/* =========================================
         1. DEFINICE PROMĚNNÝCH A BAREV
         ========================================= */
      :root {
        color-scheme: light dark; 
        
        --bg: #f3f4f6;           
        --card-bg: #ffffff;      
        --card-active: #e5e7eb;  
        
        --text-main: #111827;    
        --text-sec: #6b7280;     
        
        --brand: #0891b2;        
        --active-indicator: #16a34a; 
        
        --input-bg: #ffffff;
        --border: #d1d5db;
        --shadow: 0 1px 3px rgba(0,0,0,0.1);
        
        --btn-text: #ffffff;
        --time-bg: rgba(0,0,0,0.04); 
      }

      [data-theme="dark"] {
        --bg: #121212;
        --card-bg: #1e1e1e;
        --card-active: #252525;
        
        --text-main: #f3f4f6;    
        --text-sec: #9ca3af;
        
        --brand: #0284c7;        
        --active-indicator: #4ade80; 
        
        --input-bg: #262626;
        --border: #333333;
        --shadow: 0 4px 6px rgba(0,0,0,0.3);
        
        --btn-text: #ffffff;
        --time-bg: rgba(255,255,255,0.05); 
      }
      
      * { box-sizing: border-box; }
      
      body { 
        background-color: var(--bg); 
        color: var(--text-main); 
        font-family: 'Inter', sans-serif;
        margin: 0; padding: 0; 
        padding-bottom: 90px; 
        user-select: none; 
        overscroll-behavior-y: contain; 
        -webkit-font-smoothing: antialiased; 
        transition: background-color 0.3s ease, color 0.3s ease;
      }
      
      .main-wrapper { padding: 15px; width: 100%; max-width: 600px; margin: 0 auto; }

      /* =========================================
         2. INDIKÁTOR STAŽENÍ
         ========================================= */
      #pull-indicator { 
        height: 0; overflow: hidden; display: flex; justify-content: center; 
        align-items: center; background: var(--bg); color: var(--text-sec); 
        font-size: 0.85rem; transition: height 0.1s ease-out; gap: 8px; font-weight: 500;
      }
      #pull-indicator svg { width: 16px; height: 16px; fill: var(--text-sec); transition: transform 0.3s; }
      #pull-indicator.ready svg { transform: rotate(180deg); fill: var(--active-indicator); }
      #pull-indicator.ready { color: var(--active-indicator); }
      
      /* =========================================
         3. HLAVIČKA A NAVIGACE
         ========================================= */
      /* Ve výchozím stavu skryto, ovládá JS */
      .header-container { text-align: center; margin-bottom: 24px; position: relative; padding-top: 10px; display: none;}
      
      h1 { 
        font-weight: 800; letter-spacing: 0.5px; color: var(--text-main); 
        margin: 0; text-transform: none; font-size: 1.4rem; margin-top: 5px;
      }
      
      .product-tagline {
        font-size: 0.75rem; color: var(--text-sec); letter-spacing: 0.04em;
        margin-top: 4px; font-weight: 400; opacity: 0.8;
      }
      
      .instructor-name { color: var(--brand); font-size: 0.95rem; margin-top: 8px; margin-bottom: 12px; font-weight: 500;}

      .top-btn { 
        background: var(--input-bg); color: var(--text-main); border: 1px solid var(--border); 
        font-size: 0.85rem; padding: 6px 12px; border-radius: 8px; position: absolute; 
        top: 10px; cursor: pointer; display: flex; align-items: center; justify-content: center;
        transition: background 0.2s; height: 32px;
      }
      .top-btn:active { background: var(--card-active); }
      .theme-btn { left: 0; border: none; background: transparent; font-size: 1.2rem; padding: 0;}
      .today-btn { right: 0; font-size: 0.7rem; font-weight: 600; letter-spacing: 0.5px; }

      /* Hlavní kontejner rozvrhu - ve výchozím stavu skrytý */
      #view-schedule { display: none; }

      .nav-bar { 
        display: flex; justify-content: center; align-items: center; 
        gap: 12px; margin-top: 20px; margin-bottom: 20px; 
      }
      
      .nav-btn { 
        background: transparent; border: 1px solid var(--border); color: var(--brand); 
        font-size: 1rem; padding: 10px 16px; border-radius: 8px; cursor: pointer; transition: background 0.2s;
      }
      .nav-btn:active { background: var(--card-active); }
      
      .date-display { 
        font-size: 1rem; font-weight: 600; color: var(--text-main); background: var(--input-bg); 
        padding: 10px 24px; border-radius: 8px; border: 1px solid var(--border); 
        min-width: 140px; position: relative; 
      }
      #date-picker { position: absolute; top: 0; left: 0; width: 100%; height: 100%; opacity: 0; cursor: pointer; }
      
      #stats-display { text-align: center; width: 100%; }
      .stats-badge { 
        display: inline-flex; align-items: center; background: var(--input-bg); 
        color: var(--text-sec); padding: 6px 14px; border-radius: 6px; 
        font-size: 0.85rem; font-weight: 500; margin-top: 15px; border: 1px solid var(--border); 
      }
      
      .loading { text-align: center; color: var(--text-sec); margin-top: 60px; font-size: 0.9rem; font-weight: 400;}
      
      /* =========================================
         4. PŘIHLAŠOVACÍ FORMULÁŘ
         ========================================= */
      #login-form { display: none; text-align: center; margin-top: 60px; padding: 15px;}
      .login-title { font-size: 1.4rem; font-weight: 700; margin-bottom: 8px; color: var(--text-main); }
      .login-description { font-size: 0.9rem; color: var(--text-sec); margin-bottom: 30px; line-height: 1.5; }
      
      input[type="tel"] { 
        width: 100%; padding: 16px; margin-bottom: 24px; background: var(--input-bg); 
        border: 1px solid var(--border); border-radius: 8px; color: var(--text-main); 
        font-size: 1.5rem; font-family: 'Inter', sans-serif; font-weight: 500;
        text-align: center; letter-spacing: 1px; outline: none; transition: border-color 0.2s;
      }
      input[type="tel"]:focus { border-color: var(--brand); }

      .btn { 
        padding: 16px 32px; background: var(--brand); color: var(--btn-text); border: none; 
        border-radius: 8px; font-weight: 600; font-size: 1rem; cursor: pointer; width: 100%; 
        max-width: 320px; font-family: 'Inter', sans-serif; box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15); 
      }
      
      /* =========================================
         5. KARTY LEKCÍ (ROZVRH)
         ========================================= */
      .card { 
        width: 100%; background-color: var(--card-bg); border-left: 4px solid var(--brand); 
        border-radius: 8px; padding: 0; margin-bottom: 12px; display: flex; 
        justify-content: flex-start; align-items: stretch; transition: transform 0.2s ease; 
        overflow: hidden; box-shadow: var(--shadow);
      }
      .card.snb { border-left-color: #FFEB3B; }
      .card.active-now { border-left-color: var(--active-indicator) !important; border-left-width: 6px; background-color: var(--card-active);}
      
      /* NOVÝ STYL PRO MINULÉ LEKCE */
      .card.past {
        opacity: 0.5; /* Průhlednost */
        filter: grayscale(100%); /* Odbarvení (šedá) */
        box-shadow: none; /* Zrušení stínu */
        background-color: var(--bg); /* Splynutí s pozadím */
      }

      .time-box { 
        width: 75px; min-width: 75px; text-align: center; border-right: 1px solid var(--border); 
        display: flex; flex-direction: column; justify-content: center; align-items: center;
        padding: 12px 0; background: var(--time-bg); gap: 4px;
      }
      .time-start { font-size: 1.25rem; font-weight: 700; color: var(--text-main); line-height: 1; }
      .time-end { font-size: 0.85rem; font-weight: 500; color: var(--text-sec); line-height: 1; }
      
      .info-box { flex: 1; min-width: 0; padding: 12px 16px; display: flex; flex-direction: column; justify-content: center; gap: 4px; }
      .client-name { font-size: 1.05rem; font-weight: 500; color: var(--text-main); white-space: pre-wrap; word-wrap: break-word; line-height: 1.4; }
      .lesson-type { font-size: 0.72rem; color: var(--text-sec); text-transform: uppercase; letter-spacing: 0.08em; font-weight: 600; opacity: 0.8; }
      
      .error-box { background-color: #3e1818; border: 1px solid #ff4444; color: #ffcccc; padding: 15px; border-radius: 8px; text-align: center; margin-top: 20px; font-size: 0.9rem;}
      
      .logout-link { display: block; text-align: center; margin-top: 40px; color: var(--text-sec); font-size: 0.85rem; text-decoration: none; padding: 10px; cursor: pointer; transition: color 0.2s;}
      .logout-link:hover { color: var(--brand); }
      
      .sos-panel { margin-top: 30px; padding-top: 20px; border-top: 1px solid var(--border); text-align: center; }
      .sos-label { font-size: 0.75rem; text-transform: uppercase; letter-spacing: 1px; color: var(--text-sec); margin-bottom: 12px; font-weight: 600; }
      .sos-btn { display: inline-block; background: transparent; color: #ef4444; border: 1px solid #ef4444; padding: 8px 16px; border-radius: 6px; font-size: 0.85rem; margin: 0 4px; text-decoration: none; font-weight: 500; transition: background 0.2s; }
      .sos-btn:active { background: rgba(239, 68, 68, 0.1); }
      
      .empty-state { text-align: center; color: var(--text-sec); margin-top: 50px; padding: 20px; border: 1px dashed var(--border); border-radius: 8px; font-size: 0.95rem; }

      /* =========================================
         6. STYLY PRO KALENDÁŘ A SPODNÍ LIŠTU
         ========================================= */
      
      .bottom-nav { 
        position: fixed; bottom: 0; left: 0; width: 100%; 
        background: var(--card-bg); border-top: 1px solid var(--border); 
        display: flex; justify-content: space-around; 
        padding: 10px 0; padding-bottom: max(10px, env(safe-area-inset-bottom)); 
        z-index: 100; box-shadow: 0 -2px 10px rgba(0,0,0,0.05);
      }
      .nav-item { 
        display: flex; flex-direction: column; align-items: center; 
        color: var(--text-sec); text-decoration: none; font-size: 0.7rem; 
        cursor: pointer; flex: 1; transition: color 0.2s;
        text-transform: uppercase; letter-spacing: 0.5px; font-weight: 500;
      }
      .nav-item.active { color: var(--brand); font-weight: 700; }
      .nav-item svg { width: 24px; height: 24px; margin-bottom: 5px; fill: currentColor; }

      #view-calendar { display: none; padding-top: 20px;}
      .cal-title { text-align: center; font-size: 1.1rem; font-weight: 700; margin-bottom: 20px; color: var(--text-main); }
      
      .cal-grid { display: grid; grid-template-columns: repeat(7, 1fr); gap: 8px; text-align: center; width: 100%; }
      .cal-day-name { font-size: 0.75rem; color: var(--text-sec); font-weight: 600; padding-bottom: 5px; opacity: 0.7;}
      
      .cal-cell { 
        aspect-ratio: 1; background: var(--card-bg); border-radius: 10px; 
        display: flex; flex-direction: column; align-items: center; justify-content: center; 
        position: relative; border: 1px solid var(--border); 
        font-size: 1rem; font-weight: 500; box-shadow: var(--shadow); color: var(--text-main);
      }
      .cal-cell.empty { background: transparent; border: none; box-shadow: none; }
      
      .cal-strip { 
        position: absolute; bottom: 0; left: 0; width: 100%; height: 5px; 
        border-radius: 0 0 10px 10px; display: none;
      }
      .is-working .cal-strip { display: block; background-color: var(--active-indicator); }
      .is-working { font-weight: 700; }
      
      .cal-today { border: 2px solid var(--brand); color: var(--brand); font-weight: 700; }

      .cal-past { 
        opacity: 0.4; 
        background-color: var(--bg);
      }
      .cal-past .cal-strip { background-color: var(--text-sec); }