:root {
    --background-color-light: #f4f7f9;
    --text-color-light: #333;
    --card-background-light: #ffffff;
    --header-background-light: #2c3e50;
    --header-text-light: #ffffff;
    --button-background-light: #3498db;
    --button-hover-light: #2980b9;
    --border-color-light: #ddd;
    --shadow-color-light: rgba(0, 0, 0, 0.1);
    --tech-font: 'Consolas', 'Courier New', monospace;
    --highlight-color: #e74c3c;
}

.dark-mode {
    --background-color-light: #121212;
    --text-color-light: #e0e0e0;
    --card-background-light: #1e1e1e;
    --header-background-light: #000000;
    --header-text-light: #00ff99;
    --button-background-light: #00aaff;
    --button-hover-light: #0077cc;
    --border-color-light: #333;
    --shadow-color-light: rgba(0, 255, 153, 0.2); 
}

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

body {
    font-family: var(--tech-font);
    background-color: var(--background-color-light);
    color: var(--text-color-light);
    transition: background-color 0.5s, color 0.5s;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 20px;
    flex-grow: 1;
}

.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--header-background-light);
    color: var(--header-text-light);
    padding: 15px 20px;
    margin-bottom: 30px;
    border-radius: 8px;
    box-shadow: 0 4px 10px var(--shadow-color-light);
    border: 1px solid var(--header-text-light); 
}

.header h1 {
    font-size: 1.5rem;
    letter-spacing: 1px;
}

#theme-toggle {
    background: none;
    border: 2px solid var(--header-text-light);
    color: var(--header-text-light);
    padding: 10px;
    border-radius: 50%;
    cursor: pointer;
    font-size: 1.2rem;
    transition: background-color 0.3s, color 0.3s, transform 0.3s;
}

#theme-toggle:hover {
    background-color: var(--header-text-light);
    color: var(--header-background-light);
    transform: rotate(15deg);
}

.calculator-card {
    background-color: var(--card-background-light);
    padding: 30px;
    border-radius: 12px;
    box-shadow: 0 6px 15px var(--shadow-color-light);
    border: 1px solid var(--border-color-light);
}

.calculator-card h2 {
    text-align: center;
    margin-bottom: 25px;
    color: var(--highlight-color);
}

.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: bold;
    color: var(--text-color-light);
}

.input-group input {
    width: 100%;
    padding: 12px;
    border: 1px solid var(--border-color-light);
    border-radius: 6px;
    background-color: transparent; 
    color: var(--text-color-light);
    font-family: var(--tech-font);
    font-size: 1rem;
    transition: border-color 0.3s, box-shadow 0.3s;
}

.input-group input:focus {
    border-color: var(--button-background-light);
    outline: none;
    box-shadow: 0 0 5px var(--button-background-light);
}

#calcular-btn {
    width: 100%;
    padding: 15px;
    background-color: var(--button-background-light);
    color: var(--header-text-light);
    border: none;
    border-radius: 6px;
    font-size: 1.1rem;
    font-weight: bold;
    cursor: pointer;
    transition: background-color 0.3s, transform 0.2s;
    margin-top: 10px;
}

#calcular-btn:hover {
    background-color: var(--button-hover-light);
    transform: translateY(-2px);
}

.result-container {
    margin-top: 30px;
    padding-top: 20px;
    border-top: 2px dashed var(--border-color-light);
    text-align: center;
    animation: fadeIn 0.8s ease-out;
}

.result-container h3 {
    margin-bottom: 15px;
    color: var(--button-background-light);
}

.result-value {
    font-size: 2.5rem;
    font-weight: bold;
    color: var(--highlight-color);
    margin-bottom: 10px;
}

.result-classification {
    font-size: 1.5rem;
    font-weight: 600;
    margin-bottom: 20px;
    padding: 5px 10px;
    border-radius: 4px;
    display: inline-block;
    color: var(--text-color-light);
    background-color: rgba(var(--highlight-color), 0.1); 
}

.table-container {
    margin-top: 20px;
    text-align: left;
}

.table-container h4 {
    margin-bottom: 10px;
    text-align: center;
    color: var(--button-background-light);
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.9rem;
}

table th, table td {
    border: 1px solid var(--border-color-light);
    padding: 10px;
    text-align: left;
}

table th {
    background-color: var(--header-background-light);
    color: var(--header-text-light);
    font-weight: bold;
}

.highlight-row {
    background-color: var(--highlight-color) !important;
    color: var(--card-background-light);
    font-weight: bold;
}

.error-message {
    color: var(--highlight-color);
    margin-top: 15px;
    text-align: center;
    font-weight: bold;
}

.hidden {
    display: none;
}

.footer {
    text-align: center;
    padding: 15px;
    margin-top: 20px;
    font-size: 0.8rem;
    background-color: var(--header-background-light);
    color: var(--header-text-light);
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.dark-mode .calculator-card {
    border: 1px solid var(--button-background-light); 
}

.dark-mode .input-group input:focus {
    box-shadow: 0 0 8px var(--button-background-light);
}

@media (max-width: 600px) {
    
    .container {
        padding: 10px; 
    }

    .header {
        flex-direction: column; 
        text-align: center;
        padding: 10px;
    }

    .header h1 {
        font-size: 1.2rem; 
        margin-bottom: 10px;
    }

    #theme-toggle {
        padding: 8px; 
        font-size: 1rem;
    }

    .calculator-card {
        padding: 20px; 
    }

    .calculator-card h2 {
        font-size: 1.3rem;
    }
    
    .input-group label, .input-group input {
        font-size: 0.9rem;
    }

    #calcular-btn {
        padding: 12px; 
        font-size: 1rem;
    }

    /* Resultados */
    .result-value {
        font-size: 2rem; 
    }
    .result-classification {
        font-size: 1.2rem; 
    }

    /* Tabela */
    table {
        font-size: 0.8rem; 
    }
    table th, table td {
        padding: 8px;
    }
}

@media (max-width: 400px) {
    .header h1 {
        font-size: 1rem;
        letter-spacing: normal;
    }
    
    table, thead, tbody, th, td, tr { 
        display: block; 
    }

    thead tr { 
        position: absolute;
        top: -9999px;
        left: -9999px;
    }

    tr { 
        border: 1px solid var(--border-color-light);
        margin-bottom: 5px;
    }

    td { 
        border: none;
        border-bottom: 1px solid var(--border-color-light);
        position: relative;
        padding-left: 50%;
        text-align: right;
    }

    td:before {
        position: absolute;
        top: 6px;
        left: 6px;
        width: 45%;
        padding-right: 10px;
        white-space: nowrap;
        text-align: left;
        font-weight: bold;
    }

    td:nth-of-type(1):before { content: "IMC (kg/m²):"; }
    td:nth-of-type(2):before { content: "Classificação:"; }

    .highlight-row {
        margin-top: 10px;
    }
}