:root {
    --page-bg: #f8f8f8;
    --surface: #ffffff;
    --surface-soft: #f8f8f8;
    --surface-muted: #e6e6e6;
    --ink: #333333;
    --ink-soft: #666666;
    --line: #dadada;
    --line-strong: #c8c8c8;
    --brand: #005c6d;
    --brand-strong: #004854;
    --accent: #00c1cf;
    --accent-strong: #00d8e8;
    --red: #b20000;
    --red-strong: #7e0000;
    --green: #a0c340;
    --amber: #b78718;
    --warning: #fff5ea;
    --focus: rgba(0, 193, 207, 0.28);
    --shadow: 0 1px 6px rgba(0, 0, 0, 0.1);
    --shadow-strong: 0 3px 14px rgba(0, 0, 0, 0.16);
    --radius: 4px;
    --container: 1160px;
    --library-width: 1160px;
    --font-sans: "Roboto", Arial, Helvetica, sans-serif;
    --font-slab: "Roboto Slab", Georgia, serif;
}

*,
*::before,
*::after {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    min-height: 100vh;
    background: var(--page-bg);
    color: var(--ink);
    font-family: var(--font-sans);
    font-size: 16px;
    line-height: 1.5;
}

a {
    color: inherit;
    text-decoration: none;
}

button,
input {
    font: inherit;
}

button {
    color: inherit;
}

code {
    padding: 0.15rem 0.35rem;
    border-radius: 4px;
    background: var(--surface-muted);
    color: var(--red-strong);
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

.icon-sprite {
    position: absolute;
    width: 0;
    height: 0;
    overflow: hidden;
}

.icon {
    width: 1.05rem;
    height: 1.05rem;
    fill: none;
    stroke: currentColor;
    stroke-width: 2;
    stroke-linecap: round;
    stroke-linejoin: round;
    flex: 0 0 auto;
}

.ptd-shell {
    padding: 1rem 0 1.25rem;
}

.ptd-frame {
    width: min(calc(100% - 1.25rem), var(--container));
    margin: 0 auto;
    display: grid;
    gap: 0.7rem;
}

.shell-panel,
.track-section {
    background: var(--surface);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.masthead {
    display: grid;
    grid-template-columns: minmax(0, 1.18fr) minmax(0, 0.82fr);
    gap: 1rem;
    align-items: stretch;
    padding: 0.85rem 1rem;
    border-top: 4px solid var(--red);
}

.masthead > * {
    min-width: 0;
}

.brand-lockup {
    display: flex;
    align-items: center;
    gap: 0.85rem;
}

.brand-mark {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.85rem;
    height: 2.85rem;
    border-radius: var(--radius);
    background: var(--red);
    color: #ffffff;
    font-weight: 700;
    letter-spacing: 0;
}

.eyebrow,
.accordion-title small {
    margin: 0;
    color: var(--red);
    font-size: 0.77rem;
    font-weight: 700;
    letter-spacing: 0;
    text-transform: uppercase;
}

.masthead h1,
.track-heading h2,
.accordion-title strong,
.period-heading h3,
.empty-state h2 {
    margin: 0;
    color: var(--brand);
    font-family: var(--font-slab);
    letter-spacing: 0;
}

.masthead h1 {
    margin-top: 0.12rem;
    font-size: 1.65rem;
    line-height: 1.1;
}

.masthead__copy > p {
    max-width: 45rem;
    margin: 0.7rem 0 0;
    color: var(--ink-soft);
    font-size: 0.95rem;
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, minmax(5.6rem, 1fr));
    gap: 0.55rem;
    min-width: 0;
}

.stat-item {
    min-width: 0;
    min-height: 4rem;
    padding: 0.62rem 0.7rem;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface-soft);
}

.stat-item:nth-child(1) {
    border-top: 3px solid var(--brand);
}

.stat-item:nth-child(2) {
    border-top: 3px solid var(--red);
}

.stat-item:nth-child(3) {
    border-top: 3px solid var(--accent);
}

.stat-item:nth-child(4) {
    border-top: 3px solid var(--amber);
}

.stat-item strong {
    display: block;
    margin-bottom: 0.15rem;
    color: var(--brand);
    font-size: 1.35rem;
    line-height: 1;
}

.stat-item span {
    display: block;
    color: var(--ink-soft);
    font-size: 0.88rem;
    overflow-wrap: anywhere;
    hyphens: auto;
}

.control-strip {
    position: sticky;
    top: 0;
    z-index: 10;
    display: grid;
    grid-template-columns: minmax(280px, 1fr) auto auto;
    gap: 0.55rem;
    align-items: center;
    padding: 0.65rem;
}

.search-field {
    display: flex;
    align-items: center;
    gap: 0.55rem;
    min-width: 0;
    min-height: 2.55rem;
    padding: 0 0.85rem;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface-soft);
    color: var(--ink-soft);
}

.search-field:focus-within {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px var(--focus);
}

.search-field input {
    width: 100%;
    min-width: 0;
    border: 0;
    outline: 0;
    background: transparent;
    color: var(--ink);
}

.search-field input::placeholder {
    color: #7c7c7c;
}

.segment-group {
    display: inline-flex;
    align-items: center;
    gap: 0.25rem;
    padding: 0.25rem;
    border: 1px solid var(--line);
    border-radius: var(--radius);
    background: var(--surface-muted);
}

.segment-button {
    min-height: 2.05rem;
    padding: 0.34rem 0.68rem;
    border: 0;
    border-radius: 6px;
    background: transparent;
    color: var(--ink-soft);
    cursor: pointer;
    font-weight: 700;
    white-space: nowrap;
}

.segment-button:hover,
.segment-button:focus-visible {
    background: #ffffff;
    color: var(--ink);
    outline: none;
}

.segment-button.is-active {
    background: var(--brand);
    color: #ffffff;
}

.utility-buttons,
.file-actions {
    display: flex;
    flex-wrap: wrap;
    gap: 0.35rem;
}

.file-actions {
    justify-content: flex-end;
}

.tool-button,
.file-action {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.38rem;
    min-height: 2.15rem;
    padding: 0.42rem 0.68rem;
    border: 1px solid transparent;
    border-radius: var(--radius);
    background: #ffffff;
    border-color: var(--line);
    color: var(--brand);
    cursor: pointer;
    font-weight: 700;
    transition: background-color 0.18s ease, border-color 0.18s ease, color 0.18s ease;
}

.tool-button {
    font-size: 0.88rem;
}

.tool-button:hover,
.tool-button:focus-visible,
.file-action:hover,
.file-action:focus-visible {
    background: #eef7f8;
    border-color: #b9d7dc;
    color: var(--brand-strong);
    outline: none;
}

.tool-button--quiet,
.file-action--download {
    background: #ffffff;
    border-color: var(--line);
    color: var(--brand);
}

.tool-button--quiet:hover,
.tool-button--quiet:focus-visible,
.file-action--download:hover,
.file-action--download:focus-visible {
    background: #effbfd;
    color: var(--brand-strong);
}

.file-action {
    min-height: 1.72rem;
    padding: 0.22rem 0.48rem;
    border-color: transparent;
    background: transparent;
    color: var(--brand);
    font-size: 0.78rem;
    font-weight: 500;
}

.file-action--download {
    border-color: transparent;
    background: transparent;
    color: var(--ink-soft);
}

.file-action:hover,
.file-action:focus-visible,
.file-action--download:hover,
.file-action--download:focus-visible {
    background: #f1f7f8;
    border-color: #cfe2e6;
    color: var(--brand-strong);
}

.tool-button .icon {
    width: 0.92rem;
    height: 0.92rem;
}

.file-action .icon {
    width: 0.86rem;
    height: 0.86rem;
}

.results-strip {
    width: min(100%, var(--library-width));
    justify-self: center;
    padding: 0.62rem 0.85rem;
    background: #ffffff;
    border-color: var(--line);
    border-left: 4px solid var(--brand);
    box-shadow: var(--shadow);
}

.results-strip p {
    margin: 0;
    color: var(--brand);
    font-size: 0.92rem;
    font-weight: 700;
}

.library {
    display: grid;
    gap: 0.7rem;
    min-width: 0;
}

.library--centered {
    width: min(100%, var(--library-width));
    justify-self: center;
}

.track-section {
    overflow: hidden;
    box-shadow: var(--shadow);
}

.track-heading {
    display: grid;
    grid-template-columns: 1.45rem minmax(0, 1fr) auto;
    gap: 0.62rem;
    align-items: center;
    padding: 0.72rem 0.85rem;
    background: var(--surface-soft);
    border-bottom: 1px solid var(--line);
}

.track-heading h2 {
    margin-top: 0.1rem;
    font-size: 1.08rem;
}

.count-pill {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 1.45rem;
    padding: 0.16rem 0.52rem;
    border-radius: 4px;
    background: var(--brand);
    color: #ffffff;
    font-size: 0.76rem;
    font-weight: 700;
    white-space: nowrap;
}

.count-pill--soft {
    background: #e7f8fa;
    color: var(--brand-strong);
}

.tree-node {
    position: relative;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 1.05rem;
    height: 1.05rem;
    border-radius: 999px;
    border: 1px solid var(--line-strong);
    background: #ffffff;
    color: var(--brand-strong);
    font-weight: 700;
}

.tree-node::before {
    content: "";
    width: 0.4rem;
    height: 0.4rem;
    border-radius: 999px;
    background: currentColor;
}

.tree-node--track {
    border-color: rgba(178, 0, 0, 0.35);
    color: var(--red);
}

.tree-node--course {
    border-color: rgba(0, 92, 109, 0.35);
    color: var(--brand);
}

.tree-node--level {
    width: 1rem;
    height: 1rem;
    border-color: rgba(0, 193, 207, 0.35);
    color: var(--accent);
}

.tree-node--period {
    width: 0.9rem;
    height: 0.9rem;
    border-color: rgba(181, 109, 20, 0.35);
    color: var(--amber);
}

.tree-node--period::before {
    width: 0.34rem;
    height: 0.34rem;
}

.course-list {
    display: grid;
    padding: 0;
}

.course-card {
    position: relative;
}

.course-card + .course-card {
    border-top: 1px solid var(--line);
}

.accordion-toggle {
    width: 100%;
    display: grid;
    grid-template-columns: 1.45rem minmax(0, 1fr) auto 1.55rem;
    gap: 0.62rem;
    align-items: center;
    padding: 0.58rem 0.85rem;
    border: 0;
    border-left: 3px solid transparent;
    background: #ffffff;
    text-align: left;
    cursor: pointer;
}

.course-toggle.is-open {
    border-left-color: var(--brand);
    background: #fbfbfb;
}

.accordion-toggle:hover,
.accordion-toggle:focus-visible {
    background: #f8f8f8;
    outline: none;
}

.accordion-toggle::after {
    content: "";
    width: 0.5rem;
    height: 0.5rem;
    justify-self: center;
    border-right: 2px solid currentColor;
    border-bottom: 2px solid currentColor;
    color: var(--brand);
    transform: rotate(45deg);
    transition: transform 0.18s ease;
}

.accordion-toggle.is-open::after {
    transform: rotate(225deg);
}

.accordion-title {
    min-width: 0;
}

.accordion-title strong {
    display: block;
    margin-top: 0.1rem;
    overflow-wrap: anywhere;
    font-size: 0.94rem;
    line-height: 1.25;
}

.course-toggle .accordion-title strong {
    font-size: 0.98rem;
}

.accordion-panel {
    display: none;
}

.accordion-panel.is-open {
    display: block;
}

.course-panel {
    background: #ffffff;
    border-top: 1px solid var(--line);
}

.level-list {
    position: relative;
    display: grid;
    padding: 0.42rem 0.85rem 0.5rem 2.35rem;
}

.level-list::before {
    content: "";
    position: absolute;
    top: 0.45rem;
    bottom: 0.55rem;
    left: 1.55rem;
    border-left: 1px solid #d8e1e4;
}

.level-block {
    position: relative;
    border: 0;
    background: transparent;
    overflow: visible;
}

.level-block::before {
    content: "";
    position: absolute;
    top: 1.1rem;
    left: -0.8rem;
    width: 0.58rem;
    border-top: 1px solid #d8e1e4;
}

.level-block + .level-block {
    margin-top: 0.22rem;
}

.level-toggle {
    grid-template-columns: 1.25rem minmax(0, 1fr) auto 1.45rem;
    padding: 0.52rem 0.7rem;
    border: 1px solid var(--line);
    border-left-color: #b9d7dc;
    border-radius: var(--radius);
    background: #ffffff;
}

.level-toggle.is-open {
    background: #fbfbfb;
    border-bottom-right-radius: 0;
    border-bottom-left-radius: 0;
}

.level-panel {
    position: relative;
    margin-bottom: 0.25rem;
    padding: 0.2rem 0 0.24rem 1.15rem;
    border: 1px solid var(--line);
    border-top: 0;
    border-bottom-right-radius: var(--radius);
    border-bottom-left-radius: var(--radius);
    background: #ffffff;
}

.level-panel::before {
    content: "";
    position: absolute;
    top: 0.35rem;
    bottom: 0.45rem;
    left: 0.6rem;
    border-left: 1px solid #e0e5e7;
}

.period-block + .period-block {
    border-top: 0;
}

.period-block {
    position: relative;
}

.period-block::before {
    content: "";
    position: absolute;
    top: 1rem;
    left: -0.55rem;
    width: 0.44rem;
    border-top: 1px solid #e0e5e7;
}

.period-heading {
    display: grid;
    grid-template-columns: 1.15rem minmax(0, 1fr) auto;
    gap: 0.5rem;
    align-items: center;
    padding: 0.42rem 0.7rem 0.42rem 0;
    background: #ffffff;
}

.period-heading h3 {
    color: var(--brand-strong);
    font-size: 0.88rem;
}

.period-heading span:last-child {
    color: var(--ink-soft);
    font-size: 0.76rem;
    font-weight: 700;
    white-space: nowrap;
}

.file-list {
    display: grid;
    margin: 0;
    padding: 0 0 0.18rem 1.15rem;
    list-style: none;
}

.file-row {
    display: grid;
    grid-template-columns: 2.55rem minmax(0, 1fr) auto;
    gap: 0.65rem;
    align-items: center;
    padding: 0.56rem 0.7rem;
    border-top: 1px solid var(--line);
}

.file-row:hover {
    background: #f8f8f8;
}

.file-type {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 2.25rem;
    min-height: 1.55rem;
    border-radius: 4px;
    background: #f3e0dd;
    color: var(--red-strong);
    font-size: 0.68rem;
    font-weight: 700;
}

.file-main {
    min-width: 0;
}

.file-main strong {
    display: block;
    color: var(--brand);
    font-size: 0.92rem;
    overflow-wrap: anywhere;
}

.file-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.25rem;
    margin-top: 0.28rem;
}

.file-meta span {
    display: inline-flex;
    align-items: center;
    min-height: 1.2rem;
    padding: 0.06rem 0.36rem;
    border: 1px solid var(--line);
    border-radius: 999px;
    background: var(--surface-soft);
    color: var(--ink-soft);
    font-size: 0.72rem;
    font-weight: 500;
}

.empty-state {
    padding: 1.5rem;
    text-align: center;
}

.empty-state h2 {
    margin-bottom: 0.45rem;
    font-size: 1.25rem;
}

.empty-state p {
    margin: 0;
    color: var(--ink-soft);
}

.empty-state--warning {
    background: var(--warning);
}

[hidden] {
    display: none !important;
}

@media (max-width: 1120px) {
    .masthead,
    .control-strip {
        grid-template-columns: 1fr;
    }

    .segment-group {
        width: 100%;
        overflow-x: auto;
    }
}

@media (max-width: 760px) {
    .ptd-shell {
        padding-top: 0.65rem;
    }

    .ptd-frame {
        width: min(calc(100% - 0.8rem), var(--container));
        gap: 0.65rem;
    }

    .masthead {
        padding: 0.9rem;
    }

    .brand-lockup {
        align-items: flex-start;
    }

    .brand-mark {
        width: 2.6rem;
        height: 2.6rem;
    }

    .masthead h1 {
        font-size: 1.42rem;
    }

    .stats-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .control-strip {
        position: static;
        padding: 0.65rem;
    }

    .utility-buttons,
    .file-actions {
        width: 100%;
    }

    .tool-button,
    .file-action {
        flex: 1 1 6.5rem;
    }

    .track-heading {
        grid-template-columns: 1.35rem minmax(0, 1fr);
    }

    .track-heading .count-pill {
        grid-column: 2;
        justify-self: start;
    }

    .accordion-toggle {
        grid-template-columns: 1.35rem minmax(0, 1fr) 1.45rem;
    }

    .accordion-toggle .count-pill {
        grid-column: 2 / -1;
        justify-self: start;
    }

    .accordion-toggle::after {
        grid-column: 3;
        grid-row: 1;
    }

    .level-list {
        padding-left: 0.65rem;
        padding-right: 0.65rem;
    }

    .period-heading {
        grid-template-columns: 1.15rem minmax(0, 1fr);
    }

    .period-heading span:last-child {
        grid-column: 2;
    }

    .file-row {
        grid-template-columns: 2.45rem minmax(0, 1fr);
        align-items: start;
    }

    .file-actions {
        grid-column: 1 / -1;
    }
}

@media (max-width: 480px) {
    .stats-grid {
        grid-template-columns: 1fr;
    }

    .segment-button {
        padding-left: 0.65rem;
        padding-right: 0.65rem;
    }
}