    border: 2px dashed #64b5f6;
    font-family: 'Courier New', monospace;
    display: inline-block;
    min-width: 60px;
    text-align: center;
}

.quiz-instructions {
    background: #3d2f1a;
    border: 1px solid #ff9800;
    border-radius: 8px;
    padding: 20px;
    margin-bottom: 30px;
    text-align: center;
}

.quiz-instructions h3 {
    color: #ffb74d;
    margin-bottom: 10px;
}

.quiz-note {
    background: #2a2a2a;
    border: 1px solid #555;
    border-radius: 5px;
    padding: 10px;
    margin-top: 15px;
    font-style: italic;
    color: #b0bec5;
}

/* Custom Scrollbar */
::-webkit-scrollbar {
    width: 12px;
}

::-webkit-scrollbar-track {
    background: #1a1a1a;
    border-radius: 10px;
}

::-webkit-scrollbar-thumb {
    background: linear-gradient(135deg, #42a5f5, #64b5f6);
    border-radius: 10px;
    border: 2px solid #1a1a1a;
}

::-webkit-scrollbar-thumb:hover {
    background: linear-gradient(135deg, #1e88e5, #42a5f5);
    transform: scale(1.1);
}

::-webkit-scrollbar-thumb:active {
    background: linear-gradient(135deg, #1565c0, #1e88e5);
}

::-webkit-scrollbar-corner {
    background: #1a1a1a;
}

/* Firefox scrollbar */
html {
    scrollbar-width: thin;
    scrollbar-color: #42a5f5 #1a1a1a;
}