:root {
    --color-primary: hsl(185, 50%, 90%);
    --color-secondary: hsl(185, 50%, 10%);
    --color-tertiary: hsl(245, 80%, 20%);
    --color-accent: hsl(125, 80%, 20%);
    --color-card: hsl(185, 50%, 98%);
    
    /* shadows */
    --shadow-s: inset 0 1px 2px #ffffff30, 0 1px 2px #00000030, 0 2px 4px #00000015;
}

.dark {
    --color-primary: hsl(185, 50%, 10%);
    --color-secondary: hsl(185, 50%, 90%);
    --color-tertiary: hsl(245, 80%, 80%);
    --color-accent: hsl(125, 80%, 80%);
    --color-card: hsl(185, 50%, 20%);
    --shadow-s: inset 0 1px 2px #ffffff15, 0 1px 2px #00000050, 0 2px 4px #00000030;
}




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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--color-primary);
    min-height: 100vh;
    padding: 40px 20px;
    color: var(--color-secondary);
    border-radius: 10px;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    border-radius: 10px;
}

h1 {
    text-align: center;
    color: var(--color-secondary);
    margin-bottom: 40px;
    font-size: 1.8em;
    font-weight: 1000;
    letter-spacing: -0.5px;
}

section {
    background: var(--color-card);
    border-radius: 10px;
    padding: 30px;
    margin-bottom: 16px;
    box-shadow: var(--shadow-s);
}

/* Graph Section */
#myChart {
    max-height: 280px;
    justify-content: center;
}

canvas {
    filter: brightness(1);
}

/* Inputs Section */
#days {
    display: flex;
    justify-content: space-evenly;
    flex-wrap: wrap;
    gap: 12px;
    margin-bottom: 32px;
}

.day {
    flex: 1;
    min-width: 75px;
}

.day label {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 8px;
    font-weight: 400;
    color: var(--color-secondary);
    margin-bottom: 5px;
    font-size: 14px;
}

input {
    border: 2px solid transparent;
    background-color: var(--color-card);
    color: var(--color-secondary);
    border-radius: 10px;
    transition: ease-in-out 0.2s;
    box-shadow: var(--shadow-s);
}

input:focus {
    outline: none;
    border-color: var(--color-tertiary);
    transition: ease-in-out 0.2s;
}

input:hover {
    box-shadow: var(--shadow-s);
}

.day input {
    width: 100%;
    padding: 8px;
    font-size: 15px;
    text-align: center;
}


.goal-section {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 20px;
    flex-wrap: wrap;
}

.goal-section label {
    font-weight: 400;
    color: var(--color-secondary);
    font-size: 15px;
}

#goal-mileage {
    flex: 1;
    min-width: 150px;
    padding: 10px;
    font-size: 15px;
    box-shadow: var(--shadow-s);
}

#calculate-button {
    width: 100%;
    padding: 12px;
    background: var(--color-accent);
    color: var(--color-primary);
    border: none;
    border-radius: 16px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    transition: ease-in-out 100ms;
    box-shadow: var(--shadow-s);
}

#calculate-button:hover {
    opacity: 0.9;
    box-shadow: var(--shadow-s);
    transition: ease-in-out 100ms;
}

/* Outputs Section */
#output-section {
    text-align: center;
    background: var(--color-card);
    box-shadow: var(--shadow-s);
}

#output-section h3 {
    font-size: 1em;
    font-weight: 400;
    color: var(--color-secondary);
    margin-bottom: 5px;
}

#remaining-mileage {
    font-weight: 700;
    font-size: 2em;
    color: var(--color-secondary);
}

@media (max-width: 768px) {
    h1 {
        font-size: 1.5em;
    }

    section {
        padding: 20px;
    }

    #days {
        gap: 10px;
    }
}

footer {
    margin-top: 40px;
    padding: 20px;
    text-align: center;
    color: var(--color-secondary);
    opacity: 0.5;
    font-size: 14px;
}

/* Dark Mode Overrides */
body.dark {
    background: var(--color-primary);
    color: var(--color-secondary);
}
.container.dark {
    color: var(--color-card);
}

body.dark h1 {
    color: var(--color-secondary);
}

body.dark .day label {
    color: var(--color-secondary);
}

body.dark canvas {
    filter: brightness(0.9);
}