/* ==============================
   1. Grundeinstellungen
================================= */

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --bg-main: #190b17;
    --bg-sidebar: #101624;
    --bg-card: #151e2e;
    --bg-card-hover: #1b2639;

    --text-primary: #f1f5f9;
    --text-secondary: #94a3b8;

    --accent: #818cf8;
    --accent-hover: #6366f1;

    --border: #263247;
}

body {
    font-family: "Segoe UI", Arial, sans-serif;
    background: var(--bg-main);
    color: var(--text-primary);
    min-height: 100vh;
}

/* ==============================
   2. Sidebar
================================= */

.sidebar {
    position: fixed;
    top: 0;
    left: 0;
    width: 250px;
    height: 100vh;
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border);
    padding: 30px 20px;

    display: flex;
    flex-direction: column;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 55px;
}

.logo span {
    background: var(--accent);
    color: white;
    font-weight: bold;
    padding: 10px;
    border-radius: 10px;
}

.logo h1 {
    font-size: 21px;
    letter-spacing: 0.5px;
}

.nav-heading {
    color: var(--text-secondary);
    font-size: 11px;
    font-weight: bold;
    letter-spacing: 1.5px;
    margin-bottom: 15px;
    padding-left: 12px;
}

.sidebar nav a {
    display: block;
    text-decoration: none;
    color: var(--text-secondary);
    padding: 13px 14px;
    margin-bottom: 7px;
    border-radius: 9px;
    transition: 0.2s;
}

.sidebar nav a:hover {
    background: var(--bg-card-hover);
    color: var(--text-primary);
}

.sidebar nav a.active {
    background: rgba(129, 140, 248, 0.15);
    color: var(--accent);
}

.sidebar-footer {
    margin-top: auto;
    color: var(--text-secondary);
    font-size: 12px;
    line-height: 1.8;
    padding-left: 10px;
}

/* ==============================
   3. Hauptbereich
================================= */

.content {
    margin-left: 250px;
    padding: 35px 45px;
    max-width: 1600px;
}

.topbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
}

.topbar h2 {
    font-size: 26px;
    margin-bottom: 6px;
}

.topbar p {
    color: var(--text-secondary);
    font-size: 14px;
}

.user-avatar {
    width: 42px;
    height: 42px;
    background: var(--accent);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: bold;
}

/* ==============================
   4. Willkommensbereich
================================= */

.welcome {
    background: linear-gradient(120deg, #202b49, #171d35);
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 40px;
    margin-bottom: 40px;
}

.eyebrow {
    color: var(--accent);
    font-size: 11px;
    font-weight: bold;
    letter-spacing: 2px;
}

.welcome h2 {
    font-size: 34px;
    line-height: 1.3;
    margin: 15px 0;
}

.welcome p {
    color: var(--text-secondary);
    font-size: 15px;
}

/* ==============================
   5. Karteikartenbereich
================================= */

.flashcard-section {
    max-width: 750px;
}

.section-heading {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 20px;
    margin-bottom: 20px;
}

.section-heading h3 {
    font-size: 19px;
    margin-bottom: 6px;
}

.section-heading p {
    color: var(--text-secondary);
    font-size: 13px;
}

.category {
    color: var(--accent);
    background: rgba(129, 140, 248, 0.12);
    padding: 8px 12px;
    border-radius: 20px;
    font-size: 11px;
    white-space: nowrap;
}

/* ==============================
   6. Karteikarte
================================= */

.flashcard {
    height: 340px;
    perspective: 1000px;
    cursor: pointer;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.7s;
    transform-style: preserve-3d;
}

.flashcard.flipped .flashcard-inner {
    transform: rotateY(180deg);
}

.flashcard-front,
.flashcard-back {
    position: absolute;
    inset: 0;
    padding: 35px;
    border-radius: 18px;
    background: var(--bg-card);
    border: 1px solid var(--border);

    display: flex;
    flex-direction: column;
    justify-content: center;

    backface-visibility: hidden;
    -webkit-backface-visibility: hidden;
}

.flashcard-back {
    transform: rotateY(180deg);
    background: #19243a;
}

.card-label {
    color: var(--accent);
    font-size: 11px;
    font-weight: bold;
    letter-spacing: 2px;
    margin-bottom: 25px;
}

.flashcard h2 {
    font-size: 32px;
    margin-bottom: 10px;
}

.flashcard h3 {
    font-size: 19px;
    color: var(--text-secondary);
    margin-bottom: 20px;
}

.flashcard p {
    color: var(--text-secondary);
    line-height: 1.7;
    font-size: 15px;
}

.flashcard small {
    color: var(--accent);
    margin-top: 25px;
    font-size: 12px;
}

/* ==============================
   7. Mobile-Ansicht
================================= */

@media (max-width: 800px) {
    .sidebar {
        width: 75px;
        padding: 20px 10px;
    }

    .logo {
        justify-content: center;
        margin-bottom: 40px;
    }

    .logo h1,
    .nav-heading,
    .sidebar nav a:not(.active),
    .sidebar-footer {
        display: none;
    }

    .sidebar nav a {
        font-size: 0;
        text-align: center;
        padding: 15px 5px;
    }

    .sidebar nav a.active {
        font-size: 0;
    }

    .content {
        margin-left: 75px;
        padding: 25px 18px;
    }

    .welcome {
        padding: 25px;
    }

    .welcome h2 {
        font-size: 25px;
    }

    .section-heading {
        align-items: flex-start;
        flex-direction: column;
    }

    .flashcard {
        height: 380px;
    }
}

/* Navigation der Karteikarten */

.card-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 25px;
    margin-top: 25px;
}

.card-controls button {
    background: var(--accent);
    color: white;
    border: none;
    padding: 12px 22px;
    border-radius: 8px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: background 0.2s, opacity 0.2s;
}

.card-controls button:hover:not(:disabled) {
    background: var(--accent-hover);
}

.card-controls button:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

#card-counter {
    color: var(--text-secondary);
    font-size: 14px;
}

/* Lernfortschritt */

.learning-actions {
    display: flex;
    justify-content: center;
    gap: 15px;
    margin-top: 20px;
}

.learning-actions button {
    padding: 12px 24px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg-card);
    color: var(--text-primary);
    font-size: 14px;
    cursor: pointer;
    transition: 0.2s;
}

.learning-actions button:hover:not(:disabled) {
    background: var(--bg-card-hover);
    border-color: var(--accent);
}

.learning-actions button:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

#known-card {
    background: var(--accent);
    border-color: var(--accent);
}

#known-card:hover:not(:disabled) {
    background: var(--accent-hover);
}

.learning-status {
    max-width: 500px;
    margin: 30px auto 0;
}

.progress-info {
    display: flex;
    justify-content: space-between;
    margin-bottom: 10px;
    color: var(--text-secondary);
    font-size: 13px;
}

.progress-track {
    height: 8px;
    background: var(--border);
    border-radius: 10px;
    overflow: hidden;
}

#progress-fill {
    width: 0%;
    height: 100%;
    background: var(--accent);
    border-radius: 10px;
    transition: width 0.3s ease;
}

/* Kartenübersicht */

.overview-section {
    margin-bottom: 45px;
}

.card-search {
    display: flex;
    gap: 12px;
    margin: 20px 0;
}

.card-search input,
.card-search select {
    background: var(--bg-card);
    color: var(--text-primary);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 13px 15px;
    font-size: 14px;
}

.card-search input {
    flex: 1;
    min-width: 0;
}

.card-search select {
    min-width: 190px;
}

.card-list {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 12px;
}

.card-list-item {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    gap: 7px;
    padding: 18px;
    text-align: left;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 10px;
    color: var(--text-primary);
    cursor: pointer;
    transition: 0.2s;
}

.card-list-item:hover {
    background: var(--bg-card-hover);
    border-color: var(--accent);
}

.card-list-item span,
.card-list-item small {
    color: var(--text-secondary);
}

.card-list-item small {
    font-size: 11px;
}

.card-list-item.is-learned {
    border-color: #4ade80;
}

@media (max-width: 600px) {
    .card-search {
        flex-direction: column;
    }

    .card-search select {
        width: 100%;
    }
}

/* Kartenverwaltung */

.admin-section {
    margin-bottom: 45px;
}

.admin-form {
    display: flex;
    flex-direction: column;
    gap: 10px;
    max-width: 650px;
    padding: 22px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 12px;
}

.admin-form label {
    color: var(--text-secondary);
    font-size: 13px;
    margin-top: 8px;
}

.admin-form input,
.admin-form select,
.admin-form textarea {
    width: 100%;
    box-sizing: border-box;
    padding: 12px;
    background: var(--bg-main);
    color: var(--text-primary);
    border: 1px solid var(--border);
    border-radius: 7px;
    font: inherit;
}

.admin-form textarea {
    min-height: 90px;
    resize: vertical;
}

.admin-buttons {
    display: flex;
    gap: 12px;
    margin-top: 15px;
}

.admin-buttons button {
    padding: 12px 18px;
    border: none;
    border-radius: 7px;
    background: var(--accent);
    color: white;
    cursor: pointer;
}

.admin-buttons button:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

#delete-card {
    background: #b91c1c;
}

#admin-message {
    color: var(--text-secondary);
    font-size: 13px;
}


/* =========================
   ANMELDUNG / REGISTRIERUNG
========================= */

.auth-overlay {
    position: fixed;
    inset: 0;
    z-index: 1000;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    background: rgba(5, 9, 18, 0.96);
}

.auth-box {
    width: 100%;
    max-width: 420px;
    padding: 36px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 16px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.4);
}

.auth-logo {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 32px;
}

.auth-logo span {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 42px;
    height: 42px;
    border-radius: 12px;
    background: var(--accent);
    color: white;
    font-weight: 700;
}

.auth-logo h2 {
    margin: 0;
    color: var(--text-primary);
}

.auth-box h3 {
    margin-bottom: 8px;
    color: var(--text-primary);
    font-size: 24px;
}

.auth-box > p {
    color: var(--text-secondary);
}

#login-form {
    display: flex;
    flex-direction: column;
    gap: 12px;
    margin-top: 24px;
}

#login-form label {
    color: var(--text-secondary);
    font-size: 14px;
}

#login-form input {
    width: 100%;
    padding: 13px 14px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--bg-main);
    color: var(--text-primary);
    font: inherit;
}

#login-form input:focus {
    outline: 2px solid var(--accent);
    border-color: transparent;
}

#auth-submit {
    margin-top: 12px;
    padding: 13px;
    border: none;
    border-radius: 8px;
    background: var(--accent);
    color: white;
    font-weight: 600;
    cursor: pointer;
}

#auth-submit:hover {
    background: var(--accent-hover);
}

#auth-toggle {
    margin-top: 20px;
    padding: 0;
    border: none;
    background: transparent;
    color: var(--accent);
    cursor: pointer;
    font: inherit;
}

#auth-message {
    margin-top: 12px;
    font-size: 14px;
}

.logout-button {
    width: calc(100% - 30px);
    margin: 20px 15px;
    padding: 12px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: transparent;
    color: var(--text-secondary);
    cursor: pointer;
    font: inherit;
}

.logout-button:hover {
    background: #263247;
    color: var(--text-primary);
}

/* ========================================
   FAVORITEN
======================================== */

/* Button oberhalb der Lernkarte */

.favorite-button {
    display: block;
    margin: 0 0 12px auto;
    padding: 10px 16px;

    background: var(--bg-card);
    color: var(--text-secondary);

    border: 1px solid var(--border);
    border-radius: 9px;

    font-size: 13px;
    font-weight: 600;

    cursor: pointer;
    transition: 0.2s;
}

.favorite-button:hover:not(:disabled) {
    background: var(--bg-card-hover);
    border-color: var(--accent);
    color: var(--text-primary);
}

.favorite-button.is-favorite {
    color: #fbbf24;
    border-color: #b7791f;
    background: rgba(251, 191, 36, 0.08);
}

.favorite-button:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

/* Stern in der Kartenübersicht */

.card-favorite-indicator {
    color: #fbbf24 !important;
    font-size: 18px;
    margin-top: 4px;
}

/* Favoriten-Navigation */

.sidebar nav a {
    cursor: pointer;
}

/* PERSÖNLICHE NOTIZEN */

.notes-section {
    margin-top: 28px;
    padding: 24px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 14px;
}

.notes-section h3 {
    margin: 0 0 6px;
    color: var(--text-primary);
}

.notes-section p {
    margin: 0 0 18px;
    color: var(--text-secondary);
    font-size: 14px;
}

.notes-section textarea {
    width: 100%;
    min-height: 120px;
    padding: 14px;
    resize: vertical;
    background: var(--bg-main);
    color: var(--text-primary);
    border: 1px solid var(--border);
    border-radius: 9px;
    font: inherit;
    box-sizing: border-box;
}

.notes-section textarea:focus {
    outline: none;
    border-color: var(--accent);
}

.notes-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 12px;
    margin-top: 12px;
    flex-wrap: wrap;
}

#save-note {
    padding: 10px 16px;
    background: var(--accent);
    color: white;
    border: none;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 600;
}

#save-note:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

#note-status {
    color: var(--text-secondary);
    font-size: 13px;
}