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

:root {
    --bg-color: #ffffff;
    --text-color: #000000;
    --border-color: #000000;
    --hover-bg: #000000;
    --hover-text: #ffffff;
}

body {
    font-family: 'Courier New', Courier, monospace;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    padding: 10px;
    transition: background-color 0.2s, color 0.2s;
}

body.dark-mode {
    --bg-color: #000000;
    --text-color: #ffffff;
    --border-color: #ffffff;
    --hover-bg: #ffffff;
    --hover-text: #000000;
}

.container {
    max-width: 800px;
    margin: 0 auto;
}

.header-wrapper {
    position: relative;
    margin-bottom: 20px;
}

h1 {
    font-size: 20px;
    font-weight: normal;
    margin-bottom: 20px;
    text-align: center;
    border-bottom: 1px solid var(--border-color);
    padding-bottom: 10px;
}

.theme-toggle {
    position: absolute;
    top: 0;
    right: 0;
    font-family: 'Courier New', Courier, monospace;
    font-size: 16px;
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-color);
    cursor: pointer;
    outline: none;
    -webkit-tap-highlight-color: transparent;
    text-transform: uppercase;
    letter-spacing: 1px;
    font-size: 12px;
}

.theme-toggle:hover,
.theme-toggle:focus,
.theme-toggle:active {
    background-color: var(--hover-bg);
    color: var(--hover-text);
}

.selector-section {
    margin-bottom: 20px;
    padding: 15px;
    border: 1px solid var(--border-color);
}

.icon-selector-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 10px;
    margin-bottom: 15px;
}

.icon-btn {
    font-family: 'Courier New', Courier, monospace;
    font-size: 14px;
    padding: 15px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-color);
    cursor: pointer;
    outline: none;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 5px;
    transition: none;
    min-height: 70px;
}

.icon-btn:hover,
.icon-btn:focus {
    background-color: var(--hover-bg);
    color: var(--hover-text);
}

.icon-btn.active {
    background-color: var(--hover-bg);
    color: var(--hover-text);
}

.icon {
    font-size: 24px;
    line-height: 1;
}

.icon-label {
    font-size: 11px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.reverse-btn {
    font-family: 'Courier New', Courier, monospace;
    font-size: 12px;
    padding: 10px 20px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-color);
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 1px;
    width: 100%;
    outline: none;
    -webkit-tap-highlight-color: transparent;
}

.reverse-btn:hover,
.reverse-btn:focus,
.reverse-btn:active {
    background-color: var(--hover-bg);
    color: var(--hover-text);
}

.converter-container {
    margin-top: 20px;
}

.converter-section {
    margin-bottom: 20px;
}

.converter-group {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
    padding: 15px;
    border: 1px solid var(--border-color);
}

.input-group {
    display: flex;
    flex-direction: column;
}

.output-group {
    display: flex;
    flex-direction: column;
}

label {
    font-size: 12px;
    margin-bottom: 5px;
    text-transform: uppercase;
    letter-spacing: 1px;
}

input[type="number"] {
    font-family: 'Courier New', Courier, monospace;
    font-size: 16px;
    padding: 12px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-color);
    outline: none;
    -webkit-appearance: none;
    -moz-appearance: textfield;
    width: 100%;
}

input[type="number"]:focus {
    border: 2px solid var(--border-color);
}

input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.output-wrapper {
    display: flex;
    align-items: center;
    gap: 10px;
}

.output {
    font-family: 'Courier New', Courier, monospace;
    font-size: 14px;
    padding: 8px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-color);
    min-height: 36px;
    flex: 1;
    display: flex;
    align-items: center;
}

.copy-btn {
    font-family: 'Courier New', Courier, monospace;
    font-size: 11px;
    padding: 8px 12px;
    border: 1px solid var(--border-color);
    background-color: var(--bg-color);
    color: var(--text-color);
    cursor: pointer;
    text-transform: uppercase;
    letter-spacing: 1px;
    white-space: nowrap;
    outline: none;
    -webkit-tap-highlight-color: transparent;
    min-height: 36px;
}

.copy-btn:hover,
.copy-btn:focus,
.copy-btn:active {
    background-color: var(--hover-bg);
    color: var(--hover-text);
}

@media (max-width: 600px) {
    body {
        padding: 10px 5px;
    }
    
    h1 {
        font-size: 18px;
        margin-bottom: 15px;
        padding-bottom: 8px;
        padding-right: 50px;
    }
    
    .theme-toggle {
        font-size: 11px;
        padding: 6px 10px;
    }
    
    .container {
        max-width: 100%;
    }
    
    .selector-section {
        padding: 10px;
        margin-bottom: 15px;
    }
    
    .icon-selector-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 8px;
        margin-bottom: 12px;
    }
    
    .icon-btn {
        padding: 12px;
        min-height: 60px;
    }
    
    .icon {
        font-size: 20px;
    }
    
    .icon-label {
        font-size: 10px;
    }
    
    .converter-group {
        grid-template-columns: 1fr;
        padding: 12px;
        gap: 12px;
    }
    
    .output-wrapper {
        flex-direction: column;
        align-items: stretch;
        gap: 8px;
    }
    
    .copy-btn {
        width: 100%;
    }
    
    input[type="number"] {
        font-size: 16px;
        padding: 12px;
    }
    
    .output {
        font-size: 14px;
        padding: 12px;
        min-height: 44px;
    }
    
    label {
        font-size: 11px;
    }
}