:root {
    --primary: #6366f1;
    --bg-color: #f8fafc;
    --card-bg: #ffffff;
    --text-color: #1e293b;
    --border-color: #e2e8f0;
}

.dark-mode {
    --bg-color: #0f172a;
    --card-bg: #1e293b;
    --text-color: #f1f5f9;
    --border-color: #334155;
}

body { font-family: 'Inter', sans-serif; background-color: var(--bg-color); color: var(--text-color); display: flex; justify-content: center; padding: 20px; margin: 0; }
.container { width: 100%; max-width: 500px; background: var(--card-bg); padding: 40px; border-radius: 24px; box-shadow: 0 10px 30px rgba(0,0,0,0.06); }
.header-actions { text-align: right; margin-bottom: 10px; }
.toggle-btn { background: #f1f5f9; color: #1e293b; font-size: 12px; padding: 6px 12px; border-radius: 8px; border: 1px solid var(--border-color); }
h1 { font-weight: 800; font-size: 32px; text-align: center; margin-bottom: 20px; letter-spacing: -1px; }

.input-group { display: flex; flex-direction: column; gap: 8px; margin-bottom: 25px; }
label { font-weight: 700; font-size: 14px; margin-top: 10px; }
input, select { padding: 14px; border: 2px solid var(--border-color); border-radius: 12px; font-family: 'Inter', sans-serif; font-weight: 600; background: var(--card-bg); color: var(--text-color); }

button { font-family: 'Inter', sans-serif; font-weight: 700; cursor: pointer; border: none; border-radius: 12px; transition: 0.2s; }
.primary-btn { background: var(--primary); color: white; padding: 16px; margin-top: 10px; width: 100%; }
.clear-btn { background: #cbd5e1; color: #475569; padding: 14px; margin-top: 8px; width: 100%; }

.stats-dashboard { display: grid; grid-template-columns: repeat(3, 1fr); gap: 10px; margin: 30px 0; }
.stat-card { background: var(--bg-color); padding: 15px 5px; border-radius: 16px; text-align: center; border: 1px solid var(--border-color); }
.stat-value { display: block; font-size: 24px; font-weight: 800; color: var(--primary); }
.stat-label { font-size: 9px; font-weight: 800; opacity: 0.6; }

.progress-container { width: 100%; height: 14px; background: #e2e8f0; border-radius: 10px; margin-top: 20px; overflow: hidden; }
.progress-bar-fill { height: 100%; background: var(--primary); width: 0%; transition: 0.5s; }
.progress-text { text-align: center; font-weight: 800; color: var(--primary); margin-top: 8px; }
.task-count-sub { text-align: center; font-size: 11px; font-weight: 700; opacity: 0.5; margin-top: 4px; }

#taskList { list-style: none; padding: 0; margin-top: 30px; }
.task-item { background: var(--card-bg); border: 2px solid var(--border-color); border-radius: 20px; padding: 20px; margin-bottom: 12px; display: flex; flex-direction: column; gap: 15px; }
.task-main { display: flex; align-items: flex-start; gap: 15px; }
.task-info { display: flex; flex-direction: column; gap: 4px; }
.task-info strong { font-weight: 800; font-size: 18px; }
.task-info small { font-weight: 600; color: #64748b; font-size: 13px; }
.overdue-tag { color: #ef4444; font-weight: 800; font-size: 12px; }
.difficulty-tag { color: #10b981; font-weight: 800; font-size: 12px; }

.task-actions { display: flex; gap: 8px; }
.task-actions button { flex: 1; padding: 12px; font-size: 13px; }
.timer-btn { background: var(--primary); color: white; }
.edit-btn { background: #f59e0b; color: white; }
.del-btn { background: #ef4444; color: white; }

.timer-card { background: var(--bg-color); padding: 30px; border-radius: 24px; border: 3px solid var(--primary); margin: 25px 0; text-align: center; }
.timer-picker { display: flex; align-items: center; justify-content: center; gap: 15px; margin: 20px 0; }
.picker-group { display: flex; flex-direction: column; align-items: center; width: 100px; }
.big-number { font-size: 54px; font-weight: 800; color: var(--primary); line-height: 1.1; margin: 5px 0; width: 80px; text-align: center; }
.picker-separator { font-size: 40px; font-weight: 800; color: var(--primary); margin-top: -20px; }

.arrow-btn { background: #f1f5f9; color: var(--primary); width: 60px; height: 30px; border-radius: 8px; font-size: 14px; }
.dual-arrows { display: flex; gap: 5px; }
.small-arrow { background: #f1f5f9; color: var(--primary); width: 35px; height: 30px; border-radius: 8px; font-size: 12px; }

.arrow-btn:hover, .small-arrow:hover { background: var(--border-color); }
.picker-label { font-size: 10px; font-weight: 800; opacity: 0.5; letter-spacing: 1px; margin-top: 5px; }

#timerDisplay { font-size: 64px; font-weight: 800; color: var(--primary); text-shadow: 0 4px 10px rgba(99, 102, 241, 0.2); margin: 15px 0; }
.timer-actions { display: flex; gap: 10px; justify-content: center; }
.pause-btn { background: #f59e0b; color: white; padding: 12px 30px; }
.stop-btn { background: #ef4444; color: white; padding: 12px 30px; }