:root {
    --color-bg: #f4f7f9;
    --color-surface: #ffffff;
    --color-text: #16232c;
    --color-text-muted: #556575;
    --color-border: #dce3e8;
    --color-primary: #0a6ebd;
    --color-primary-text: #ffffff;
    --color-secondary: #e8eef2;
    --color-secondary-text: #16232c;

    --color-excellent: #1f8f4e;
    --color-good: #2f9bd6;
    --color-fair: #d6a92f;
    --color-poor: #d6742f;
    --color-very-poor: #c23b3b;

    --radius: 10px;
    --spacing-1: 4px;
    --spacing-2: 8px;
    --spacing-3: 16px;
    --spacing-4: 24px;
    --spacing-5: 32px;

    color-scheme: light;
}

@media (prefers-color-scheme: dark) {
    :root {
        --color-bg: #10171d;
        --color-surface: #182430;
        --color-text: #e8eef2;
        --color-text-muted: #9fb0bd;
        --color-border: #2b3a47;
        --color-primary: #3fa9f5;
        --color-primary-text: #08131a;
        --color-secondary: #223140;
        --color-secondary-text: #e8eef2;

        /* Tells the browser to render native form controls (the date
           input's calendar icon, checkboxes, scrollbars) with a dark-mode
           palette instead of the default dark icon that's invisible on a
           dark background. */
        color-scheme: dark;
    }
}

* {
    box-sizing: border-box;
}

html {
    /* Prevent iOS Safari from auto-enlarging text in landscape/orientation changes. */
    -webkit-text-size-adjust: 100%;
    text-size-adjust: 100%;
}

html, body {
    margin: 0;
    padding: 0;
    /* A single overlong token (e.g. a raw pasted URL) must never force the page to scroll sideways. */
    overflow-x: hidden;
    width: 100%;
}

body {
    background: var(--color-bg);
    color: var(--color-text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.5;
    -webkit-tap-highlight-color: transparent;
}

h1, h2, h3 {
    line-height: 1.2;
    margin: 0 0 var(--spacing-2);
}

p {
    margin: 0 0 var(--spacing-2);
}

a {
    color: var(--color-primary);
}

.panel {
    background: var(--color-surface);
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: var(--spacing-4);
    /* Belt-and-suspenders: a panel's content (long narrative text, chart
       labels) must clip/wrap inside the panel rather than push page width. */
    max-width: 100%;
    overflow-wrap: break-word;
}

.field-row {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-1);
    margin-bottom: var(--spacing-3);
}

.field-row label {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--color-text-muted);
}

input[type="text"],
input[type="date"] {
    /* 16px minimum keeps iOS Safari from auto-zooming the page on focus. */
    font-size: 16px;
    padding: 10px 12px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    background: var(--color-bg);
    color: var(--color-text);
    width: 100%;
    min-height: 44px;
    touch-action: manipulation;
}

/* Fallback for browsers that don't fully honor color-scheme on the icon:
   force-invert the native calendar icon so it's visible on a dark input. */
@media (prefers-color-scheme: dark) {
    input[type="date"]::-webkit-calendar-picker-indicator {
        filter: invert(1);
    }
}

.btn {
    font-size: 1rem;
    font-weight: 600;
    padding: 12px 20px;
    min-height: 44px;
    min-width: 44px;
    border-radius: var(--radius);
    border: 1px solid transparent;
    cursor: pointer;
    touch-action: manipulation;
}

.btn-primary {
    background: var(--color-primary);
    color: var(--color-primary-text);
}

.btn-secondary {
    background: var(--color-secondary);
    color: var(--color-secondary-text);
    margin-top: var(--spacing-2);
}

.btn-toggle {
    background: var(--color-bg);
    color: var(--color-text);
    border-color: var(--color-border);
}

.btn-toggle.active {
    background: var(--color-primary);
    color: var(--color-primary-text);
    border-color: var(--color-primary);
}

.btn-large {
    width: 100%;
    font-size: 1.1rem;
    margin-top: var(--spacing-2);
}

.hint {
    font-size: 0.85rem;
    color: var(--color-text-muted);
}

.form-error {
    color: var(--color-very-poor);
    font-weight: 600;
    margin-top: var(--spacing-2);
}

.site-header,
.site-footer {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--spacing-4);
}

.tagline {
    color: var(--color-text-muted);
}

.site-footer p {
    font-size: 0.8rem;
    color: var(--color-text-muted);
}

/* Small phones (e.g. 375px-wide devices): claw back padding so content
   has more usable width, and support notches/home-indicators. */
@media (max-width: 480px) {
    :root {
        --spacing-4: 16px;
        --spacing-5: 20px;
    }

    .site-header,
    .site-footer {
        padding-left: max(var(--spacing-3), env(safe-area-inset-left));
        padding-right: max(var(--spacing-3), env(safe-area-inset-right));
    }
}