:root {
  /* Color Palette - Modern & Soft */
  --bg-gradient: linear-gradient(135deg, #1d3161 0%, #151e3c 100%);
  --sidebar-bg: rgba(255, 255, 255, 0.04);
  --main-card-bg: rgba(255, 255, 255, 0.08);
  --text-primary: #ffffff;
  --text-secondary: rgba(255, 255, 255, 0.6);
  
  --color-focus: #5de59d; /* Fresh Green */
  --color-short-break: #4ac7f2; /* Calm Blue */
  --color-long-break: #d37cf2; /* Soft Purple */
  
  --button-hover-bg: rgba(255, 255, 255, 0.15);
  --radius-xl: 24px;
  --radius-l: 16px;
  --radius-m: 10px;
}

body {
  margin: 0;
  padding: 0;
  height: 100vh;
  background: var(--bg-gradient);
  color: var(--text-primary);
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Helvetica, Arial, sans-serif;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow: hidden; /* Modern look, no scroll */
}

/* Main Layout Container */
.dashboard-container {
  display: flex;
  width: 90vw;
  height: 85vh;
  max-width: 1400px;
  background: var(--sidebar-bg);
  backdrop-filter: blur(20px);
  border-radius: var(--radius-xl);
  border: 1px solid rgba(255, 255, 255, 0.05);
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.2);
}

/* ================== LEFT SIDEBAR (Controls) ================== */
.sidebar {
  width: 250px;
  padding: 40px;
  border-right: 1px solid rgba(255, 255, 255, 0.05);
  display: flex;
  flex-direction: column;
  gap: 40px;
}

.title-section h1 { font-size: 24px; font-weight: 700; margin: 0; }
.title-section h1 span { color: var(--color-focus); }
.title-section p { color: var(--text-secondary); margin: 5px 0 0; font-size: 14px; }

/* Group titles like "TIMER MODES" */
.sidebar h2 { font-size: 12px; font-weight: 600; color: var(--text-secondary); text-transform: uppercase; letter-spacing: 1px; margin: 0; }

.control-group { display: flex; flex-direction: column; gap: 15px; }

/* Control Buttons (Vertical List) */
.control-btn {
  background: transparent;
  border: 1px solid rgba(255, 255, 255, 0.1);
  color: var(--text-primary);
  padding: 12px 20px;
  border-radius: var(--radius-m);
  cursor: pointer;
  font-weight: 500;
  display: flex;
  justify-content: space-between; /* Arrow on right */
  align-items: center;
  transition: all 0.2s ease;
}

.control-btn:hover { background: var(--button-hover-bg); border-color: rgba(255, 255, 255, 0.2); }
.control-btn .label { display: flex; align-items: center; gap: 10px; }

/* Highlight active mode */
.control-btn.active { background: rgba(93, 229, 157, 0.1); border-color: var(--color-focus); color: var(--color-focus); font-weight: 600; }
.control-btn.active[onclick*="5, 'Short Break'"] { background: rgba(74, 199, 242, 0.1); border-color: var(--color-short-break); color: var(--color-short-break); }
.control-btn.active[onclick*="15, 'Long Break'"] { background: rgba(211, 124, 242, 0.1); border-color: var(--color-long-break); color: var(--color-long-break); }

/* Play/Pause Button on Sidebar */
#start-btn {
  background: var(--color-focus);
  color: #12182d; /* Dark text on green */
  font-weight: 700;
  border: none;
  justify-content: center;
  gap: 10px;
}
#start-btn:hover { background: #4bd28c; }

/* ================== MAIN CONTENT (Focus Area) ================== */
.main-content {
  flex: 1;
  padding: 60px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: space-between; /* Space out top label, middle timer, bottom info */
}

.mode-indicator { color: var(--color-focus); font-weight: 500; }

/* The large main timer card */
.timer-container {
  background: var(--main-card-bg);
  padding: 30px 60px;
  border-radius: var(--radius-l);
  border: 1px solid rgba(255, 255, 255, 0.05);
  box-shadow: 0 5px 25px rgba(0, 0, 0, 0.15);
  display: flex;
  align-items: baseline; /* Align bottom of numbers */
  gap: 5px;
}

#timer-minutes { font-size: 140px; font-weight: 800; line-height: 1; margin: 0; }
#timer-seconds { font-size: 80px; font-weight: 500; color: var(--text-secondary); margin: 0; position: relative; top: -10px; }

/* Extra info below timer */
.session-stats { display: flex; gap: 40px; color: var(--text-secondary); }
.session-stats span { font-weight: 600; color: var(--text-primary); }