:root {
    --paper: #f5efe3;
    --paper-strong: #fffaf2;
    --ink: #172534;
    --ink-soft: #496072;
    --line: rgba(23, 37, 52, 0.12);
    --accent: #0f766e;
    --accent-soft: #d8efe9;
    --warm: #c16a3a;
    --warm-soft: #f5ddcf;
    --gold: #b58a23;
    --shadow: 0 24px 60px rgba(23, 37, 52, 0.08);
    --radius: 24px;
}

* {
    box-sizing: border-box;
}

html,
body {
    margin: 0;
    min-height: 100%;
}

body {
    font-family: "Aptos", "Trebuchet MS", sans-serif;
    color: var(--ink);
    background:
        radial-gradient(circle at top left, rgba(15, 118, 110, 0.08), transparent 30%),
        radial-gradient(circle at bottom right, rgba(193, 106, 58, 0.09), transparent 25%),
        linear-gradient(180deg, #f8f4eb 0%, #efe5d5 100%);
}

.ambient {
    position: fixed;
    inset: auto;
    z-index: 0;
    pointer-events: none;
    border-radius: 999px;
    filter: blur(50px);
}

.ambient-a {
    width: 18rem;
    height: 18rem;
    top: 5%;
    right: 6%;
    background: rgba(15, 118, 110, 0.08);
}

.ambient-b {
    width: 14rem;
    height: 14rem;
    bottom: 12%;
    left: 5%;
    background: rgba(193, 106, 58, 0.12);
}

.site-shell {
    position: relative;
    z-index: 1;
    max-width: 1220px;
    margin: 0 auto;
    padding: 1.5rem;
}

.topbar {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    margin-bottom: 1.5rem;
    padding: 1rem 1.25rem;
    background: rgba(255, 250, 242, 0.78);
    backdrop-filter: blur(18px);
    border: 1px solid rgba(255, 255, 255, 0.7);
    border-radius: 999px;
    box-shadow: var(--shadow);
}

.brand {
    display: inline-flex;
    align-items: center;
    gap: 0.9rem;
    color: inherit;
    text-decoration: none;
}

.brand-mark {
    display: inline-grid;
    place-items: center;
    width: 2.9rem;
    height: 2.9rem;
    border-radius: 1rem;
    background: linear-gradient(135deg, var(--accent), #164e63);
    color: #fff;
    font-family: "Iowan Old Style", Georgia, serif;
    font-size: 1.3rem;
    box-shadow: 0 16px 32px rgba(15, 118, 110, 0.24);
}

.brand strong,
h1,
h2,
h3 {
    font-family: "Iowan Old Style", Georgia, serif;
    letter-spacing: -0.02em;
}

.brand small {
    display: block;
    color: var(--ink-soft);
    font-size: 0.82rem;
}

.topnav {
    display: flex;
    flex-wrap: wrap;
    gap: 0.75rem;
}

.topnav a {
    color: var(--ink);
    text-decoration: none;
    font-weight: 600;
}

.topnav .logout-link {
    color: var(--warm);
}

.page-frame {
    display: flex;
    flex-direction: column;
    gap: 1.5rem;
}

.hero,
.page-header,
.dashboard-grid,
.section-stack,
.chapter-grid,
.assignment-list,
.notebook-flow,
.flash {
    display: grid;
    gap: 1.25rem;
}

.hero {
    grid-template-columns: minmax(0, 1.3fr) minmax(320px, 0.8fr);
    align-items: start;
}

.hero h1,
.page-header h1 {
    margin: 0 0 0.75rem;
    font-size: clamp(2.2rem, 5vw, 4.5rem);
    line-height: 0.96;
}

.hero-text,
.section-text,
.muted {
    color: var(--ink-soft);
}

.hero-copy,
.paper-card,
.focus-warning {
    padding: 1.5rem;
    border-radius: var(--radius);
    border: 1px solid var(--line);
    background: rgba(255, 250, 242, 0.92);
    box-shadow: var(--shadow);
}

.flash {
    padding: 1rem 1.25rem;
    border-radius: 1rem;
    border: 1px solid var(--line);
    box-shadow: var(--shadow);
}

.flash-success {
    background: rgba(15, 118, 110, 0.1);
    color: var(--accent);
}

.flash-info {
    background: rgba(23, 37, 52, 0.06);
    color: var(--ink);
}

.flash-warning {
    background: rgba(181, 138, 35, 0.12);
    color: #7d6112;
}

.paper-card {
    position: relative;
    overflow: hidden;
}

.paper-card::after {
    content: "";
    position: absolute;
    inset: 0;
    background: linear-gradient(140deg, rgba(255, 255, 255, 0.35), transparent 55%);
    pointer-events: none;
}

.feature-grid,
.dashboard-grid,
.chapter-grid {
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
}

.feature-card,
.stat-card,
.chapter-card,
.assignment-card,
.notebook-block {
    display: grid;
    gap: 1rem;
}

.login-panel {
    position: sticky;
    top: 1.5rem;
}

.login-group {
    display: grid;
    gap: 0.8rem;
    margin-top: 1.25rem;
}

.login-card,
.button-link {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.5rem;
    padding: 0.9rem 1rem;
    border-radius: 1rem;
    border: none;
    background: linear-gradient(135deg, var(--accent), #13576f);
    color: #fff;
    text-decoration: none;
    font-weight: 700;
    cursor: pointer;
}

.login-card {
    flex-direction: column;
    align-items: flex-start;
    background: linear-gradient(180deg, rgba(15, 118, 110, 0.08), rgba(255, 255, 255, 0.6));
    color: var(--ink);
    border: 1px solid rgba(15, 118, 110, 0.12);
}

.button-link.subtle,
.button-link.ghost {
    background: rgba(15, 118, 110, 0.08);
    color: var(--accent);
}

.button-link.ghost {
    border: 1px solid rgba(15, 118, 110, 0.18);
}

.eyebrow {
    margin: 0 0 0.55rem;
    color: var(--warm);
    font-size: 0.78rem;
    font-weight: 800;
    letter-spacing: 0.15em;
    text-transform: uppercase;
}

.headline-metric {
    display: grid;
    align-content: center;
    justify-items: end;
    gap: 0.35rem;
    min-width: 10rem;
}

.headline-metric span,
.big-progress,
.metric-row strong {
    font-family: "Iowan Old Style", Georgia, serif;
    font-size: clamp(2rem, 4vw, 3.4rem);
}

.metric-row {
    display: flex;
    align-items: baseline;
    justify-content: space-between;
    gap: 0.75rem;
}

.progress-bar {
    width: 100%;
    height: 0.8rem;
    border-radius: 999px;
    background: rgba(23, 37, 52, 0.08);
    overflow: hidden;
}

.progress-bar span {
    display: block;
    height: 100%;
    border-radius: inherit;
    background: linear-gradient(90deg, var(--accent), #0ea5a0);
}

.inline-stats {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(110px, 1fr));
    gap: 0.8rem;
    margin: 0;
}

.inline-stats div {
    padding: 0.9rem;
    border-radius: 1rem;
    background: rgba(23, 37, 52, 0.04);
}

.inline-stats dt {
    color: var(--ink-soft);
    font-size: 0.85rem;
}

.inline-stats dd {
    margin: 0.25rem 0 0;
    font-size: 1.3rem;
    font-weight: 800;
}

.highlighted-card {
    background:
        linear-gradient(120deg, rgba(15, 118, 110, 0.1), rgba(255, 250, 242, 0.95) 35%),
        rgba(255, 250, 242, 0.92);
}

.split-header,
.chapter-foot,
.assignment-meta,
.assignment-side,
.exercise-actions {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
    flex-wrap: wrap;
}

.align-right {
    text-align: right;
}

.assignment-list,
.section-stack {
    gap: 1rem;
}

.assignment-card.wide,
.teacher-grid {
    grid-template-columns: 1fr;
}

.assignment-side {
    align-items: flex-end;
    flex-direction: column;
}

.chip {
    display: inline-flex;
    align-items: center;
    padding: 0.38rem 0.7rem;
    border-radius: 999px;
    font-size: 0.82rem;
    font-weight: 700;
}

.chip-success {
    background: rgba(15, 118, 110, 0.12);
    color: var(--accent);
}

.chip-warning {
    background: rgba(181, 138, 35, 0.16);
    color: var(--gold);
}

.chip-muted {
    background: rgba(23, 37, 52, 0.08);
    color: var(--ink-soft);
}

.chip-accent {
    background: rgba(193, 106, 58, 0.14);
    color: var(--warm);
}

.notebook-flow {
    position: relative;
}

.notebook-flow::before {
    content: "";
    position: absolute;
    top: 0;
    bottom: 0;
    left: 1.7rem;
    width: 2px;
    background: linear-gradient(180deg, rgba(15, 118, 110, 0.28), rgba(193, 106, 58, 0.18));
}

.notebook-block {
    margin-left: 1.8rem;
}

.notebook-block::before {
    content: "";
    position: absolute;
    top: 2rem;
    left: -1.85rem;
    width: 0.95rem;
    height: 0.95rem;
    border-radius: 999px;
    background: var(--paper-strong);
    border: 3px solid var(--accent);
    box-shadow: 0 0 0 8px rgba(15, 118, 110, 0.08);
}

.evaluation-block::before {
    border-color: var(--gold);
}

.course-panel,
.assignment-panel,
.exercise-layout {
    display: grid;
    gap: 1rem;
}

.exercise-layout {
    grid-template-columns: 1fr;
}

.code-label {
    display: grid;
    gap: 0.55rem;
}

textarea {
    width: 100%;
    padding: 1rem;
    border: 1px solid rgba(23, 37, 52, 0.12);
    border-radius: 1rem;
    background: #101924;
    color: #f6f7f7;
    font-family: Consolas, "Cascadia Mono", monospace;
    line-height: 1.55;
    resize: vertical;
}

.assert-panel {
    padding: 1rem;
    border-radius: 1rem;
    background: rgba(15, 118, 110, 0.06);
}

.assert-list {
    list-style: none;
    padding: 0;
    margin: 0;
    display: grid;
    gap: 0.65rem;
}

.assert-list li {
    display: grid;
    gap: 0.2rem;
    padding: 0.75rem 0.9rem;
    border-radius: 0.9rem;
}

.assert-pass {
    background: rgba(15, 118, 110, 0.1);
}

.assert-fail {
    background: rgba(193, 106, 58, 0.12);
}

.focus-warning {
    border-color: rgba(181, 138, 35, 0.35);
    background: rgba(255, 244, 215, 0.92);
    color: #6f5611;
}

.section-heading {
    display: grid;
    gap: 0.35rem;
}

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

    .topbar,
    .split-header,
    .assignment-side,
    .headline-metric {
        align-items: flex-start;
        justify-items: start;
        text-align: left;
    }

    .notebook-flow::before {
        left: 0.95rem;
    }

    .notebook-block {
        margin-left: 1rem;
    }

    .notebook-block::before {
        left: -1.15rem;
    }
}