/* --- SISTEMA DE TEMAS --- */
:root {
    --primary: #2563eb;
    --bg: #f3f4f6;
    --sidebar: #ffffff;
    --text-main: #1f2937;
    --text-muted: #6b7280;
    --card-bg: #ffffff;
    --border-color: #e5e7eb;
    --danger: #ef4444; 
    --danger-bg: #fef2f2;
    --success: #10b981;
}

[data-theme="dark"] {
    --primary: #3b82f6; --bg: #111827; --sidebar: #1f2937;
    --text-main: #f9fafb; --text-muted: #9ca3af; --card-bg: #1f2937;
    --border-color: #374151; --danger: #f87171; --danger-bg: #450a0a;
}

[data-theme="pink"] {
    --primary: #db2777; --bg: #fdf2f8; --sidebar: #fce7f3;
    --text-main: #831843; --text-muted: #9d174d; --card-bg: #ffffff;
    --border-color: #fbcfe8; --danger: #e11d48; --danger-bg: #fff1f2;
}

[data-theme="space"] {
    --primary: #8b5cf6; --bg: #020617; --sidebar: #0f172a;
    --text-main: #e2e8f0; --text-muted: #94a3b8; --card-bg: #1e293b;
    --border-color: #334155; --danger: #f43f5e; --danger-bg: #4c0519;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

body { font-family: 'Inter', system-ui, sans-serif; background-color: var(--bg); color: var(--text-main); margin: 0; display: flex; height: 100vh; overflow: hidden; transition: 0.3s; }

/* HEADER & SEARCH */
.mobile-header { display: flex; background: var(--sidebar); padding: 12px 15px; border-bottom: 1px solid var(--border-color); align-items: center; justify-content: space-between; position: fixed; top: 0; left: 0; right: 0; z-index: 50; gap: 10px; transition: 0.3s; }
.menu-btn { background: none; border: none; font-size: 1.5rem; color: var(--text-main); cursor: pointer; padding: 5px; }
.search-bar { flex: 1; display: flex; align-items: center; background: var(--bg); border-radius: 20px; padding: 5px 15px; }
.search-bar input { border: none; background: transparent; padding: 10px 8px; width: 100%; margin: 0; outline: none; font-size: 1rem; color: var(--text-main); }

/* SIDEBAR */
nav { width: 280px; background: var(--sidebar); border-right: 1px solid var(--border-color); display: flex; flex-direction: column; padding: 20px; height: 100vh; overflow-y: auto; transition: 0.3s ease; z-index: 100; }
.nav-logo { font-weight: 800; font-size: 1.2rem; margin-bottom: 30px; display: flex; justify-content: space-between; }
.close-sidebar { display: none; background: none; border: none; font-size: 1.5rem; cursor: pointer; padding: 10px; color: var(--text-main); }
.nav-item { padding: 16px 12px; border-radius: 8px; cursor: pointer; margin-bottom: 5px; display: flex; align-items: center; gap: 10px; color: var(--text-muted); font-weight: 500; font-size: 1.1rem; }
.nav-item:hover, .nav-item.active { background: var(--bg); color: var(--text-main); }
.color-dot { width: 14px; height: 14px; border-radius: 50%; }

/* MAIN CONTENT */
main { flex: 1; overflow-y: auto; padding: 80px 20px 100px 20px; }
.view { display: none; } .view.active { display: block; }

/* FAB */
.fab { position: fixed; bottom: 25px; right: 25px; width: 65px; height: 65px; border-radius: 50%; background: var(--primary); color: white; display: flex; align-items: center; justify-content: center; font-size: 2rem; box-shadow: 0 4px 10px rgba(0,0,0,0.3); border: none; cursor: pointer; z-index: 90; transition: transform 0.2s; }
.fab:active { transform: scale(0.95); }

/* FORMULARIO */
.form-header { display: flex; justify-content: space-between; align-items: center; margin-bottom: 25px; }
.form-close-btn { font-size: 1.2rem; background: none; border: none; font-weight: bold; padding: 10px; cursor: pointer; color: var(--text-main); }
.big-control { width: 100%; padding: 16px; margin-bottom: 20px; border: 2px solid var(--border-color); border-radius: 12px; font-family: inherit; font-size: 1.1rem; background: var(--card-bg); color: var(--text-main); }
.big-control:focus { border-color: var(--primary); outline: none; }
.btn-massive { background: var(--primary); color: white; border: none; padding: 18px 20px; border-radius: 12px; cursor: pointer; font-weight: bold; font-size: 1.2rem; width: 100%; margin-top: 10px; }

/* CARDS */
.grid-cards { display: grid; grid-template-columns: repeat(auto-fill, minmax(280px, 1fr)); gap: 15px; }
.card { background: var(--card-bg); padding: 18px; border-radius: 12px; box-shadow: 0 2px 4px rgba(0,0,0,0.1); border-left: 6px solid var(--text-muted); transition: 0.2s opacity; border: 1px solid var(--border-color); }
.card.urgent { border-left-color: var(--danger) !important; border: 2px solid var(--danger); background: var(--danger-bg); }
.card.urgent .badge-date { background: var(--danger); color: white; }
.card.completed { opacity: 0.6; border-left-color: var(--success) !important; }
.card.completed h4 { text-decoration: line-through; color: var(--text-muted); }

.badges-container { display: flex; justify-content: space-between; align-items: start; margin-bottom: 10px; }
.badge-date { font-size: 0.8rem; font-weight: bold; padding: 6px 10px; border-radius: 6px; background: var(--bg); color: var(--text-main); border: 1px solid var(--border-color); }
.badge-diff { font-size: 0.8rem; padding: 5px 8px; border-radius: 6px; border: 1px solid var(--border-color); color: var(--text-main); }
.big-checkbox { width: 28px; height: 28px; cursor: pointer; accent-color: var(--success); }
.btn-toggle-details { width: 100%; background: var(--bg); border: 1px solid var(--border-color); padding: 12px; border-radius: 8px; font-weight: bold; color: var(--text-main); margin-top: 10px; cursor: pointer; font-size: 0.9rem; }
.card-details { display: none; margin-top: 15px; border-top: 1px solid var(--border-color); padding-top: 15px; }

.subtask-item { display: flex; align-items: center; gap: 12px; font-size: 1rem; margin-bottom: 10px; padding: 5px 0; color: var(--text-main); }
.subtask-item input[type="checkbox"] { width: 22px; height: 22px; cursor: pointer; }
.subtask-item.done span { text-decoration: line-through; color: var(--text-muted); }
.btn-del-sub { background: none; border: none; color: var(--danger); font-size: 1.2rem; cursor: pointer; padding: 5px 10px; margin-left: auto; }

.add-subtask-wrapper { display: flex; gap: 8px; margin-top: 15px; }
.add-subtask-wrapper input { padding: 12px; border: 1px solid var(--border-color); border-radius: 8px; font-size: 1rem; flex: 1; background: var(--bg); color: var(--text-main); }
.add-subtask-wrapper button { padding: 0 18px; background: var(--border-color); color: var(--text-main); border: none; border-radius: 8px; cursor: pointer; font-weight: bold; font-size: 1.2rem; }

/* FILTROS Y PROMEDIO */
.filter-tabs { display: flex; gap: 10px; margin-bottom: 20px; background: var(--border-color); padding: 6px; border-radius: 10px; width: fit-content; }
.filter-btn { padding: 10px 20px; border: none; background: transparent; border-radius: 8px; cursor: pointer; font-weight: bold; color: var(--text-main); font-size: 1rem; }
.filter-btn.active { background: var(--card-bg); color: var(--text-main); box-shadow: 0 2px 4px rgba(0,0,0,0.1); }
.subject-header { display: flex; justify-content: space-between; align-items: center; flex-wrap: wrap; gap: 15px; margin-bottom: 20px; }
.average-badge { background: linear-gradient(135deg, #fbbf24 0%, #f59e0b 100%); color: white; padding: 10px 20px; border-radius: 12px; font-weight: bold; font-size: 1.2rem; box-shadow: 0 4px 6px rgba(0,0,0,0.2); display: flex; align-items: center; gap: 8px; }
.average-badge span { font-size: 1.4rem; background: rgba(255,255,255,0.2); padding: 2px 8px; border-radius: 6px; }
.grade-badge { background: #fef3c7; color: #d97706; border: 1px solid #fde68a; padding: 4px 10px; border-radius: 6px; font-size: 0.85rem; font-weight: bold; display: flex; align-items: center; gap: 5px; }

/* DEV CARD */
.dev-card { position: fixed; bottom: 100px; left: 20px; right: 20px; max-width: 300px; background: var(--card-bg); padding: 15px; border-radius: 16px; box-shadow: 0 10px 40px rgba(0,0,0,0.3); z-index: 1000; display: flex; align-items: center; gap: 12px; border: 1px solid var(--border-color); animation: slideUp 0.6s cubic-bezier(0.175, 0.885, 0.32, 1.275); }
.dev-avatar { width: 40px; height: 40px; background: var(--primary); color: white; border-radius: 10px; display: flex; align-items: center; justify-content: center; }
.dev-info h4 { margin: 0; font-size: 0.9rem; color: var(--text-main); }
.dev-info p { margin: 0; font-size: 0.75rem; color: var(--text-muted); }
.close-dev-card { margin-left: auto; background: none; border: none; cursor: pointer; color: var(--text-muted); }
@keyframes slideUp { from { transform: translateY(200%); opacity: 0; } to { transform: translateY(0); opacity: 1; } }

@media (max-width: 768px) {
    nav { position: fixed; left: 0; top: 0; transform: translateX(-100%); width: 85%; max-width: 320px; }
    nav.open { transform: translateX(0); box-shadow: 4px 0 20px rgba(0,0,0,0.5); }
    .close-sidebar { display: block; }
}