/* =========================================================
   How Computers Measure Storage
   Storage Unit Ladder Laboratory
   Secondary Computer Science 1.4.1
   ========================================================= */

/* ---------------------------------------------------------
   General lesson diagrams
   --------------------------------------------------------- */

.storage-unit-calculation {
    width: fit-content;
    max-width: 100%;

    margin: 1rem auto;
    padding: 0.85rem 1.25rem;

    border: 1px solid #cbd5e1;
    border-radius: 18px;

    background: #f8fafc;
    color: #0f172a;

    font-family: "Courier New", monospace;
    font-size: 1.16rem;
    font-weight: 900;
    text-align: center;

    overflow-wrap: anywhere;
}

.storage-foundation-display {
    display: grid;
    grid-template-columns:
        minmax(150px, 1fr)
        auto
        minmax(150px, 1fr)
        auto
        minmax(180px, 1fr);

    align-items: center;
    gap: 0.8rem;

    margin: 1.5rem 0;
}

.storage-foundation-card {
    min-height: 125px;

    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.35rem;

    padding: 1rem;

    border: 1px solid #cbd5e1;
    border-radius: 20px;

    background: #f8fafc;
    color: #0f172a;

    text-align: center;
}

.storage-foundation-label {
    color: #5b5fa8;

    font-size: 0.76rem;
    font-weight: 900;
    letter-spacing: 0.08em;
    text-transform: uppercase;
}

.storage-foundation-card strong {
    font-family: "Courier New", monospace;
    font-size: 1.25rem;
    letter-spacing: 0.08em;
}

.storage-foundation-card small {
    color: #475569;
    font-weight: 700;
}

.storage-foundation-arrow {
    color: #5b5fa8;
    font-size: 1.5rem;
    font-weight: 900;
}

/* ---------------------------------------------------------
   Static storage ladder
   --------------------------------------------------------- */

.storage-unit-ladder {
    max-width: 760px;

    display: flex;
    flex-direction: column;
    gap: 0.4rem;

    margin: 1.5rem auto;
}

.storage-unit-ladder-step {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;

    padding: 0.8rem 1rem;

    border: 1px solid #cbd5e1;
    border-radius: 16px;

    background: #f8fafc;
}

.storage-unit-ladder-step strong {
    color: #5b5fa8;
    font-family: "Courier New", monospace;
    font-size: 1.1rem;
}

.storage-unit-ladder-step span {
    color: #475569;
    font-weight: 800;
}

.storage-unit-ladder-link {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 1rem;

    padding: 0.25rem 1.1rem;

    color: #64748b;
    font-size: 0.75rem;
    font-weight: 800;
}

.storage-conversion-direction {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto minmax(0, 1fr);
    align-items: stretch;
    gap: 0.8rem;

    margin: 1.5rem 0;
}

.storage-conversion-direction-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.4rem;

    padding: 1rem;

    border: 1px solid #cbd5e1;
    border-radius: 20px;

    background: #f8fafc;
    text-align: center;
}

.storage-conversion-direction-card span {
    color: #64748b;
    font-size: 0.76rem;
    font-weight: 900;
    text-transform: uppercase;
}

.storage-conversion-direction-card strong {
    color: #5b5fa8;
    font-size: 1.35rem;
}

.storage-conversion-direction-card p {
    margin: 0;
    color: #475569;
}

.storage-conversion-direction-arrow {
    display: flex;
    align-items: center;
    justify-content: center;

    color: #5b5fa8;
    font-size: 1.6rem;
    font-weight: 900;
}

/* =========================================================
   Main widget shell
   ========================================================= */

.storage-unit-widget {
    margin: 1.5rem 0;
    padding: 1.35rem;

    border: 1px solid #dbe3ef;
    border-radius: 24px;

    background:
        radial-gradient(
            circle at top right,
            rgba(91, 95, 168, 0.13),
            transparent 30%
        ),
        radial-gradient(
            circle at bottom left,
            rgba(230, 0, 79, 0.05),
            transparent 28%
        ),
        white;

    color: #0f172a;

    box-shadow: 0 16px 42px rgba(15, 23, 42, 0.08);
}

.storage-unit-widget-header {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 1rem;

    margin-bottom: 1.25rem;
}

.storage-unit-widget-header h3 {
    margin: 0.2rem 0 0;
}

.storage-unit-widget-eyebrow {
    margin: 0;

    color: #5b5fa8;
    font-size: 0.75rem;
    font-weight: 900;
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.storage-unit-widget-summary-card {
    min-width: 245px;

    display: flex;
    flex-direction: column;
    align-items: center;

    padding: 0.85rem 1rem;

    border: 1px solid #cbd5e1;
    border-radius: 18px;

    background: #f8fafc;
}

.storage-unit-widget-summary-card span {
    color: #64748b;
    font-size: 0.72rem;
    font-weight: 900;
    text-transform: uppercase;
}

.storage-unit-widget-summary-card strong {
    margin: 0.18rem 0;

    color: #5b5fa8;

    font-family: "Courier New", monospace;
    font-size: 1.35rem;
    font-weight: 900;
    text-align: center;

    overflow-wrap: anywhere;
}

.storage-unit-widget-summary-card small {
    color: #334155;
    font-weight: 800;
    text-align: center;
}

/* =========================================================
   Inputs and actions
   ========================================================= */

.storage-unit-widget-input-grid {
    display: grid;
    grid-template-columns: minmax(180px, 0.8fr) repeat(2, minmax(190px, 1fr));
    gap: 0.8rem;

    margin-bottom: 1rem;
}

.storage-unit-widget-input-card {
    display: flex;
    flex-direction: column;
    gap: 0.5rem;

    padding: 1rem;

    border: 1px solid #e2e8f0;
    border-radius: 18px;

    background: #f8fafc;
}

.storage-unit-widget-input-card label,
.storage-unit-widget-answer-area label {
    color: #475569;
    font-size: 0.84rem;
    font-weight: 800;
}

.storage-unit-widget-input-card input,
.storage-unit-widget-input-card select,
.storage-unit-widget-answer-area input {
    width: 100%;
    box-sizing: border-box;

    padding: 0.76rem 0.85rem;

    border: 1px solid #cbd5e1;
    border-radius: 13px;

    background: white;
    color: #0f172a;

    font-size: 1rem;
    font-weight: 800;

    outline: none;
}

.storage-unit-widget-input-card input,
.storage-unit-widget-answer-area input {
    font-family: "Courier New", monospace;
}

.storage-unit-widget-input-card input:focus,
.storage-unit-widget-input-card select:focus,
.storage-unit-widget-answer-area input:focus {
    border-color: #5b5fa8;

    box-shadow: 0 0 0 4px rgba(91, 95, 168, 0.12);
}

.storage-unit-widget-input-card small {
    color: #64748b;
    font-size: 0.78rem;
    font-weight: 700;
}

.storage-unit-widget-actions,
.storage-unit-widget-challenge-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.55rem;
}

.storage-unit-widget-actions {
    margin: 1rem 0;
}

.storage-unit-widget-actions button:disabled {
    opacity: 0.45;
    cursor: default;
    transform: none;
}

/* =========================================================
   Feedback
   ========================================================= */

.storage-unit-widget-feedback {
    margin: 1rem 0;
    padding: 0.8rem 1rem;

    border: 1px solid #bfdbfe;
    border-radius: 16px;

    background: #eff6ff;
    color: #1e3a8a;

    font-weight: 800;
}

.storage-unit-widget-feedback.success {
    border-color: #bbf7d0;
    background: #f0fdf4;
    color: #166534;
}

.storage-unit-widget-feedback.error {
    border-color: #fed7aa;
    background: #fff7ed;
    color: #9a3412;
}

/* =========================================================
   Interactive ladder
   ========================================================= */

.storage-unit-widget-ladder-card {
    padding: 1rem;

    border: 1px solid #e2e8f0;
    border-radius: 20px;

    background: #f8fafc;
}

.storage-unit-widget-ladder-heading {
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
    gap: 1rem;

    margin-bottom: 0.9rem;
}

.storage-unit-widget-ladder-heading h4 {
    margin: 0;
}

.storage-unit-widget-legend {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;

    color: #475569;
    font-size: 0.74rem;
    font-weight: 800;
}

.storage-unit-widget-legend span {
    display: inline-flex;
    align-items: center;
    gap: 0.3rem;
}

.storage-unit-widget-legend i {
    display: inline-block;

    width: 15px;
    height: 15px;

    border-radius: 5px;
}

.storage-unit-legend-start {
    border: 1px solid #60a5fa;
    background: #eff6ff;
}

.storage-unit-legend-path {
    border: 1px solid #c4b5fd;
    background: #f5f3ff;
}

.storage-unit-legend-target {
    border: 1px solid #4ade80;
    background: #f0fdf4;
}

.storage-unit-widget-ladder {
    display: grid;
    grid-template-columns:
        minmax(78px, 1fr) auto
        minmax(78px, 1fr) auto
        minmax(78px, 1fr) auto
        minmax(78px, 1fr) auto
        minmax(78px, 1fr) auto
        minmax(78px, 1fr) auto
        minmax(78px, 1fr) auto
        minmax(92px, 1fr) auto
        minmax(70px, 1fr);

    align-items: center;
    gap: 0.28rem;

    overflow-x: auto;
    padding-bottom: 0.5rem;
}

.storage-unit-widget-ladder-step {
    min-height: 73px;

    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.18rem;

    padding: 0.55rem;

    border: 2px solid #cbd5e1;
    border-radius: 14px;

    background: white;
    color: #0f172a;

    cursor: pointer;

    transition:
        transform 0.2s ease,
        border-color 0.2s ease,
        background 0.2s ease,
        box-shadow 0.2s ease;
}

.storage-unit-widget-ladder-step:hover {
    border-color: #5b5fa8;
    transform: translateY(-2px);
}

.storage-unit-widget-ladder-step strong {
    font-family: "Courier New", monospace;
    font-size: 0.95rem;
}

.storage-unit-widget-ladder-step span {
    color: #64748b;
    font-size: 0.63rem;
    font-weight: 800;
    text-align: center;
}

.storage-unit-widget-ladder-step.start-unit {
    border-color: #60a5fa;
    background: #eff6ff;
    color: #1e3a8a;
}

.storage-unit-widget-ladder-step.path-unit {
    border-color: #c4b5fd;
    background: #f5f3ff;
    color: #5b21b6;
}

.storage-unit-widget-ladder-step.target-unit {
    border-color: #4ade80;
    background: #f0fdf4;
    color: #166534;
}

.storage-unit-widget-ladder-step.active-step {
    border-color: #e6004f;

    background: #fff1f5;
    color: #9f1239;

    transform: translateY(-5px) scale(1.04);

    box-shadow:
        0 12px 24px rgba(230, 0, 79, 0.15),
        0 0 0 4px rgba(230, 0, 79, 0.08);
}

.storage-unit-widget-ladder-link {
    min-width: 34px;

    display: flex;
    align-items: center;
    justify-content: center;

    padding: 0.35rem 0.2rem;

    border-radius: 999px;

    color: #64748b;
    font-size: 0.62rem;
    font-weight: 900;
    text-align: center;

    transition:
        background 0.2s ease,
        color 0.2s ease,
        transform 0.2s ease;
}

.storage-unit-widget-ladder-link::before {
    content: "↔";
    margin-right: 0.15rem;
}

.storage-unit-widget-ladder-link.path-link {
    background: #ede9fe;
    color: #5b21b6;
}

.storage-unit-widget-ladder-link.active-link {
    background: #ffe4ec;
    color: #be123c;
    transform: scale(1.08);
}

/* =========================================================
   Process list
   ========================================================= */

.storage-unit-widget-process-card {
    margin: 1rem 0;
    padding: 1rem;

    border: 1px solid #e2e8f0;
    border-radius: 20px;

    background: #f8fafc;
}

.storage-unit-widget-process-card h4 {
    margin-top: 0;
}

.storage-unit-widget-process-list {
    margin-bottom: 0;
    padding-left: 1.5rem;
}

.storage-unit-widget-process-list li {
    margin: 0.45rem 0;
    padding: 0.4rem 0.55rem;

    border-radius: 10px;

    color: #475569;

    transition:
        background 0.2s ease,
        color 0.2s ease,
        transform 0.2s ease;
}

.storage-unit-widget-process-list li.active {
    background: #fff1f5;
    color: #9f1239;
    font-weight: 900;

    transform: translateX(5px);
}

.storage-unit-widget-process-list li.completed {
    background: #f0fdf4;
    color: #166534;
}

/* =========================================================
   Data cards and explanation
   ========================================================= */

.storage-unit-widget-data-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(0, 1fr));
    gap: 0.75rem;

    margin: 1rem 0;
}

.storage-unit-widget-data-card,
.storage-unit-widget-explanation-card {
    padding: 0.9rem;

    border: 1px solid #cbd5e1;
    border-radius: 18px;

    background: #f8fafc;
}

.storage-unit-widget-data-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.25rem;
}

.storage-unit-widget-data-card span,
.storage-unit-widget-explanation-card span {
    color: #64748b;
    font-size: 0.7rem;
    font-weight: 900;
    text-transform: uppercase;
}

.storage-unit-widget-data-card strong,
.storage-unit-widget-explanation-card strong {
    color: #0f172a;
    font-family: "Courier New", monospace;
    text-align: center;
    overflow-wrap: anywhere;
}

.storage-unit-widget-explanation-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.35rem;

    margin-bottom: 1rem;
}

.storage-unit-widget-explanation-card.same-unit {
    border-color: #bfdbfe;
    background: #eff6ff;
}

.storage-unit-widget-explanation-card.multi-step {
    border-color: #ddd6fe;
    background: #f5f3ff;
}

/* =========================================================
   Challenge
   ========================================================= */

.storage-unit-widget-challenge {
    display: grid;
    grid-template-columns: minmax(0, 1.2fr) minmax(260px, 0.8fr);
    gap: 1rem;

    padding: 1rem;

    border: 1px solid #e9d5ff;
    border-radius: 20px;

    background: #faf5ff;
    color: #581c87;
}

.storage-unit-widget-challenge h4 {
    margin: 0.15rem 0 0.45rem;
}

.storage-unit-widget-answer-area {
    display: grid;
    grid-template-columns: minmax(0, 1fr) auto;
    align-items: end;
    gap: 0.55rem;
}

.storage-unit-widget-answer-area label {
    grid-column: 1 / -1;
}

.storage-unit-widget-answer-area > span {
    padding: 0.75rem 0.5rem;

    color: #581c87;
    font-family: "Courier New", monospace;
    font-weight: 900;
}

.storage-unit-widget-challenge-actions,
.storage-unit-widget-challenge-message {
    grid-column: 1 / -1;
}

.storage-unit-widget-challenge-message {
    margin: 0;

    font-size: 0.88rem;
    font-weight: 800;
}

.storage-unit-widget-challenge-message.success {
    color: #166534;
}

.storage-unit-widget-challenge-message.error {
    color: #9a3412;
}

/* =========================================================
   Responsive rules
   ========================================================= */

@media (max-width: 1100px) {
    .storage-unit-widget-input-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .storage-unit-widget-input-card:first-child {
        grid-column: 1 / -1;
    }

    .storage-unit-widget-ladder {
        min-width: 1040px;
    }
}

@media (max-width: 900px) {
    .storage-foundation-display,
    .storage-conversion-direction {
        grid-template-columns: 1fr;
    }

    .storage-foundation-arrow,
    .storage-conversion-direction-arrow {
        transform: rotate(90deg);
        text-align: center;
    }

    .storage-unit-widget-data-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .storage-unit-widget-challenge {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 760px) {
    .storage-unit-widget-header,
    .storage-unit-widget-ladder-heading {
        flex-direction: column;
    }

    .storage-unit-widget-summary-card {
        width: 100%;
        box-sizing: border-box;
    }

    .storage-unit-widget-input-grid {
        grid-template-columns: 1fr;
    }

    .storage-unit-widget-input-card:first-child {
        grid-column: auto;
    }
}

@media (max-width: 520px) {
    .storage-unit-widget-data-grid {
        grid-template-columns: 1fr;
    }

    .storage-unit-widget-answer-area {
        grid-template-columns: 1fr;
    }

    .storage-unit-widget-answer-area > span {
        padding: 0;
    }
}