html {
    scroll-behavior: smooth;
}

body {
    min-width: 320px;
    margin: 0;
    color: var(--color-ink);
    background:
        radial-gradient(circle at 15% 0%, rgb(183 121 0 / 10%), transparent 28rem),
        var(--color-page);
    font-family: var(--font-family-base);
    font-size: 16px;
    line-height: 1.5;
}

select,
fieldset {
    font: inherit;
}

select:focus-visible {
    outline: 3px solid rgb(183 121 0 / 30%);
    outline-offset: 3px;
}

.hero {
    padding: 18px 24px 16px;
    text-align: center;
    background: rgb(255 255 255 / 90%);
    border-bottom: 1px solid var(--color-line);
    box-shadow: 0 2px 7px rgb(32 31 34 / 7%);
    backdrop-filter: blur(14px);
}

.hero__content {
    width: min(760px, 100%);
    margin: 0 auto;
}

h1,
h2 {
    margin: 0;
    line-height: 1.08;
    letter-spacing: -0.035em;
}

h1 {
    font-size: clamp(2rem, 5vw, 3rem);
}

h2 {
    font-size: clamp(1.35rem, 3vw, 1.8rem);
}

.hero__subtitle {
    margin: 4px 0 0;
    color: var(--color-muted);
    font-size: clamp(0.95rem, 2vw, 1.08rem);
    font-weight: 600;
}

.hero__rule {
    display: none;
    width: 64px;
    height: 5px;
    margin: 24px auto 20px;
    background: var(--color-primary);
    border-radius: 999px;
}

.hero__description {
    display: none;
}

.packing-app {
    display: grid;
    grid-template-columns: minmax(420px, 1.4fr) minmax(300px, 0.8fr);
    gap: 20px;
    width: min(1280px, calc(100% - 32px));
    margin: 12px auto 36px;
}

.viewer-panel {
    grid-column: 1;
    grid-row: 1;
}

.controls-panel {
    grid-column: 2;
    grid-row: 1;
}

.panel,
.results,
.assumption-note {
    background: var(--color-surface);
    border: 1px solid rgb(32 31 34 / 5%);
    border-radius: var(--radius-card);
    box-shadow: var(--shadow-low);
}

.panel {
    padding: 24px;
}

.section-heading {
    display: flex;
    gap: 18px;
    align-items: flex-start;
    justify-content: space-between;
    margin-bottom: 18px;
}

form,
fieldset {
    display: grid;
    gap: 12px;
}

form {
    gap: 14px;
}

fieldset {
    padding: 0;
    margin: 0;
    border: 0;
}

#custom-box-fields[hidden] {
    display: none;
}

.fieldset-legend {
    margin: 0;
    color: #6f531b;
    font-size: 1.0rem;
    font-weight: 800;
    letter-spacing: 0.12em;
    text-transform: uppercase;
}

.fieldset-heading {
    display: flex;
    gap: 18px;
    align-items: end;
    justify-content: space-between;
}

.unit-field {
    width: auto;
}

.unit-field select {
    min-height: 40px;
}

.field-grid {
    display: grid;
    grid-template-columns: repeat(3, minmax(0, 1fr));
    gap: 10px;
}

.field-grid.field-grid--4 {
    grid-template-columns: repeat(4, minmax(0, 1fr));
}

.field-grid.field-grid--2 {
    grid-template-columns: 1fr minmax(140px, 1fr);
}

.field {
    display: grid;
    gap: 5px;
}

.field__label {
    color: #6f531b;
    font-size: 0.72rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.field--wide > .field__label {
    font-size: 1.0rem;
}

.field input,
.field select {
    width: 100%;
    min-height: 42px;
    padding: 0 13px;
    color: var(--color-ink);
    font-weight: 700;
    background: #fffaf0;
    border: 1px solid transparent;
    border-bottom: 3px solid #777179;
    border-radius: 12px 12px 3px 3px;
    transition:
        background-color var(--transition),
        border-color var(--transition);
}

/* Remove number input spinner arrows */
.field input[type="number"]::-webkit-outer-spin-button,
.field input[type="number"]::-webkit-inner-spin-button {
    -webkit-appearance: none;
    margin: 0;
}

.field input[type="number"] {
    -moz-appearance: textfield;
}

.field input:focus,
.field select:focus {
    background: var(--color-primary-soft);
    border-bottom-color: var(--color-primary);
    outline: 0;
}

.field__support {
    min-height: 1.4em;
    color: var(--color-muted);
    font-size: 0.82rem;
}

.form-message {
    min-height: 1.5em;
    margin: 10px 0 0;
    color: #17623b;
    font-size: 0.88rem;
    font-weight: 650;
}

.form-message.is-error {
    color: #a1251e;
}

.viewer-panel {
    display: flex;
    flex-direction: column;
    min-width: 0;
}

.viewer-heading {
    align-items: end;
}

.viewer-hint {
    margin: 0;
    color: var(--color-muted);
    font-size: 0.82rem;
}

#packing-viewer {
    position: relative;
    flex: 1;
    width: 100%;
    min-height: 520px;
    overflow: hidden;
    background:
        linear-gradient(rgb(255 255 255 / 45%), rgb(255 255 255 / 45%)),
        #fffaf0;
    border: 1px solid var(--color-line);
    border-radius: 20px;
}

#packing-viewer canvas {
    display: block;
    width: 100%;
    height: 100%;
}

.viewer-placeholder {
    position: absolute;
    z-index: 1;
    top: 50%;
    left: 50%;
    width: min(280px, calc(100% - 48px));
    color: var(--color-muted);
    text-align: center;
    transform: translate(-50%, -50%);
}

.results {
    display: grid;
    grid-template-columns: 1.1fr repeat(3, 1fr);
    gap: 12px;
    grid-column: 1 / -1;
    grid-row: 2;
    padding: 14px;
}

.results-heading,
.metric-card {
    padding: 14px;
}

.results-heading {
    align-self: center;
}

.metric-card {
    min-width: 0;
    background: #fff8e6;
    border-radius: 20px;
    transition:
        color var(--transition),
        background-color var(--transition),
        box-shadow var(--transition);
}

.metric-card--weight-warning {
    background: #ffe2a8;
    box-shadow: inset 0 0 0 2px #d97706;
}

.metric-card--weight-warning .metric-card__label,
.metric-card--weight-warning .metric-card__value {
    color: #92400e;
}

.metric-card--weight-critical {
    background: #b42318;
    box-shadow:
        inset 0 0 0 3px #7a1410,
        0 6px 18px rgb(180 35 24 / 30%);
}

.metric-card--weight-critical .metric-card__label,
.metric-card--weight-critical .metric-card__value,
.metric-card--weight-critical .metric-card__detail {
    color: #ffffff;
}

.metric-card--weight-critical .metric-card__value {
    font-size: clamp(1.55rem, 3vw, 2.2rem);
}

.metric-card__label,
.metric-card__detail {
    margin: 0;
}

.metric-card__label {
    color: #6f531b;
    font-size: 0.72rem;
    font-weight: 800;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.metric-card__value {
    display: block;
    margin: 5px 0 4px;
    overflow-wrap: anywhere;
    color: var(--color-primary-dark);
    font-size: clamp(1.35rem, 2.6vw, 1.9rem);
    font-weight: 800;
    line-height: 1;
    letter-spacing: -0.04em;
}

.metric-card__detail {
    color: var(--color-muted);
    font-size: 0.8rem;
}

.assumption-note {
    grid-column: 1 / -1;
    padding: 18px 24px;
    color: #5e5961;
    font-size: 0.88rem;
}

.assumption-note strong {
    color: var(--color-ink);
}

.page-footer {
    display: grid;
    gap: 6px;
    width: min(1280px, calc(100% - 32px));
    padding: 0 0 36px;
    margin: 0 auto;
    color: var(--color-muted);
    text-align: center;
    font-size: 0.88rem;
}

.page-footer p {
    margin: 0;
}

.page-footer strong {
    color: var(--color-ink);
}

.page-footer a {
    color: var(--color-primary-dark);
    font-weight: 700;
}

.page-footer a:hover {
    color: var(--color-primary);
}

@media (max-width: 900px) {
    .packing-app {
        grid-template-columns: 1fr;
    }

    .controls-panel,
    .viewer-panel {
        grid-column: auto;
    }

    .controls-panel {
        grid-row: 1;
    }

    .viewer-panel {
        grid-row: 2;
    }

    .results {
        grid-row: 3;
        grid-template-columns: repeat(3, 1fr);
    }

    .results-heading {
        grid-column: 1 / -1;
    }
}

@media (max-width: 640px) {
    .hero {
        padding: 14px 20px 12px;
    }

    .packing-app {
        width: min(100% - 20px, 1280px);
        margin-top: 14px;
    }

    .panel {
        padding: 22px;
        border-radius: 22px;
    }

    .section-heading {
        display: grid;
    }

    .fieldset-heading {
        align-items: start;
    }

    .field-grid,
    .results {
        grid-template-columns: 1fr;
    }

    .results-heading {
        grid-column: auto;
    }

    #packing-viewer {
        min-height: 400px;
    }
}

@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }
}