:root {
    --primary-color: #4361ee;
    --secondary-color: #3f37c9;
    --accent-color: #4895ef;
    --light-color: #f8f9fa;
    --dark-color: #212529;
    --success-color: #4bb543;
    --warning-color: #f0ad4e;
    --danger-color: #d9534f;
    --border-radius: 8px;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.1);
    --transition: all 0.3s ease;
}

.dark-mode {
    --primary-color: #4895ef;
    --secondary-color: #4361ee;
    --accent-color: #3f37c9;
    --light-color: #212529;
    --dark-color: #f8f9fa;
    --box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
}

body {
    background-color: var(--light-color);
    color: var(--dark-color);
    transition: var(--transition);
    line-height: 1.6;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

h1 {
    color: var(--primary-color);
    font-size: 2.5rem;
}

.theme-toggle {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.switch {
    position: relative;
    display: inline-block;
    width: 60px;
    height: 34px;
}

.switch input {
    opacity: 0;
    width: 0;
    height: 0;
}

.slider {
    position: absolute;
    cursor: pointer;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background-color: #ccc;
    transition: var(--transition);
}

.slider:before {
    position: absolute;
    content: "";
    height: 26px;
    width: 26px;
    left: 4px;
    bottom: 4px;
    background-color: white;
    transition: var(--transition);
}

input:checked + .slider {
    background-color: var(--primary-color);
}

input:checked + .slider:before {
    transform: translateX(26px);
}

.slider.round {
    border-radius: 34px;
}

.slider.round:before {
    border-radius: 50%;
}

.controls {
    background-color: rgba(67, 97, 238, 0.1);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin-bottom: 2rem;
    box-shadow: var(--box-shadow);
}

.shift-control {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.shift-control label {
    font-weight: 600;
}

.shift-control input[type="range"] {
    flex-grow: 1;
    height: 8px;
    border-radius: 4px;
    background: #ddd;
    outline: none;
    -webkit-appearance: none;
}

.shift-control input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background: var(--primary-color);
    cursor: pointer;
}

#shift-value {
    font-weight: bold;
    width: 30px;
    text-align: center;
}

.action-buttons {
    display: flex;
    gap: 1rem;
    flex-wrap: wrap;
}

button {
    padding: 0.75rem 1.5rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 600;
    display: flex;
    align-items: center;
    gap: 0.5rem;
    transition: var(--transition);
}

button.primary {
    background-color: var(--primary-color);
    color: white;
}

button.secondary {
    background-color: var(--secondary-color);
    color: white;
}

button:hover {
    transform: translateY(-2px);
    box-shadow: var(--box-shadow);
}

#analyze {
    background-color: var(--warning-color);
    color: var(--dark-color);
}

#sample {
    background-color: var(--accent-color);
    color: white;
}

#clear {
    background-color: var(--danger-color);
    color: white;
}

#animate-shift {
    background-color: #6c757d;
    color: white;
}

.text-areas {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
}

.text-box {
    position: relative;
}

label {
    display: block;
    margin-bottom: 0.5rem;
    font-weight: 600;
    color: var(--primary-color);
}

textarea {
    width: 100%;
    min-height: 200px;
    padding: 1rem;
    border: 2px solid #ddd;
    border-radius: var(--border-radius);
    resize: vertical;
    font-size: 1rem;
    transition: var(--transition);
    background-color: rgba(255, 255, 255, 0.8);
    color: var(--dark-color);
}

.dark-mode textarea {
    background-color: rgba(0, 0, 0, 0.2);
    border-color: #444;
}

textarea:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(67, 97, 238, 0.2);
}

.char-count {
    position: absolute;
    bottom: 40px;
    right: 10px;
    font-size: 0.8rem;
    color: #6c757d;
}

.copy-btn {
    position: absolute;
    bottom: 10px;
    right: 10px;
    padding: 0.5rem 1rem;
    background-color: var(--success-color);
    color: white;
}

.close-btn {
    position: absolute;
    top: 10px;
    right: 10px;
    padding: 0.5rem 1rem;
    background-color: var(--danger-color);
    color: white;
}

.frequency-analysis {
    background-color: rgba(67, 97, 238, 0.1);
    padding: 1.5rem;
    border-radius: var(--border-radius);
    box-shadow: var(--box-shadow);
}

.frequency-analysis h3 {
    margin-bottom: 1rem;
    color: var(--primary-color);
}

.frequency-chart {
    display: flex;
    height: 200px;
    align-items: flex-end;
    gap: 2px;
    margin-bottom: 1rem;
}

.bar {
    flex: 1;
    background-color: var(--accent-color);
    position: relative;
    transition: height 0.5s ease;
}

.bar-label {
    position: absolute;
    bottom: -20px;
    width: 100%;
    text-align: center;
    font-size: 0.8rem;
}

.suggestions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.5rem;
}

.suggestion {
    background-color: var(--warning-color);
    padding: 0.5rem 1rem;
    border-radius: var(--border-radius);
    font-size: 0.9rem;
    cursor: pointer;
}

.alphabet-animation {
    position: fixed;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    background-color: var(--light-color);
    padding: 2rem;
    border-radius: var(--border-radius);
    box-shadow: 0 0 20px rgba(0, 0, 0, 0.2);
    z-index: 1000;
    width: 80%;
    max-width: 800px;
    border: 2px solid var(--primary-color);
}

.alphabet-line {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-bottom: 1rem;
}

.letter {
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    font-weight: bold;
}

.original .letter {
    background-color: var(--primary-color);
    color: white;
}

.shifted .letter {
    background-color: var(--accent-color);
    color: white;
}

.hidden {
    display: none;
}

@media (max-width: 768px) {
    .text-areas {
        grid-template-columns: 1fr;
    }
    
    .action-buttons {
        flex-direction: column;
    }
    
    .shift-control {
        flex-direction: column;
        align-items: flex-start;
    }
    
    .shift-control input[type="range"] {
        width: 100%;
    }
}