/* Material Design (M1 — https://m1.material.io) visual language:
   Roboto type, an Indigo/Pink palette, flat surfaces on a paper
   metaphor (elevation via shadow, not borders), 2dp corner radius,
   and underlined text fields. */

:root {
    color-scheme: light;

    /* Palette */
    --primary: #43a047;
    --primary-dark: #2e7d32;
    --primary-light: #c8e6c9;
    --accent: #ff6e40;
    --accent-dark: #ff3d00;
    --on-primary: #ffffff;
    --on-accent: #ffffff;

    --bg: #fafafa;
    --surface: #ffffff;
    --divider: rgba(0, 0, 0, .12);

    --text: rgba(0, 0, 0, .87);
    --muted: rgba(0, 0, 0, .54);
    --disabled: rgba(0, 0, 0, .38);
    --hover: rgba(0, 0, 0, .04);

    --success-bg: #e8f5e9;
    --success-text: #2e7d32;
    --error-bg: #ffebee;
    --error-text: #c62828;
    --danger: #f44336;
    --danger-dark: #d32f2f;
    --developing-bg: #fff8e1;
    --developing-text: #f9a825;
    --no-data-bg: #eeeeee;
    --no-data-text: #757575;

    /* Elevation (Material shadow recipes) */
    --elevation-1: 0 1px 3px 0 rgba(0, 0, 0, .16), 0 1px 2px 0 rgba(0, 0, 0, .10);
    --elevation-2: 0 3px 4px 0 rgba(0, 0, 0, .14), 0 1px 8px 0 rgba(0, 0, 0, .12), 0 3px 3px -2px rgba(0, 0, 0, .20);
    --elevation-4: 0 4px 5px 0 rgba(0, 0, 0, .14), 0 1px 10px 0 rgba(0, 0, 0, .12), 0 2px 4px -1px rgba(0, 0, 0, .20);

    --radius: 2px;
}

* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: Roboto, -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
    background: var(--bg);
    color: var(--text);
    -webkit-font-smoothing: antialiased;
}

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

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

.site-header {
    background: var(--primary);
    box-shadow: var(--elevation-4);
    position: sticky;
    top: 0;
    z-index: 10;
}

.main-nav {
    max-width: 1100px;
    margin: 0 auto;
    padding: 0 1.5rem;
    height: 64px;
    display: flex;
    align-items: center;
    gap: 1.5rem;
}

.main-nav a {
    color: rgba(255, 255, 255, .7);
    text-decoration: none;
    font-size: 0.9rem;
    font-weight: 500;
    letter-spacing: 0.03em;
    text-transform: uppercase;
    height: 64px;
    display: inline-flex;
    align-items: center;
    border-bottom: 3px solid transparent;
    transition: color .15s ease, border-color .15s ease;
}

.main-nav a.brand {
    font-weight: 700;
    color: var(--on-primary);
    text-transform: none;
    letter-spacing: normal;
    font-size: 1.25rem;
    margin-right: 0.5rem;
    border-bottom: none;
}

.main-nav a:hover,
.main-nav a.active {
    color: var(--on-primary);
}

.main-nav a.active {
    border-bottom-color: var(--accent);
}

.logout-form {
    margin-left: auto;
}

.link-button {
    background: none;
    border: none;
    color: rgba(255, 255, 255, .7);
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    padding: 0;
    transition: color .15s ease;
}

.link-button:hover {
    color: var(--on-primary);
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
}

h1 {
    margin-top: 0;
    font-size: 1.75rem;
    font-weight: 500;
    letter-spacing: -0.01em;
}

.flash {
    padding: 0.9rem 1.1rem;
    border-radius: var(--radius);
    margin-bottom: 1.5rem;
    font-size: 0.95rem;
    box-shadow: var(--elevation-1);
}

.flash-success {
    background: var(--success-bg);
    color: var(--success-text);
}

.flash-error {
    background: var(--error-bg);
    color: var(--error-text);
}

.hint {
    font-size: 0.85rem;
    color: var(--muted);
    margin: 0.25rem 0 0.75rem;
}

.hint.warning {
    color: var(--error-text);
    font-weight: 500;
}

form.inline-form,
form:not(.inline-form) {
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--elevation-1);
    padding: 1.25rem;
    margin-bottom: 1.5rem;
    display: flex;
    flex-wrap: wrap;
    align-items: end;
    gap: 1.25rem;
}

fieldset {
    border: none;
    border-top: 1px solid var(--divider);
    margin: 0;
    padding: 1rem 0 0;
}

legend {
    padding: 0 0.25rem 0 0;
    font-size: 0.8rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--muted);
}

label {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    font-size: 0.75rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    color: var(--muted);
}

label.checkbox-label {
    flex-direction: row;
    align-items: center;
    text-transform: none;
    letter-spacing: normal;
    font-size: 0.95rem;
    font-weight: 400;
    gap: 0.5rem;
    color: var(--text);
}

input[type="text"],
input[type="password"],
input[type="number"],
select,
textarea {
    font: inherit;
    font-size: 0.95rem;
    text-transform: none;
    letter-spacing: normal;
    color: var(--text);
    padding: 0.5rem 0.1rem;
    border: none;
    border-bottom: 1px solid rgba(0, 0, 0, .42);
    border-radius: 0;
    background: transparent;
    min-width: 180px;
    transition: border-color .15s ease, box-shadow .15s ease;
}

input[type="text"]:hover,
input[type="password"]:hover,
input[type="number"]:hover,
select:hover,
textarea:hover {
    border-bottom-color: var(--text);
}

input[type="text"]:focus,
input[type="password"]:focus,
input[type="number"]:focus,
select:focus,
textarea:focus {
    outline: none;
    border-bottom: 2px solid var(--accent);
    padding-bottom: calc(0.5rem - 1px);
}

input[type="file"] {
    font: inherit;
    font-size: 0.9rem;
    color: var(--text);
}

input[type="checkbox"],
input[type="radio"] {
    accent-color: var(--accent);
    width: 18px;
    height: 18px;
}

textarea {
    min-height: 4rem;
    resize: vertical;
}

button,
input[type="submit"] {
    font: inherit;
    font-size: 0.875rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    background: var(--accent);
    color: var(--on-accent);
    border: none;
    border-radius: var(--radius);
    padding: 0.65rem 1.25rem;
    cursor: pointer;
    box-shadow: var(--elevation-1);
    transition: background-color .15s ease, box-shadow .15s ease;
}

button:hover,
input[type="submit"]:hover {
    background: var(--accent-dark);
    box-shadow: var(--elevation-2);
}

button.danger {
    background: var(--danger);
}

button.danger:hover {
    background: var(--danger-dark);
}

.data-table {
    width: 100%;
    border-collapse: collapse;
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--elevation-1);
    overflow: hidden;
}

.data-table th,
.data-table td {
    text-align: left;
    padding: 0.8rem 1rem;
    border-bottom: 1px solid var(--divider);
    font-size: 0.9rem;
}

.data-table th {
    background: var(--surface);
    color: var(--muted);
    font-weight: 500;
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}

.data-table tbody tr {
    transition: background-color .1s ease;
}

.data-table tbody tr:hover {
    background: var(--hover);
}

.data-table tr:last-child td {
    border-bottom: none;
}

.stat-row {
    display: flex;
    flex-wrap: wrap;
    gap: 1rem;
    margin-bottom: 1.5rem;
}

.stat-card {
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--elevation-1);
    padding: 1.25rem 1.75rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-width: 100px;
}

.stat-card strong {
    font-size: 2rem;
    font-weight: 500;
    color: var(--primary);
}

.stat-card span {
    color: var(--muted);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.03em;
    margin-top: 0.25rem;
}

.match-grid,
.page-list {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
    gap: 1rem;
}

.match-card,
.page-card {
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--elevation-1);
    padding: 0.9rem;
    transition: box-shadow .15s ease;
}

.match-card:hover,
.page-card:hover {
    box-shadow: var(--elevation-2);
}

.match-preview img,
.page-card img {
    max-width: 100%;
    display: block;
    border-radius: var(--radius);
}

.filename {
    font-size: 0.8rem;
    color: var(--muted);
    word-break: break-all;
}

.upload-results {
    list-style: none;
    padding: 0;
    margin: 0 0 1.5rem;
    background: var(--surface);
    border-radius: var(--radius);
    box-shadow: var(--elevation-1);
}

.upload-results li {
    padding: 0.6rem 1rem;
    border-bottom: 1px solid var(--divider);
    font-size: 0.9rem;
}

.upload-results li:last-child {
    border-bottom: none;
}

.upload-results li.ok {
    color: var(--success-text);
}

.upload-results li.error {
    color: var(--error-text);
}

.file-count {
    color: var(--muted);
    font-size: 0.8rem;
}

.mastery-badge {
    display: inline-block;
    padding: 0.2rem 0.65rem;
    border-radius: 999px;
    font-size: 0.75rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.02em;
}

.mastery-badge.mastery-mastered,
td.mastery-mastered {
    background: var(--success-bg);
    color: var(--success-text);
}

.mastery-badge.mastery-developing,
td.mastery-developing {
    background: var(--developing-bg);
    color: var(--developing-text);
}

.mastery-badge.mastery-struggling,
td.mastery-struggling {
    background: var(--error-bg);
    color: var(--error-text);
}

.mastery-badge.mastery-no_data,
td.mastery-no_data {
    background: var(--no-data-bg);
    color: var(--no-data-text);
}

.mastery-badge.mastery-stale {
    background: var(--no-data-bg);
    color: var(--no-data-text);
    margin-left: 0.35rem;
}

.heatmap-wrap {
    overflow-x: auto;
}

.heatmap-table {
    white-space: nowrap;
}

td.mastery-cell {
    text-align: center;
    font-weight: 500;
}

td.mastery-cell-stale {
    box-shadow: inset 0 0 0 2px var(--no-data-text);
}

th.heatmap-category-header {
    text-align: center;
    border-left: 1px solid var(--divider);
}

.data-table form.inline-form {
    margin: 0;
    padding: 0;
    box-shadow: none;
    background: none;
    display: inline-flex;
}

.trend-bar {
    display: inline-block;
    width: 120px;
    height: 0.5rem;
    background: var(--no-data-bg);
    border-radius: 999px;
    overflow: hidden;
    vertical-align: middle;
    margin-right: 0.5rem;
}

.trend-bar-fill {
    display: block;
    height: 100%;
}

.trend-bar-fill.mastery-mastered {
    background: var(--success-text);
}

.trend-bar-fill.mastery-developing {
    background: var(--developing-text);
}

.trend-bar-fill.mastery-struggling {
    background: var(--error-text);
}

.trend-bar-fill.mastery-no_data {
    background: var(--no-data-text);
}

.hint.ai-suggestion {
    background: #fbe9e7;
    border-left: 3px solid var(--accent);
    color: rgba(0, 0, 0, .7);
    padding: 0.5rem 0.75rem;
    margin: 0.25rem 0 1rem;
    border-radius: 0 var(--radius) var(--radius) 0;
}